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Full text of "The freshwater fishes of British Guiana, including a study of the ecological grouping of species and the relation of the fauna of the plateau to that of the lowlands"



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Memoirs Carnegie Museum, Vol. v. 



Frontispiece. 




The Kaietevk Falls. Height 741 feet. 



MEMOIRS 



OF THE 



CAKNEGIE MUSEUM 



Vol. v. 

(Publications of the Carnegie Museum: Serial No. 67). 



W. J. HOLLAND, Editor. 



PITTSBURGH 

Published by the Autiioeity of the Board of Trustees of the 

CARNEGIE INSTITUTE 

JUNE, 1912. 



Press of 

the nev. era printing comp*nf 

Lancaster. Pa. 



°) 









\ 



OU-O^lr 



THE FRESHWATER FISHES OF BRITISH GUIANA, INCLUDING 

A STUDY OF THE ECOLOGICAL GROUPING OF SPECIES 

AND THE RELATION OF THE FAUNA OF THE 

PLATEAU TO THAT OF THE LOWLANDS. 



By C. H. EIGENMANN, Ph.D. 

Dean of the Graduate School of the Indiana State University, and Curator of 
Ichthyology in the Carnegie Museum. 



in 



" 



PREFATORY NOTE 



The following pages, constituting the Fifth Volume of the Memoirs of the 
Carnegie Museum, embody the results of the investigations made by Dr. C. H. 
Eigenmann upon the piscine fauna of the rivers of British Guiana. 

Having been granted temporary leave of absence from the Indiana State Uni- 
versity, where he is the Dean of the Graduate School, Dr. Eigenmann went to 
British Guiana in the fall of 1908, having the assurance of the financial support of 
the Carnegie Museum, both in meeting the expenses of his expedition and in pub- 
lishing the results thereof. The typical portions of the collections made by him 
are preserved in the Carnegie Museum, including all unica. A second set, includ- 
ing, so far as possible, cotypes of the new species, was reserved for the Indiana 
State University. It has been arranged to dispose of the remainder of the collec- 
tion by exchange with the leading museums of America and Europe. 

The Editor, in presenting this work to the scientific public, is animated by 
the hope that it may prove of value to the students of biology in all parts of the 
world, and tend to shed at least a little light upon some of the countless problems 
which confront the student of vital phenomena. 

W. J. Holland. 

Pittsburgh, Dec. 1, 1911. 



LETTER OF TRANSMITTAL 



Dr. W. J. Holland, 

Director Carnegie Museum, Pittsburgh, Pa. 
My dear sir: 

By accident you and I came to occupy contiguous seats in an excursion from 
Colorado Springs to Cripple Creek, after the close of the Denver meeting of the 
American Association for the Advancement of Science in 1901. 

I am transmitting one of the indirect results of that pleasant ride. Since that 
chance meeting we have frequently discussed South America, a continent in which 
a growing series of converging interests meet, the continent which served as the 
training ground of Spix, Martius, Castelnau, Miiller, Darwin, Bates, Wallace, 
Agassiz, and Hatcher, a land in which there is a great wealth of many sorts of 
animals and plants, and in which fresh-water fishes have evolved in the greatest 
profusion, a continent which will in the centuries to come furnish homes to count- 
less millions of men. 

I have been interested in South American fresh-water fishes for twenty-five 
years. A little over two years ago it became necessary in continuance of my work 
to visit British Guiana. The Trustees of Indiana University gave me leave of 
absence. I applied to various other institutions for assistance, but met everywhere 
with refusals. When I visited you in August, 1908, on my way to Guiana, you 
pledged the Carnegie Museum to help. Both the authorities of Indiana University 
and you have done everything possible to bring my report to a successful conclusion. 
It is a great satisfaction to me that the assistance furnished by the Carnegie Museum 
has brought it such rich returns in valuable specimens. Since my return from 
Guiana in December, 1908, all of the material collected has been examined, and 
the results of the examination together with an account of the Guiana Expedition 
are herewith transmitted for publication. This paper was prepared in the Zoolog- 
ical Laboratory of Indiana University and forms "Contribution No. 114" of that 

laboratory. 

Cordially yours, 

C. H. ElGENMANN. 
December 1, 1910. 



TABLE OF CONTENTS. 



Prefatory Note ............ v 

Letter of Transmittal vii 

Table of Contents ............ ix 

List of Figures in Text xi 

List of Plates xiii 

Errata and Corrigenda xix 

Memoir: The Freshwater Fishes of British Guiana. 

Introduction 1^4 

Chapter I. British Guiana 5-14 

Chapter II. Earlier Works on the Fishes of British Guiana . . . 15-29 

Chapter III. General Account of the Expedition 30-59 

Chapter IV. Geographical Distribution of the Freshwater Fishes of 

British Guiana ......... 60-86 

Chapter V. Ecological Combinations of Species 87-93 

Chapter VI. The Ichthyic Fauna of the Pbtaro River and of the Guiana 

Plateau 94-105 

Chapter VII. General Considerations 106-115 

Chapter VIII. Systematic Account of the Freshwater Fishes of British 

Guiana 116-529 

Chapter IX. Bibliography 530-554 

Index 555-578 



LIST OF FIGURES IN TEXT. 



Page. 

Mouth of the Demerara River at Georgetown, British Guiana 30 

A trench in Georgetown 31 

View of the lowlands looking seaward from the railway near Mahaica 32 

View of the drainage canal at Cane-Grove Corner 33 

Photograph of Carnegiella strigala in aquarium 35 

View on the right bank of the Demerara River 36 

View of creek filled with brush-wood above Wismar at low tide. Indians are poisoning 

the creek 37 

Fish-fence made of reeds and banana-leaves on creek above Wismar. Indian with bow 

and arrow ready to shoot larger fishes brought up by poison 38 

View on bayou back of Christianburg. Indian fishing from his corial 39 

Indian women pounding leaves in a hollow on the ground preparatory to using the 

pulp for poisoning a stream on Gluck Island 40 

Small stream on Gluck Island dammed by Indian women before putting in the poison- 
ous leaf-pulp 41 

Edge of bayou between right bank of Essequibo and outlying sand-bar at Rockstone . 42 
Looking across the Rapids of the Potaro River, at Tumatumari. Papaya-trees in 

foreground 44 

Albert, one of the Indian bearers, transporting goods at Kangaruma 46 

View looking up the Potaro River in the early morning. Glimpse of the Guiana 

Plateau in the distance 47 

Seining on a sand-bar below the Amatuk Cataract 48 

View on the Potaro River looking up stream at the point where the first glimpse of 

the Kaieteur Falls is caught 49 

Exposed left side of the bed of the Potaro River at Tukeit in the dry season 50 

Looking up the Potaro Valley from the brink of the Kaieteur Falls 51 

Looking down the Canyon of the Potaro River from the brink of the Kaieteur Falls . 52 
View looking up the dry bed of Shrimp Creek. Figure of man in middle distance 

shows height of rocky steps 53 

Diagrammatic representation of the contour of the Kaieteur Falls. (After Brown.) . . 56 

Table showing distribution of the fishes taken by C. H. Eigenmann in the Potaro 

River above the Kaieteur Falls 101 

xi 



Xll LIST OF FIGURES IN TEXT 

Bunocephalus amaurus Eigenmann. Type 127 

Agmus lyriformis Eigenmann. Type 128 

Teeth of Selenaspis herzbergi (Bloch) 141 

Teeth of Selenaspis passany (Cuvier and Valenciennes) 142 

Outlines of occipital processes of various individuals of Notarius grandicassis (Cuvier 

and Valenciennes) 143 

Outlines of occipital processes of various individuals of Notarius par?nocassis (Cuvier 

and Valenciennes) 144 

Outlines of occipital processes of three specimens of Notarius stricticassis (Cuvier and 

Valenciennes) 145 

Outline of premaxillary band of teeth in Megalonema platycephahim Eigenmann 150 

Outline of Pseudopimelodus villosus Eigenmann. Type 152 

Chasmocranus longior Eigenmann. Type 161 

Plecostomus hemiurus Eigenmann. Type 225 

Pseudancistrus nigrescens Eigenmann. Type 234 

Ancistrus lithurgicus Eigenmann. Type 241 

Tetragonopterus argenteus Cuvier 318 

Tetragonopterus chalceus Agassiz 319 

Maxillary bone of Rhinosardinia serrata Eigenmann 445 



LIST OF PLATES. 



Frontispiece: The Kaieteur Falls (Facing p. 1) 

Plate. 

I. Aspredo sicuephorus Cuvier and Valenciennes; Bunocephalus gronovii 

Bleeker. 
II. Bunocephalus chamaizelus Eigenmann; Bunocephalus amaurus Eigenmann. 
(Type.) 

III. Agmus lyriformis Eigenmann. (Type.) 

IV. Agmus scabriceps Eigenmann and Eigenmann. (Type.) 

V. Sciadeichthys flavescens (Cuvier and Valenciennes); Sciadeichthys proops 

(Cuvier and Valenciennes); Sciadeichthys parkeri (Traill). 
VI. Sciadeichthys proops (Cuvier and Valenciennes) ; Dorsal view (the so-called 

"monk"); Palatal view (the so-called "crucifix"); Lateral view. 
VII. Selenaspis herzbergi (Bloch); Selenaspis passany (Cuvier and Valenciennes). 
VIII. Notarius grandicassis (Cuvier and Valenciennes); Notarius parmocassis 
(Cuvier and Valenciennes); Notarius stricticassis (Cuvier and Valen- 
ciennes.) 
IX. Sciadeichthys emphysetus (Miiller and Troschel); Arius spixi (Agassiz); 
Hexanematichthys rugispinis (Cuvier and Valenciennes). 
X. Pseudopimelodus villosus Eigenmann. (Type); Megalonema platycephalum 

Eigenmann. (Type.) 
XL Pseudopimelodus albomarginatus Eigenmann. (Type); Brachijglanis melas 

Eigenmann. (Type.) 
XII. Brachyglanis phalacra Eigenmann. (Type); Microglaiiis poecilus Eigen- 
mann. (Type.) 

XIII. Brachijglanis phalacra Eigenmann. (Type) ; Leptoglanis essequibensis Eigen- 

mann. (Type.) 

XIV. Myoglanis potaroensis Eigenmann. (Type); Chasmocranus longior Eigen- 

mann. (Type.) 
XV. Chasmocranus brevior Eigenmann. (Type); Pimelodella megalops Eigen- 
mann. (Type.) 
XVI. Pimelodella macturki Eigenmann. (Type) ; Pimelodus heteropleurus Eigen- 
mann. (Type.) 
XVII. Leptodoras linnelli Eigenmann. (Type); Trachycorystes obscurus (Giinther). 
(Type); Br achy platy stoma vaillanti (Cuvier and Valenciennes); Doras 
granulosus Valenciennes. 



Xlll 



XIV 



LIST OF PLATES 



XVIII. Leptodoras linnelli Eigenmann. (Type); Hemidoras microstomus Eigen- 
mann. (Type.) 
XIX. Hemidoras leporhinus Eigenmann. (Type) ; Hemidoras notospilus Eigen- 
mann. (Type.) 
XX. Centromochlus aulopygius Kner; Pseudauchenipterus nodosus (Bloch); 

Tympanopleura piperala Eigenmann. (Type.) 
XXI. Auchenipterus demerarce Eigenmann. (Type) ; Ageneiosus guianensis Eigen- 
mann. (Type.) 
XXII. Ageneiosus marmoratus Eigenmann. (Type) ; Helogenes marmoratus Gunther. 

XXIII. Hemicetopsis macilentus Eigenmann. (Type) ; Hemicetopsis minutus Eigen- 

mann. (Type.) 

XXIV. Hoploslernum littorale (Hancock); Hoplosternum thoracatum (Cuvier and 

Valenciennes) ; Corydoras punctatus (Bloch.) 
XXV. Plecostomus hemiurus Eigenmann. (Type); Pseudancistrus nigrescens 

Eigenmann. (Type) ; Ancislrus lilhurgicus Eigenmann. (Type.) 
XXVI. Plecostomus rvatwata (Hancock) ; Lithogenes lillosus Eigenmann. (Type) ; 

Neoplecostomus granosus (Cuvier and Valenciennes). 
XXVII. Corymbophanes andersoni Eigenmann. (Type.) 

XXVIII. Hemiancistrus braueri Eigenmann. (Type) ; Psexidancistrus barbatus (Cu- 
vier and Valenciennes.) 
XXIX. Lithoxus lithoides Eigenmann, cf (Type) ; Lithoxus Uthoides Eigenmann, 

9 and d\ Ventral surface. 
XXX. Loricariichthys microdon Eigenmann. (Type) ; Loricariichthys griseus Eigen- 
mann. (Type) ; Loricariichthys brunneus (Hancock) ; Loricariichthys 
platyurus (Muller and Troschel) ; Loricariichthys stewarti Eigenmann. 
(Type) ; Harltia platystoma (Gunther.) 
XXXI. Harttia platystoma (Gunther); Loricariichthys platyurus (Muller and 

Troschel) ; Loricariichthys brunneus (Hancock.) 
XXXII. Loricariichthys microdon Eigenmann. (Type) ; Loricariichthys griseus Eigen- 
mann. (Type) ; Farlowella hargreavesi Eigenmann. (Type.) 

XXXIII. Bivibranchia protractila Eigenmann. (Type.) 

XXXIV. Curimatus spilurus Gunther; Curimatus microcephalics Eigenmann and 

Eigenmann; Curimatus morowhannos Eigenmann. (Type); Curimatus 
issororoensis Eigenmann. (Type.) 
XXXV. Curimatus schomburgki Gunther ; Prochilodus maripicru Eigenmann. (Type) ; 
Tylobronchus maculosus Eigenmann. (Type) ; Chilodus punctatus Muller 
and Troschel. 
XXXVI. Parodon bifasciatus Eigenmann. (Type) ; He?niodus quadrimaculatus Pelle- 
grin; Hemiodus semitamiatus Kner; Nannostomus marginatum Eigenmann. 



LIST OF PLATES 



XV 



(Type); Nannostomus minimus Eigenmann. (Type); Nannostomus 
simplex Eigenmann. (Type.) 
XXXVII. Poecilobrycon harrisoni Eigenmann. (Type) ; Poecilobrycon Irifasciatus (Stein- 
dachner); Poecilobrycon erythrurus Eigenmann. (Type); Poecilobrycon 
ocellatus Eigenmann. (Type) ; Archicheir minutus Eigenmann. (Type) ; 
Characidium laterale Eigenmann. (Type and Cotype.) 
XXXVIII. Characidium vintoni Eigenmann. (Type); Characidium blennioides Eigen- 
mann. (Type) ; Characidium catena-turn Eigenmann. 
XXXIX. Characidium fascialum Reinhardt; Characidium pellucidum Eigenmann. 
(Type) ; Characidium pteroides Eigenmann. Type and Cotype. 
XL. Anostomus anostomus Linnaeus. 
XLI. Anostomus anostomus (Linnseus); Anostomus trimaculalus (Kner); Anosto- 
mus plicatus Eigenmann. (Type); Schizodontopsis laticeps Eigenmann. 
(Type.) 
XLII. Leporinus nigrotoeniatus (Schomburgk) ; Leporinus arcus Eigenmann. 

(Type.) 
XLIII. Leporinus allernus Eigenmann. (Type); Leporinus maculatus Miiller and 
Troschel; Leporinus granli Eigenmann. (Type); Leporinus friderici 
(Bloch.) 
XLIV. Poecilocharax bovallii Eigenmann. (Types c? and 9 ) ; Odontostilbe melandelus 
Eigenmann. (Type); Aphyocharax erythrurus Eigenmann. (Type); 
Aphyodite grammica Eigenmann. (Type.) 
XLV. Creagrulus melanzonus Eigenmann. (Type); Bryconamericus hyphesson 
Eigenmann. (Type); Pristella riddlei (Meek); Pristella aubynei Eigen- 
mann. (Type.) 
XLVI. Mamkhausia profunda Eigenmann. (Type) ; Fowlerina orbicularis (Cuvier 

and Valenciennes); Mamkhausia oligolepis (Giinther). 
XLVII. Ctenobrycon spilurus (Cuvier and Valenciennes); Moenkhausia grandi- 
squamis (Miiller and Troschel) ; Moenkhausia browni Eigenmann. (Type) ; 
Moenkhausia shideleri Eigenmann. (Type.) 
XLVIII. Hemigrammus unilineatus Gill; Hemigrammus erythrozonus Durbin. 
(Type) ; Hemigrammus rodwayi Durbin. (Type) ; Hemigrammus ocellifer 
(Steindachner) ; Hemigrammus orthus Durbin. (Type.) 
XLIX. Hemigrammus iota Durbin. (Type); Hyphessobrycon minimus Durbin. 
(Type); Hemigrammus cylindricus Durbin. (Type); Hyphessobrycon 
gracilis (Reinhardt); Hyphessobrycon minor Durbin. (Type); Hemi- 
grammus analis Durbin. (Type) ; Hyphessobrycon sticlus Durbin. (Type.) 
L. Hyphessobrycon rosaceus Durbin. (Type) ; Hyphessobrycon eos Durbin. 
(Type); Creatochancs affinis Giinther; Creatochanes melanurus (Bloch); 
Creatochanes caudomaculatus Giinther. 



XVI 



LIST OF PLATES 



LI. Astyanax guianensis Eigenmann. (Type); Astyanax essequibensis Eigen- 
mann. (Type) ; Astyanax mutator Eigenmann. (Type) ; Astyanax mucro- 
natus Eigenmann. (Type.) 
LII. Astyanax wappi (Cuvier and Valenciennes); Poecilurichthys polylepis 
(Giinther) ; Poecilurichthys abramoides Eigenmann. (Type) ; Poecilurich- 
thys potaroensis Eigenmann. (Type.) 
LIII. Deuterodon potaroensis Eigenmann. (Type) ; Deuterodon pinnatus Eigen- 
mann. (Type) ; Phenacogaster megalostictus Eigenmann. (Type) ; Phena- 
cogasler microstictus Eigenmann. (Type.) 
LIV. Holobrycon pesu (Muller and Troschel) ; Brycon falcatus Muller and Troschel ; 
Brycon siebenthalce Eigenmann. (Type.) 
LV. Chalcinus rotundatus (Schomburgk) ; Carnegiella slrigata (Giinther) ; Gastero- 
pelecus sternicla (Linnaeus). 
LVI. Serrasalmo rhombeus (Linnseus) ; Pygocentrus bilineatus Eigenmann. (Co- 
type) ; Caloprion mento (Cuvier) . 
LVII. Metynnis maculatus (Kner) ; Myloplus rubripinnis (Muller and Troschel) ; 

Myloplus asterias (Muller and Troschel), cf. 
LVIII. Myloplus rhomboidalis (Cuvier). 
LIX. Myleus pacu (Schomburgk) . 

LX. Exodon paradoxus Muller and Troschel; Roeboides thurni Eigenmann. 
(Type) ; Charax gibbosus (Linnseus) ; Asiphonichthys hemigramrnus Eigen- 
mann. (Type.) 
LXI. Acanthocharax microlepis Eigenmann. (Type); Heterocharax macrolepis 
Eigenmann. (Type) ; Acestrorhynchus falcatus (Bloch) ; Aceslrorhynchus 
nasutus Eigenmann. (Type.) 
LXII. Hoplias macrophthalmus (Pellegrin); Hoplias malabaricus (Bloch); Rhino- 
sardinia serrata Eigenmann. (Type) ; Stolephorus guianensis Eigenmann. 
(Type.) 
LXIII. Rivulus breviceps Eigenmann. (Type); Rivulus holmice Eigenmann, cf 
(Cotype), 9 (Type); Rivulus waimacui Eigenmann, d" (Cotype), 9 
(Type) ; Rivulus stagnatus Eigenmann, c? (Cotype), 9 (Type). 
LXIV. Rivulus lanceolatus Eigenmann. (Type); Rivulus frenatus Eigenmann. 
(Type); Poecilia vivipara Bloch and Schneider, d\ 9 ; Acanthophacelus 
melanzonus Eigenmann, c? (Type), 9 (Cotype). 
LXV. Acanthophacelus reticulalus (Peters), d\ 9 ; Acanthophacelus bifurcus 
Eigenmann, d" (Cotype), 9 ; Tomeurus gracilis Eigenmann, d 1 (Type), 
9 (Cotype) ; Nannacara anomala Regan. 
LXVI. Nannacara bimaculata Eigenmann. (Type); JFquidens potaroensis Eigen- 
mann. (Type); Geophagus surinamensis (Bloch). 
LXVII. Geophagus jurupari Heckel; Group of young. 



LIST OF PLATES 



XV11 



LXVIII. Heterogramma ortmanni Eigenmann. (Type); Heterogramma steindachneri 
Regan; Crenicichla alta Eigenmann. (Type.) 

LXIX. Cichla ocellaris Bloch and Schneider; Young, half-grown. 

LXX. Apionichthys unicolor Gunther; Soleonasus finis Eigenmann. (Type.) 

LXXI. Map : Distribution of the Aspredinidse. 

LXXII. Map : Distribution of the Pimelodinse. 

LXXIII. Map : Distribution of the Pimelodinse continued. 

LXXIV. Map: Distribution of the Pimelodinse continued. 

LXXV. Map : Distribution of the Doradinse. 

LXXVI. Map: Distribution of the Doradinse continued. 

LXXVII. Map: Distribution of the Auchenipterinse. 

LXXVIII. Map: Distribution of the Callichthyidse. 

LXXIX. Map : Distribution of the Plecostominse. 

LXXX. Map: Distribution of the Plecostominse continued. 

LXXXI. Map : Distribution of the Plecostominse continued. 

LXXXII. Map: Distribution of the Loricariinse. 

LXXXIII. Map : Distribution of Bimbranchia and Curimatus. 

LXXXIV. Map : Distribution of the Hemiodinse and Prochilodinse. 

LXXXV. Map: Distribution of the Nannostomatinse. 

LXXXVI. Map: Distribution of Charicidium of the Nannostomatinse. 

LXXXVIL Map : Distribution of the Anostomatinse. 

LXXXVTII. Map : Distribution of Leporinus. 

LXXXIX. Map : Distribution of Mamkhausia. 

XC. Map : Distribution of the Tetragonopterinse. 

XCI. Map: Distribution of Hemigrammus: 

XCII. Map : Distribution of the Tetragonopterinse continued. 

XCIII. Map : Distribution of Crealochanes. 

XCIV. Map: Distribution of the Tetragonopterinse continued. 

XCV. Map: Distribution of the Tetragonopterinse continued. 

XCVI. Map: Distribution of various genera of Characidae. 

XCVII. Map : Distribution of the Characidse. 

XCVIII. Map: Distribution of Characidse continued. 

XCIX. Map : Distribution of the Erythrininse. 

C. Map: Distribution of the Cichlidae. 

CI. Map: Distribution of the Cichlidse continued. 

CII. Map: Distribution of the Cichlidse continued. 

CIII. Map: Distribution of the Cichlidse continued. 



MEMOIES 



01' THE 



CAKNEGIE MUSEUM. 

VOL. V. NO. l. 

THE FRESHWATER FISHES OF BRITISH GUIANA, INCLUDING A 

STUDY OF THE ECOLOGICAL GROUPING OF SPECIES, 

AND THE RELATION OF THE FAUNA OF THE 

PLATEAU TO THAT OF THE LOWLANDS. 

By C. H. Eigenmann, Ph.D. 

INTRODUCTORY. 

I had two purposes in view in the trip to Guiana: first, to observe, photograph, 
and incidentally collect as many species as possible for my monograph of the 
characins; second, in connection with my general faunal study of the fishes of 
South America to determine, if possible, the relation of the fish-fauna of the Guiana 
plateau to that of the lowlands, more particularly the relationship existing between 
the faunas of the upper and the lower Potaro. The two reaches of the PotarO are 
separated from each other by the Kaieteur Fall, over which the water leaves the 
Guiana Plateau by a drop of seven hundred and forty-one feet. Although all 
other things were sacrificed to the two purposes mentioned, I cannot claim that 
I accomplished them to my entire satisfaction. The conditions were all so novel, 
the difficulties of travel so great, the heat so intense, the fauna so rich, the 
time and the money at my command so limited, that I now occasionally regret 
that at this or that point I did not use different means, or devote more time to 
the objects in view. But to offset this regret I have many solid satisfactions. 

If seeing and recording a lot of "specimens," which have been disintegrating 
for longer or shorter periods in alcohol, can be called acquaintance, I have been 
acquainted with South American fresh-water fishes for many years. In contrast 



2 MEMOIRS OF THE CARNEGIE MUSEUM 

to such an acquaintance I recall standing one exciting morning on the brink of a 
small pool, which my Indians said contained fishes. It was not more than fifty 
feet across and was back-water left by the receding Essequibo. The Indians 
pounded poisonous hiari roots, tied them into bundles, and the boys then swam 
through the pool with them over their backs, and thus mixed in the poison. Soon 
one species, then another, and still others, which I had only known as mummies, 
were resurrected from the depths of that pool, and I danced about its margin with 
delight to see them in their vivid living colors and incidentally to embalm them 
in their turn for future reference. On another glorious working day, which lasted 
from 6 A.M. to 12:30 A.M. of the day following, I secured over seventy species of 
fresh-water fishes, more than forty of which were characins. 

Robert Schomburgk noted eighty-three species of fishes in his travels about 
Guiana, only thirty of which came from the region covered by this paper. I secured 
more than twice as many species in a few hours. Richard Schomburgk reported 
a total number of one hundred and forty-eight species, of which about eighty 
were recorded from the area covered by this report. In all, only one hundred 
and sixteen species have been hitherto recorded from the rivers of British Guiana, 
discharging into the Atlantic, while three hundred and sixty species are 
recorded in the present paper. Of these 1 myself collected all but twenty- 
seven. Of the twenty-seven species I have examined all but Rhamdia laukidi, 
Rhamdia arekaima, and Pimelodus altipinnis. Rhamdia laukidi and arekaima are 
probably forms of R. clarias. No one has seen them since Schomburgk's day, and 
he did not preserve specimens. Pimelodus altipinnis was described from a small 
specimen said to have come from Demerara. The species said to be P. altipinnis 
is abundant in the lower Amazon. 

With the exception of the few cases in which labels were lost in transit, all of the 
specimens here recorded are assigned to exact localities. Very few definite localities 
had been previously put on record. "Demerara," "Essequibo," "Rupununi," 
or "British Guiana," have been the usual designations. Nannostomus beckfordi 
Giinther and Heterogramma steindachneri Regan are among the few species the 
definite habitats of which were known. 

Science owes a debt to a number of persons in and out of Guiana, who 
very generously assisted me in various ways. The officers of the Quebec 
Steamship Co., Ltd., transported our collecting outfit and our collections free of 
all charge, and made generous reductions from the regular passenger tariff from 
New York to Georgetown and return. Messrs. Sprostons, Ltd., conveyed us and 
our baggage free to all points within the colony reached by their boats, and put 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 3 

us under still greater obligations by instructing their various agents to help us in 
every possible way. The officers of the railway between Georgetown and New 
Amsterdam gave us similar help. Mr. Lyman Jones and Mr. St. Aubyne of the 
Lama Water Conservancy placed boats, a house, servants, and a number of men 
at our disposal, and the collections from Lama Stop-Off, Maduni Stop-Off, and 
Cane Grove Corner are altogether due to the disinterested help of these gentlemen. 
The most generous interest in the success of the expedition was displayed by Dr. 
Edwin Bovallius and Mr. George Linnell, who furnished me with boats and a 
crew of sixteen Indians, who conducted me from Kangaruma to the Chenepowo 
River at Holmia and to the Aruataima Cataract. Mr. William Grant, the Indian 
guide and interpreter on this trip, became an enthusiastic fisherman, and has sent 
me many new things since my return. 1 At Holmia the quarters of the Essequibo 
Exploration Company were placed at my disposal, and here I was able to recuperate 
from a fever, while my crew were gathering poison and fishes. The success in the 
upper Potaro is entirely due to the generous help of Messrs. Bovallius and Linnell. 
At Tumatumari Mr. Brummel, at Wismar Mr. J. D. Spence, and at Georgetown 
Messrs. J. B. Mitchell, James Rodway, C. W. Anderson, E. A. V. Abraham, and 
Professor J. G. Harrison aided me in various ways. Mr. B. S. Conrad of George- 
town, to whom I had a letter of introduction, greatly assisted the expedition with 
advice and guidance. He not only generously devoted much of his own valuable 
time to the interests of the expedition, but introduced mc to other gentlemen, who 
aided me in a variety of ways. I am indebted to Mr. E. S. Shideler, who acted as 
volunteer student assistant on this trip. He collected with me most of the time, 
and the collections from Malali, Bartica, the Botanic Garden, and the northwest 
are entirely due to his efforts. 

The summer of 1910 was devoted to examining the types of fishes from Guiana 
in European museums. Drs. G. A. Boulenger and C. T. Regan of the British 
Museum, Drs. Th. W. van Lidth de Jeude and C. M. L. Popta of the Leyden 
Museum, Director Dr. Max Weber of the Amsterdam Museum, Director Dr. A. 
Brauer and Dr. P. Pappenheim of the Royal Museum in Berlin, Intendant Hofrat 
Dr. Fr. Steindachner of the K. K. Naturhistorisches Hofmuseum in Vienna, and 
Dr. J. Pellegrin of the Musee d'Histoire Naturelle in Paris all cordially cooperated 
by placing the types in their keeping at my disposal. 

1 Mr. Grant collected in the following places not reached by me: Nickaparoo (or Nickaparu) Creek, 
branch of the Ireng; Maripicru, a branch of the Ireng between Wontyke and Karakara, above the Karona 
falls; Chipoo, a tributary of the Ireng between Karakara and the Rupununi; Papan, near Eworora; Twoca 
Pan, between the Rupununi and Pununike; Rupununi, opposite Massara Landing; creek between Rapoo and 
the lower falls; Packeoo should possibly be "Pacu" Falls, in the Rupununi; Gatuck Creek, Potaro Highland; 
Yakeatonuk Fall, Potaro River. Some of these names are spelled in several ways on the different labels. 



4 MEMOIRS OF THE CARNEGIE MUSEUM 

Most of the drawings illustrating the paper were prepared by Mr. W. S. 
Atkinson of Stanford University. The photo-drawings are for the most part the 
combined work of Professor W. Cogshall of Indiana University, Miss Maud Sie- 
benthal, and myself. The final arrangement of the figures on the plates was the 
work of the Editor, to whom I am indebted for much other kind help and crit cism. 

In the preparation of the account of the Ariince I had the assistance of Mr. 
Owen Frazee. Mr. Elmer Deem assisted with the Doradince, and Miss Lola Vance 
with the Pimelodince. The account of the Gymnotidce was prepared by Dr. Max 
Ellis. I have given no figures of the Gymnotidce, having reserved these for the 
monograph of the family by Dr. Ellis, which is ready to go to press. The Scicenidce 
were described by Mrs. Marian Durbin Ellis, and the accounts of Hemigrammus 
and Hyphessobrycon are extracted from the monograph of these genera by Mrs. 
Ellis, which is still in manuscript. 

Mrs. Rosa Smith Eigenmann has been of the greatest assistance in the prepara- 
tion of this paper. Deprived of the pleasures and responsibilities of more formal 
collaboration, she has critically read the manuscript and overseen the work of the 
artists. 



CHAPTER I. 

BRITISH GUIANA. 

In speaking of the country I cannot do better than to reproduce in part the 
excellent account from the pen of Wilgress Anderson, F.R.G.S., contained in a 
work upon the goldfields published a couple of years ago by Mr. J. B. Harrison. 
The pages of the original are indicated in brackets: 2 

General Physical and Topographical Features of British Guiana. 

[p. 9.] "Situation and Extent. — The region called Guiana, or Guyana, stretches 
along the northern coast of South America from the mouth of the Orinoco River 
to that of the Amazon River, and inwards to Brazil. . . . 

" The only European possessions in South America are three in number, and 
are situated on the central portion of this territory, which is divided into the colo- 
nies of the British, Dutch, and French Guiana. 

" Of these colonies, the most westerly is that of British Guiana, which extends 
from the eastern limits of Venezuela, westward to Dutch Guiana, and north of 
Brazil to the coast on the Atlantic Ocean, its extreme limits touching the parallels 
of 0° 41' and 8° 33' 22" north latitude, and the meridians of 56° 20^' and 61° 23' 
24.7" west longitude. 

" British Guiana has a seaboard of about 270 miles trending in a southeasterly 
direction, with a mean depth of about 500 miles, and is equal in extent to the com- 
bined size of England, Scotland and Wales, the area being about 90,000 square 
miles, most of wdrich is densly covered with exuberant primeval forest, but in some 
parts there are broad open flats and undulating grassy plains, or savannahs, and 
mountainous grass-clad country. 

"Physical Features. The Alluvial Belt. — The colony may be divided broadly 
into two low-lying belts near the coast and a hilly and mountainous hinterland 
which constitutes by far the largest area. 

"The coast-lands are flat and for the most part swampy, being slightly de- 
pressed below the level of ordinary spring-tides, so that sea-walls and other defences 

2 The Geology of the Goldfields of British Guiana, by J. B. Harrison, 8vo, pp. i-ix, 1-320, 43 plates. London, 

Dulau & Co. 

5 



b MEMOIRS OF THE CAENEGIE MUSEUM 

have to be constructed to protect the settled parts of the coast-lands from being 
flooded by high tides. They form part of an alluvial belt which rises gradually 
from the sea-level and extends inland for a distance varying from ten to forty 
miles, and which is composed of variously colored clays with intermediate layers 
of sand and peat, the latter being locally known as pegass. 

"The margins of this formation along the sea and rivers are covered with a 
dense growth, consisting principally of mangrove (Rhizophora mangle) and of 
courida (Avicenna nitida), which form natural sea-defences, the former being found 
along the western and the latter along the eastern parts. Behind this growth are 
flat grassy savannahs [p. 10] interspersed with forest, consisting mostly of Aeta 
and Trooli palms (Mauritia fiexuosa and Manicaria sacdfera), whilst in some parts 
the land is covered with a dense jungle. It is on this belt that all the sugar estates 
and by far the greater part of the cultivated areas are situated. 

" The Sand and Clay Belt. — The alluvial belt is succeeded by a slightly elevated 
and undulating belt composed of sandy and clayey sedimentary soils, derived 
from the disintegration of the various country rocks in situ, and traversed in some 
places by sand-dunes, which rise from fifty to about one hundred and eighty feet 
above the sea-level. This second belt commences at the Waini River, in the north- 
western district, and gradually increases in width as it extends toward the eastern 
boundary of the Courantyne, in the vicinity of which it attains its greatest depth 
at about one hundred miles inland. Grass-covered downs occur on the banks of 
the Berbice and Courantyne Rivers, but the greater part of this tract consists of 
high forest, and along the river margins and in the valleys mora trees (Dimorph- 
andra mora) grow plentifully. 

"The Hinterland. — Beyond these belts, southward, the country rises between 
the river valleys, which are in many parts swampy, and as it approaches the 
sources of the larger rivers attains a height of about nine hundred feet above the 
sea-level at the source of the Takatu, the western boundary, and about four hundred 
feet above the sea at the source of the Courantyne, the eastern boundary. This 
more elevated portion occupies about eleven-twelfths of the area of the colony. 
It is diversified by numerous low hills and valleys, and contains three principal 
mountain ranges, several irregularly distributed smaller ranges, and in its southern 
and eastern parts many scattered isolated mountains, none of the last mentioned 
being more than fifteen hundred feet above sea-level. 

"The eastern portion is almost entirely forest-clad, yet the country on the 
western side of the colony, between the Rupununi and Ireng Rivers and extending 
southwards from the Pakaraima Mountains to the Kanuku Range consists of an 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 7 

almost flat grass-clad plain or savannah, elevated about three hundred feet above 
sea-level, in which, in the vicinity of and bordering upon the many streams by 
which it is watered, are patches of woodlands. From the Kanuku Mountains 
southwards to about six miles from the source of the Takutu and from that river 
eastwards to a considerable distance beyond the Rupununi there is an extensive 
and undulating elevated savannah with similar patches of woods along the valleys 
of the many streams by which it is drained. Beyond this the extreme southern 
part of the colony is entire'y forest-clad. 

[p. 11.] "Rivers. — Of the numerous river-systems there are six principal ones, 

viz.: — 

(1) The Essequibo and its principal tributaries, the Mazaruni and Cuyuni; 

(2) The Courantyne and its tributary, the New River; 

(3) The Berbice and its tributary, the Canje; 

(4) The Waini and its tributary, the Barama; 

(5) The Demerara; 

(6) The Barima. 

"These, together with the following smaller ones, the Abary, Mahaicony, 
Mahaica, Boerasirie, Pomeroon, and Maruka Rivers, flow to the Atlantic Ocean. 

"In addition to the above mentioned rivers, there are the Takatu and its 
tributary, the Ireng, which meet together at 3° 34' north latitude and form the 
Brazilian boundary. The Takuta River flows thence to the Rio Negro, the waters 
of which join the Amazon. 

"The Essequibo, the largest river in the colony, rises in 0° 41' north latitude, 
about eight hundred and fifty feet above the sea-level and flows in a northerty 
direction for some six hundred miles. It is joined at Bartika, about forty miles 
from its mouth, by the Mazaruni River, a tributary, which is itself joined at 
Cartabo, five miles above Bartika, by another tributary called the Cuyuni River, 
all these combining to form an estuary with a width of about three miles below 
their junction, and which expands to a width of fourteen miles at the mouth, con- 
taining, as it approaches the sea, three islands, each of which is about twelve miles 
in length, and in addition many smaller ones. The river is navigable for large 
vessels as far as Bartika, and for small launches to the foot of the first rapids, 
eighteen miles above that point. Beyond this its course is broken by many rapids 
and cataracts, and about five miles above the junction of the Rupununi the Esse- 
quibo river is practically unnavigable on account of the many long series of cataracts 
and falls, which obstruct its course. 

[p. 12.] "The Rupununi River joins the Essequibo in 4° 2' 52" north latitude, 



8 MEMOIRS OF THE CARNEGIE MUSEUM 

and gives access during the rainy seasons to the elevated grass-clad plains, or 
savannahs, on which at the present time a large number of cattle are being raised. 
During the height of the dry seasons the river becomes very shallow, its course 
being impeded by many sandbanks and rapids, and during this time it can only 
be ascended with great difficulty and much loss of time, or rather not at aU. Its 
many inlets and large lake-like ponds on both banks form a feature common also 
to the upper parts of the Berbice River. Its largest tributary is the Rewa, or 
Illiwa, which is itself joined by the Quitaro, and both flow through country covered 
with high forests." 

[p. 14.] "The Demerara River, although commercially the most important and 
best known of all the rivers in the colony, is, compared with some of those already 
described, a small one. As the greater depth at the bar admits of large vessels 
entering this river with more security and ease than is the case with any of the 
other rivers in the colony, Georgetown, the capital and principal port of the colony, 
hSs been established on its east bank at its mouth, which is there three-quarters 
of a mile wide, and furnishes a safe harbor for the many steamers and sailing vessels 
which frequent the port. The Demerara River takes its rise in the small mountain- 
range called the Maccari, which is really an offshoot of the great Pakaraima range. 
It has a generally northerly course, and flows between the Essequibo and the Berbice 
Rivers. The river is navigable for steamers for nearly eighty miles upwards from 
its mouth, and beyond this for launches for about twenty-four miles further up, 
as far as the Malali Rapids, where the influence of the tide ceases. Above Malali 
the river is again navigable for launches as far as Kanaimapoo, above which are 
the Kumaparu Rapids, where the Demerara River approaches nearest in its course 
to the Essequibo River. The first great cataract on this river is situated a short 
distance above Kamaparu, in latitude 5° 18' north, and is known as the Oruru- 
Malali, or Great Falls. Beyond Oruru-Malali the river is sluggish, and is again 
navigable for boats as far as the Cannister Cataracts, where it divides into two 
streams. Its forest-clad banks are flat as far up as the second or sand and clay belt, 
where the sand hills occur and form the first high land." 

"Mountain Ranges. — One of the most prominent features of the country is the 
great central mass of mostly flat-topped mountains, known as the Pakaraima group 
or chain, which occupies the most western [p. 15] portion of the colony, and stretches 
southward from the Cuyuni River to within thirty miles above the mouth of the 
Ireng River, and eastward to the Essequibo River right across the colony as far 
as the Courantyne River." 

"The bulk of these mountains forms a successive series of terraces and broad, 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 9 

undulating plateaus, with bold, and in some cases, perpendicular sandstone escarp- 
ments, varying in height from about twelve hundred to over two thousand feet, 
and eventually forming a large undulating table-land at an average height of about 
thirty-five hundred feet above the sea-level. In many parts of the mountains and 
table-lands great and deep gorges have been eroded by the rivers and streams 
which traverse them. They attain their greatest height at Mount Roraima and 
Mount Kukenaam, both of which rise over eight thousand five hundred feet above 
the sea. The portion of this range which extends westward and down the southern 
bank of the Mazaruni River to the vicinity of the Teboco Cataracts retains the 
striking flat-topped features and is known as the Merume Mountains." 

"The elevated table-land (8635 feet) of Mount Roraima is about twelve square 
miles in area, and on it the boundaries of the colony with those of Venezuela and 
Brazil meet at a common point. This very remarkable mountain, together with 
Mount Kukenaam, is a part of one of the most extensive sandstone formations 
on the globe, and they both rise with perpendicular cliffs of sandstone two thousand 
feet in height above the base of the surrounding country." 

"The highest plateaus, such as Mount Roraima, are mostly bare, exposed 
expanses of rock, between the crevices of which grow many rare and curious orchids 
and other flowering plants, besides some low bushes and extremely stunted trees." 

General Geology. 3 
[p. 19.1 " The Coast-Lands. — The alluvial deposits are of considerable, but 
unknown thickness. As they rest upon beds of pipe-clay or impure kaolin it is a 
matter of great difficulty to decide whether the borings for underground waters, 
which have from time to time been made in various parts of the coast-lands, have 
been wholly in the alluvium, or have, as they certainly have done in some cases, 
penetrated through these beds into the underlying residuary clays. In places, 
however, the alluvial deposits have been proved for depths of over two hundred 
feet, and it is possible that in many places their thickness far exceeds this. The 
cores of the borings show that the alluvial deposits consist of beds of more or less 
indurated marine muds and sands which have been laid down so as to form beds 
of clay, of mixed clay and very fine siliceous sand, locally known as 'caddy.' and 
of siliceous sands varying much in texture — some beds consisting of sand of ex- 
tremely fine texture, others of coarser grain, while others again approach in char- 
acter fine grits or gravels. In places some of the beds contain considerable quantities 

3 The notes upon the Geology are derived from the same work hitherto quoted, and from the pen of 
Mr. J. B. Harrison, the Government Geologist of British Guiana. 



10 MEMOIRS OF THE CARNEGIE MUSEUM 

of decomposing vegetable debris, and these, when drilled into during deep well- 
sinking operations, in some cases give off inflammable mixtures of gases containing 
marsh gas in considerable quantities. In places the effusion of the gases has been 
accompanied by that of small quantities of petroleum, a decomposition product of 
the organic matters. The geological age of these beds is uncertain, the lower parts 
may be of late Tertiary or Pleistocene age, while the parts now bordering the coast- 
line are undoubtedly recent. I am inclined to think that their age is, in part at 
least, similar to that of the Moruga sands of Trinidad. The sand-beds of these 
deposits are not unfrequently exposed in the cultivated parts of the coast-land, 
where they are known as sand-reefs. These form in places oval patches of land 
raised a few feet above the general level of the surrounding [p. 20] argillaceous 
soils, and in many others gives rise to long narrow ridges somewhat raised above the 
general level of the land which they traverse. Their mode of occurrence indicates 
that they are purely local modifications of the alluvial deposits, — sands separated 
from the mass of the marine silt by the action of local currents and of the waves,— 
and thus the sand-beds form more or less lenticular beds occupying, as a rule, no 
great area. They are, in my opinion, very distinct from the beds of sand which 
characterize various phases in areas where the land is either rising or falling to any 
extent in the vicinity of a shallow sea. 

" The general evidence indicates that British Guiana occupies one of the most 
stable areas of the earth's surface, — one which has been very slowly rising through long 
ages* — this slow movement having given rise to the low rapids which usually 
mark the termination of the tide-way in the rivers, and possibly which has so 
altered the contour of parts of the continent on which the colony is situated as to 
change the main lines of drainage, and thus to make the rivers relatively small 
streams traversing the deeper parts of the courses and valleys eroded by their 
predecessors in earlier periods. During a stage in this slow upheaval the low hills 
already mentioned as occurring in a few places in the alluvial coast-land were in 
turn rocks and small islands in the shallowing sea which then surrounded them, as 
now they are surrounded by an apparently unbounded expanse of forest or of 
marsh. 

"A remarkable feature in parts of the alluvial coast-land is the occurrence of 
extensive beds of a kind of peat. This is locally known as 'pegass,' and consists 
of the more or less altered remains of ferns, mosses, and sedges, and of other marsh- 
loving plants. It resembles in its general character the upper layers of the vegetable 
matter which are found in peat-bogs in temperate climates. As far as my observa- 

* The Italics are mine. C. H. Eigenrnann. . . 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 11 

tions go it is never as compact as true peat. This is probably due to the deposits 
of it being seldom more than from two to four feet in thickness. 

"As pointed out by Sir Charles Lyell in his 'Principles of Geology,' a large 
portion of the sand and clays of the alluvial deposits has been brought by the cur- 
rents from the mouth of the Amazon River; the burden brought by the present 
rivers of the colony from the higher districts through which they flow having been, 
during recent periods, a very subordinate factor in the accumulation of this wide- 
spread formation; although perhaps in earlier times, before the land had risen to 
its present level, the river-borne silt may have contributed a large quota to the 
mass. 

"The Forest Lands and Residuary Deposits. — The alluvial strata extend to 
depths varying from five to, in places, as much as thirty-five miles from the coast- 
line and rest upon beds described by C. B. Brown as 'sand and clay deposits.' " 

[p. 21.] "These residual deposits cover and hide the true country over vast 
areas of the lower-lying parts of the colony, and form the characteristic sub-soils 
and soils of our forest regions. 

"The parts of the areas covered by these residuary deposits which abut upon 
the true alluvial beds are in many places traversed by long ranges of sand-dunes, 
giving rise to low hills, which, as in the case of the range traversed by the Demerara- 
Essequibo Railway, may attain a height of somewhat over two hundred feet. As 
a rule, their heights do not exceed one hundred or one hundred and twenty feet. 
The sand, of which the upper parts, at any rate, of these dunes (it is possible that 
in many cases they cover ridges of the residuary deposits) consist, is glistening, 
white, quartz sand, the grains of which are usually uniform in size over relatively 
large areas, the majority being well rounded, thus accentuating the wind-blown 
origin of the dunes. 

"C. B. Brown notices that the beds form a low escarpment at the southern 
limit of the fluvio-marine deposit, and that this has been taken for a ridge running 
parallel to the coast. I have not had opportunities of repeating this observation, 
but, accepting its accuracy, I consider that the ridge approximately marks the shore- 
line, which existed at the commencement of the deposit of the present fluvio-marine 
[p. 22] alluvium. Observations made in the forest regions since the time of Brown's 
geological reconnaissances of the interior of the colony have shown that the resid- 
uary deposits cover the country not alone on the plains of the lowlands, but along 
the great river-valleys and on the lower forest-covered parts of many of the hills 
and mountains. The heavy, at times torrential, tropical rains have carved out 
of the residuary coverings deep ravines and valleys; and the gravels, sands, and 



12 MEMOIRS OF THE CARNEGIE MUSEUM 

silts derived from the eroded material have been laid down in the wide valleys 
along the courses of parts of the rivers as fluviatile loams, gravels, and sands. 

" The Sandstone and the Diabase Intrusions. — Large areas of the interior of the 
colony are occupied by a thick stratified formation of sandstone and conglomerate. 
Just as the basal igneous rocks are, so is this, pierced and traversed by dykes of 
diabase, hence the latter rock must be of later origin than all except the sedimentary 
coverings and the fluvio-marine deposits. The blue-grey rock varies much in depth 
of color and texture, and its varieties will be described in the chapters dealing with 
the petrography of the colony. 

"The diabase intrusions occur in belts, generally stretching across the colony 
in a north-westerly and south-easterly direction. The intrusions vary from narrow 
dykes, only exposed in the courses of the rivers during very dry seasons, some being 
not more than from two to three feet across, to low hills and to mountain ranges, 
some of which — for example, the Eagle mountains in the Potaro gold district — 
exceed in height two thousand feet. The tops and sides of the hills and mountains, 
except where they have suffered great denudation, are covered with ironstone gravel, 
while the lower parts of the district in which diabase forms the [p. 23] country are 
covered up with strata of laterite, frequently over one hundred feet in depth, and 
in places interspersed with nests of secondary quartz, or traversed by veins and 
stringers of quartz, or, less often, by lenticular layers of secondary quartz, closely 
resembling, when cut through by mining shafts, tunnels and trenches, — true quartz- 
reefs. The quartz rock in all these forms is not unfrequently auriferous, the metal 
being dispersed through it in a very irregular manner, especially in the large lenticu- 
lar layers, which in many parts are nearly, or even entirely, barren of gold, and in 
others are "bonanzas" carrying at rates from twenty to, in places, several hundred 
ounces of the precious metal to the ton of the rock. Unfortunately hitherto these 
bonanzas have proved few and far between; but there is no reason for assuming 
that they will not be found in many places in the enormous area of the laterite 
deposits which up to the present has not been prospected, as they have been in 
similar places at intervals in the past. Gold also occurs as paint gold, as gold dust, 
and as nuggets of very varying sizes in the laterite. 

"Of earlier age than the diabase is the sandstone and conglomerate series. 
It constitutes the greater portion of the Pacaraima mountains, and spreads west- 
wardly into Venezuela. A similar formation occurs in Brazil, and in all probability 
is part of the same massif as the Guiana one. Wherever it occurs it appears to 
be unfossiliferous, and hence we have no paleontological evidence with regard to 
the geological period at which it was deposited. Two conjectures have been made 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 13 

as to this. C. B. Brown arrived at the conclusion on what appears to me to be 
somewhat defective evidence (its, in parts, reddish color, its unfossiliferous nature, 
and its being penetrated by masses, dykes, and sills of greenstone — diabase — as 
are sandstones of Triassic age in North America), that it is an equivalent of the 
New Red sandstone. In Venezuela its relationship to rocks of known age is said 
to be recognizable, and it is stated to be of Cretaceous age. A like conclusion that 
the northern parts of the format'on are of Cretaceous age has been arrived at in 
Brazil. If these views are correct, the later outbreaks of diabase, which are, directly 
or indirectly, the causation of many of the auriferous deposits of British Guiana, 
must be either of Cretaceous age, or belong to the Tertiary or to a later period. 
And as there is a very great resemblance in the magmatic character of the Guianan 
diabase, and of the lavas of the West Indian province, whose outbreaks are clearly 
of Tertiary and of present age, the assumption of the relatively recent age of the 
diabase is a plausible one. As will b? mentioned in a later chapter, the diabase 
shows no signs of the effects of the regional metamorphism which has materially 
affected many of the rocks underlying the sandstone formation. 

"The only evidence available in this colony with regard to the sandstone and 
the geological period of its formation is that wherever its base has been seen it 
occupies an analogous position to the Torridonian sandstones of the Scottish High- 
lands, to which the sandstone has a close resemblance in constitution. It lies 
invariably on the presumably Archean rocks of the colony; and its constituents, 
as far as I have been [p. 24] able to examine them, show no signs of having, even in 
part, been derived from later rocks. If it is of Cretaceous age it offers an interesting 
example of the recurrence of similar formations in widely divided geological ages, 
when the conditions affecting their formation and deposition are identical. Per- 
sonally I am not prepared from my own observations and studies to accept any 
statements of its geological age further than that shown by its relationship to the 
underlying gneiss, porphyries, felsite and schists derived from them. 

"The sandstone formation spreads eastwardly through the colony, crosses the 
Essequibo River in a low narrow belt at Comuti Mountain, gives rise to the Maccari 
Mountain in Demerara, and crossing the Berbice River near Marlissa Rapids, is 
seen forming a low mountain range at Itabru near that river. It passes into Dutch 
Guiana across the Courantyne River near its union with the Cabelebo River, and 
also in its higher reaches. The formation consists of beds of coarse conglomerate, 
red and white sandstones of very varying textures, and in places of strata of red 
shale. 

"High mountains occur in the sandstone formation, which consist of coarse 



14 MEMOIRS OF THE CARNEGIE MUSEUM 

textured diabase or of rather fine-grained gabbro. This rock shows signs of meta- 
morphism, in places being granulitic in structure and in others being changed to a 
considerable extent, either by the development in it from augite of a dark-brown 
secondary biotite, or the pyroxene is altered from an almost colorless mineral to a 
brown-colored strongly dichroic one. 

"Mr. C. Wilgress Anderson, who in 1895 spent several months in traversing 
the sandstone district while nquiring into the alleged occurrence of beds of aurifer- 
ous conglomerate in it, and has since crossed it repeatedly during the Boundary 
Surveys, is of opinion that the diabase gabbro is of greater age than the sandstone, 
the latter formation in places resting on or abutting against it, and this view is 
upheld by its structure. The hills were probably small islands in the shallow seas 
in which the sandstone formation was laid clown. C. B. Brown, on page 14 of the 
'Reports on the Geology of British Guiana,' mentions the occurrence of great 
layers of conglomerate in the neighborhood of 'greenstone,' and this is confirmatory 
of Mr. Anderson's view. The possible existence of 'greenstone' of two distinct 
geological ages and modes of occurrence does not seem to have struck Brown and 
Sawkins, but it offers an intelligible explanation of the facts recorded by them in 
their reports. These surveyors estimated the total thickness of the sandstone on 
the assumption that it is traversed by three layers of greenstone at about three 
thousand feet. As, however, it is probable that some at least of the latter diabase, 
as, for instance, that at Roraima, is in the form of laccolites, and during intrusion 
has elevated great tracts of the sandstone country, probably the formation has not 
the total thickness deducible from C. B. Brown's figures, and may at present not 
anywhere exceed in thickness that shown at Roraima — about two thousand feet. 
As a rule the sandstone lies nearly horizontally, dipping somewhat to the north, 
and few faults are seen in it, although in places near where diabase has intruded 
into it [p. 25] there are well-marked local disturbances in its dip. Many of the 
beds of sandstone of finer texture show well-marked current-bedding." 



CHAPTER II. 

EARLIER WORKS ON THE FISHES OF BRITISH GUIANA. 

The first notice of the fishes of the area covered by this report, which I have been 
able to discover, is Van der Lott's "KortBericht von den Congeraal, ofte Drilvisch," 
Verhandl. Holl. Maatsch., Harlem, 1762. Van der Lott was at the time a surgeon 
on the Essequibo, who attributed so many "medical properties" to the electric 
eel that he "acquired no increase in reputation therefrom in this colony," as Ban- 
croft says. 

In his "An Essay on the Natural History of Guiana," London, 1769, Edward 
Bancroft publishes a letter dated "Demerary, Aug. 15, 1766," in which he mentions 
or describes (p. 188) the "Lowlow," the "Bafroketa" (Arapaima?), (p. 189) "Pen" 
(Serrasalmo?) , (p. 190) "Saw-fish, Flounders, Brasilian Soles, Surinam Mackarel, 
Drummers, Old-wifes, Mullets, and a species of Anchovies." 

He devotes several pages, 190-202, to the "torporific eel," attributing the 
shock to electricity. This was several years before Hoist (1772) demonstrated 
that the peculiar power of the torpedo is due to electricity. 

Hillhouse in his "Indian Notices," a book which I have not seen, is said to 
enumerate " wenty-six species as peculiar to the coast, estuaries, and rivers of 
Guiana." 

Hancock in his "Notes on some species of Fishes and Reptiles from Demerara, 
presented to the Zoological Society by John Hancock" (Zoological Journal, Vol. 
IV, pp. 240-247, 1829; also I sis) describes: 

Doras costatus = Doras hancockii Cuv. & Val. 

Callichthys littoralis = Hoplosternum littorale (Hancock). 

Hypostomus watwata = Plecostomus watwata (Hancock). 

Hypostomus muUiradiatus = Pterygoplichthys vndtiradiatus (Hancock). 
Loricaria brunnea = Loricariichthys brunneus (Hancock). 

But the first real work in gathering fishes and knowledge concerning them 
began with the explorations of Robert Hermann Schomburgk, conducted during 
the years 1835-1839 under the auspices of the Royal Geographical Society and the 
British Government. The explorations were continued by Robert Hermann 

15 



16 MEMOIRS OF THE CARNEGIE MUSEUM 

Schomburgk and his brother, Richard Schomburgk, during the j^ears 1840-1844. 
Robert in the second expedition went as an explorer for the British Government. 
Richard Schomburgk was sent along by the king of Prussia at the instigation of 
Alexander Von Humboldt. 

Robert H. Schomburgk during his first expedition collected but few specimens, 
to which we may now refer. But he had many drawings made and furnished notes 
concerning the species drawn. The notes were edited, the drawings named, and 
the whole published by Jardine as "Fishes of British Guiana," Parts I and II, 
forming Volumes XXXIX and XL of "The Naturalists Library." 

Schomburgk not only explored the rivers flowing northward, but made a long 
tour across the head of the Orinoco, down the Rio Negro, and up the Rio Branco. 
Fifty-three of the eighty-three species noted in the volumes seem to have come 
from the basin of the Rio Negro, only thirty being definitely ascribed to streams 
flowing northward. 

I long ago expressed the opinion that some of the drawings are composites, 
and that in some cases a wrong combination of figure and description was made 
by the editor. 4 Nevertheless the two little volumes form a notable contribution 
to the knowledge of the fishes of Guiana. Schomburgk presented to the Jardin 
des Plantes and to the British Museum several specimens, which were made the 
types of new species. Whether they were collected during his first or second 
expedition I do not know. 

Schomburgk's first journey was described in his "Reisen in Guiana und am 
Orinoco wahrend der Jahre 1835-1839," published by O. A. Schomburgk, Leipzig, 
1841. The journey was divided into several longer or shorter excursions. 

1. He left Georgetown September 21, 1835, and ascended the Essequibo to 
the Cuyuni, up which he went a short distance, and then continued on up the Esse- 
quibo to the Rupununi and up this river to near its source. He then returned to the 
Essequibo and went up this stream to the William IVth Cataract, then down to the 
Siparuni, up which he went some distance, returning March 28, 1836, to Georgetown. 

2. On September 2, 1836, he again left Georgetown and ascended the Couran- 
tyne to some large cataracts. 

3. On November 25th he started up the Berbice River and went to the parallel 

4 Schomburgk's difficulties may be appreciated from liis statements, Vol. I, 82-83: "But with the ex- 
ception of my Indian friends and Dr. Fleming's Philosophy of Natural History I had nothing to guide me in 
my researches" and "The first specimen of any fish, a drawing of which we did not previously possess, served 
generally to sketch its outward forms and general colors on the paper; and when we were fortunate enough 
to secure a second specimen those delicate hues were painted in, which are only visible immediately after the 
fish comes out of the water." 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



17 



of the junction of the Rupununi and Essequibo and started over to the Essequibo 
and returned by way of the Berbice. 

4. On September 12, 1837, he again ascended the Essequibo and Rupununi 
to the Rewa, up which he went and crossed over to the Cuyuwini, an upper tribu- 
tary of the Essequibo. He descended it to the Essequibo, which he ascended to its 
source. He then returned to the Rupununi about Lake Amucu, 6 whence he went 
to Fort St. Joaquin on the Takutu. He left this place on September 20, 1838, 
sailing up the Takutu to its tributary, the Mahu, swinging from here northwestward 
to Roraima, thence southwestward to the Parima, up this river, and then, following 
the mountains, to Esmeralda on the Orinoco, along the Cassiquiare to the Rio 
Negro, down this river to the Rio Branco, and up this stream back to Fort San 
Joaquin on April 22d. He returned thence to Georgetown on June 20, 1839. 

The species he figured and noted, together with the identification of those 
dealt with in the present work, are given in the following list. Those from the 
northern slope are marked with an asterisk; those which have been found on the 
northern slope since Schomburgk's day are marked f. 



1. Acanthicus histrix Spix, p. 131, pi. 1. 
t 2. Loricaria cataphracta Linnaeus, p. 136. 
3. Hypostoma plecostomus Valenciennes, p. 
139. 
* 4. Hypostoma squalinum Schomburgk, p. 
142, pi. 2. 
5. Hypostoma punctatum Schomburgk, p. 



Vol. I. 

Rio Branco at Fort San Joaquin. 

Locality? = Loricaria cataphracta (Linnaeus). 

Rio Branco, 8 in. = Plecostomus plecostomus 

(Linnaeus). 
Rio Branco, Rio Negro, Essequibo. 13J4 in- = 

Plecostomus emarginatus (Cuv. & Val.). 
Rio Branco. 63^ in. 



150, 



145, figure. 
6. Hypostoma barbatus Cuv. & Val., p. 147. Loc ? Q}i in. = Pseudancistrus barbatus (Cuv. & 

Val.). 
Pools, marshes, and creeks. 8" in. = Hoploslernum 

thoracatum (Cuv. & Val.). 
Curassarraka on the Rupununi. 
12 in. = Doras costalus (Linnteus). 
Rio Negro. = Doras cataphractus (Linnaeus). 
Pasawiri. 7 in. =? Doras cataphractus (Linnaeus). 



* 7. Callichthys longifilis Cuv. & Val., p 

figure. 

* 8. Callichthys ? p. 152, figure, 
t 9. Doras costatus Lacepede, p. 155. 
flO. Doras cataphractus Linnaeus, p. 158. 

11. Doras caslaneo-ventris Schomburgk, p. 161, 

pi. 3. 
*12. Doras brunnescens Schomburgk, p. 163. 



13. Doras niger Valenciennes, p. 165. 

14. Doras, p. 166. 

6 In recent works this word is spelled Amacu. 



Upper Essequibo. 5 in. = ? Doras cataphractus 

(Linnaeus). 
Esmeralda. = Oxydoras niger (Val.). 
Orooporary on the Essequibo. 



18 MEMOIRS OF THE CARNEGIE MUSEUM 

*15. Phractocephalus hemilopterus Agassiz, All rivers of Guiana. 4 ft. = Phractocephalas 
p. 169, figure. hemiliopterus (Bloch & Schneider). 

16. Arius oncina Schomburgk, p. 173, pi. 4. Rio Padauiri. 10 in. = ? 

17. Arius obesus Schomburgk, p. 174. Rio Branco. 8 in. = ? 

*18. Pimelodus (Bagrus) maculatus Lacepede, Most of the rivers. 12 in. = Pimelodus clarias 

p. 175, figure. (Bloch). 

*19. ? ? ? p. 176. Demerara and Essequibo. 18-20 in. 

*20. Pimelodus arekaima Schomburgk, p. 178, Upper Essequibo and Rio Branco. 2 ft. 3 in. = 

pi. 5. Rhamdia arekaima (Schomburgk). 

f21. Pimelodus insignis Schomburgk, p. 180, Rio Branco. 18 in. = Pimelodella cristata (Miiller 

pi. 6. & Troschel). 

22. Pimelodus notatus Schomburgk, p. 181, Rio Branco. 3 feet. 

pi. 7. 

*23. Pimelodus pirinampu Spix, p. 183. Rivers of Guiana. 3 feet or more. = Piniram- 

pus pirinampu (Spix). 

24. Platystoma tigrinum Valenciennes, p. 185, Most rivers of Guiana. = Pseudoplatystoma fas- 

pi. 8. datum (Linnaeus). 

25. Platystoma planiceps Agassiz, p. 187. Rio Branco. 

26. Platystoma vaillanti Valenciennes,' p. 188. Guiana. To 2 ft. 3 in. = Brachy platystoma 

vaillanti Valenciennes. 

27. Hypophthalmus dawalla Schomburgk, p. Rivers of Guiana. 2J^ft. = Ageneiosusbrevifilis 

191, pi. 9. (Cuv. & Val.). 

*28. Lau-Lau, p. 193, figure. Rivers of Guiana. 10-12 ft. 200 lbs. = Platy- 

stoma vaillanti Valenciennes. 
*29. Sudis gigas Cuvier, p. 198, pi. 17. Rupununi, Rio Branco, Rio Negro. 15 ft. 410 

pounds = Arapaima gigas (Cuvier). 
*30. Osteoglossum aroivana Schomburgk, p. 205, Rupununi, Essequibo, Rio Branco, Rio Negro. 

pi. 10. = Osteogloss^l7n bicirrhosum Vandelli. 

31. Chalceus rotundatus Schomburgk, p. 209, Padauiri. 6-7 in = Chalcinusrotundatus (Schom- 

figure. burgk). 

*32. Chalceus tceniatus Schomburgk, p. 210. Essequibo, Rio Negro, Rio Branco. 15-18 in. 

= ? 
33. Chalceus labrosus Schomburgk, p. 212, pi. Rio Paduiri. 7 5J4 in. =? Brycon falcatus Miiller 

13. & Troschel. 

*34. Chalceus nigrotceniatus Schomburgk, p. Loc. ? 14-16 in. = Leporinus nigrotceniatus 
213, pi. 13. (Schomburgk). 

35. Chalceus latus Schomburgk, p. 214. Padauiri, tributary of the Rio Negro. 4 in. 

36. Chalceus fasciatus Schomburgk, p. 215. Padauiri. 18 in. 

*37. Chalceus macrolepidotus Cuvier, p. 216, pi. Essequibo. 15 in. = Chalceus macrolepidotus 

14. Cuvier. 

6 This species is given on the authority of Valenciennes. Its identity with the Lau-lau was not appre- 
ciated by Schomburgk. 

7 Padauiri? 



EIGKNMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



19 



f38. Anodus notatus Schomburgk, p. 218, pi. 15. 
f39. Serrasalmo piranha Spix, p. 221, pi. 16. 

*40. Serrasalmo stagnatilis Schomburgk, p. 222. 
?41. Serrasalmo punctatus Schomburgk, p. 223, 

pi. 17. 
?42. Serrasalmo ? p. 224. 
*43. Serrasalmo niger Schomburgk, p. 225, pi. 

18. 
?44. Salmo emarginatus Schomburgk, p. 231, 

pi. 19. 

45. Salmo undulatus Schomburgk, p. 232, 

figure. 

46. Serrasalmo scotopterus Schomburgk, p. 

233. 
*47. Myletes pacu Schomburgk, p. 236 pis. 20 

&21. 
47a, b, c. Morocoto* cartabac, palometo, pp. 239, 

240. 
*48. Tetragonopterus lotus Schomburgk, p. 241. 
49. Tetragonopterus schomburgkii Jardine, p. 

243, pi. 22. • 
*50. Xiphostoma ocellatum Schomburgk, p. 245, 

pi. 23. 



Rio Negro. = Anisitsia notatus (Schomburgk). 
Rio Branco. 10-11 in. = Pygocentrus piraya 

(Cuvier). 
Upper Essequibo, in pools. 8 in. = ? 
= Pygopristis denticulatus (Cuvier). 



All rivers of Guiana. 16 in. = Pygocentrus niger 

(Schomburgk). 
Loc. ? = Metynnis sp.? 

Padauiri. 6 in. = ? 

Rio Branco. 

Dikes of Essequibo. 24 in. = Myleus pacu 
(Schomburgk). 



All rivers of Guiana. = IMetynnis, sp.? 
Rio Negro. 



2 ft. 



Hy- 



Essequibo, Rios Negro and Branco. 
drocynus cuvieri (Agassiz). 

8 "The morocoto, cartabac, and a species of pacu which we found in the river Parama, and which differed 
only from the common pacu in its colour being black, constitute a group of fishes which resemble each other 
by structure, teeth, habits, and their being phytivorous. One of the most delicious among this division is the 
morocoto or osibu of the Warraus; it inhabits only the estuaries, and does not occur in fresh water; it would 
fall, therefore out of the limits of the present descriptions; but as it is so closely allied with the pacu, I shall 
mention at least its dimensions and general appearance. The teeth, which consist of fourteen in the upper jaw, 
and are placed in a double row in the fore part, are all distinctly molar or grinding teeth. It attains a length 
from about twenty-five to twenty-eight inches, and is twelve inches in depth. The gill covers consist of three 
strong bones, the dorsal fin of sixteen rays, the ventral of eight, and the anal of twenty-four, the caudal is 
compressed and thin; in every other respect it resembles the pacu, and is extremely fat and delicious. During 
the month of August, when they feed upon the fruit of the caramacata, a tree of large size and very hard wood, 
and the bark, leaves, and fruit of which is extremely bitter, their flesh has a bitter taste, but otherwise it is 
much sought after, and large numbers of it are occasionally brought from the mouth of the Orinoco to George- 
town. It forms the chief support of the Warrau Indians who inhabit the coast regions in the vicinity of the 
estuaries of the Orinoco and the months of the Guainia and Barima." 

"The palometo, which is about fourteen inches long and seven inches in depth, its body compressed 
and flat, with a thin sharp belly, is equally well flavoured as the morocoto and pacu, and frequents similar 
haunts as the morocoto." (Fishes of British Guiana, pp. 239-40.) I have not identified these species 
which are mentioned only by their Indian names. 



20 MEMOIRS OF THE CARNEGIE MUSEUM 

*51. Hydrocyon microlepis Schomburgk, p. 247, Essequibo, Rios Negro and Branco. = Acestro- 

pl. 24. rhynchus microlepis (Schomburgk). 

*52. Hydrocyon armatus Schomburgk, p. 249, All rivers of Guiana. 10-12 lbs. = Acesirorhyn- 

pl. 25. chus falcirostris (Cuvier). 

53. Schizodon fasciatus Spix, p. 252, pi. 26. Rio Branco. = Schizodon fasciatus Spix. 

*54. Erythrinus macrodon Schomburgk, non Berbice, beyond the cataract, Itabru, Cuyuni. 

Agassiz, p. 254, pi. 27. 4 ft. = Hoplias monophthalmus Pellegrin. 

*55. Huri, Cauhui, Tari-ira,* p. 256. In every river of Guiana. = Hoplias malabaricus 

(Bloch). 

*56. Prochilodus rubrotamiatus Schomburgk, p. Essequibo, Rios Branco and Negro. 2 lbs. - 

258, pi. 28. Prochilodus rubrotceniatus Schomburgk. 

57. Prochilodus binotatus Schomburgk, p. 260, Rio Branco. 13}^ in. 

pi. 29. 

58. Prochilodus insignis Schomburgk, p. 261, Rio Branco. llj^ in. 

pi. 30. 

Vol. II. 

59. Belone guianensis Schomburgk, p. 131, pi. Padauiri. 15 in. = Potamorhaphis guianensis 

1 . (Schomburgk) . 

*60. Sciccna rubella Schomburgk, p. 133. Most rivers. 2 feet. = Plagioscion squamosis- 

simus Heckel. 
*61. Corvina grunnicns Schomburgk, p. 136, Essequibo. = Pachypops grunniens (Schom- 

pl. 2. burgk). 

*62. Cychla labrina Agassiz, p. 139, pi. 3. Upper and lower courses. 6-7 inches. = Cre- 

nicichla saxatilis (Linnagus). 

63. Cychla fasciata Schomburgk, pi. 141, p. 4. Loc? = Crenicichla Johanna Heckel. 

64. Cychla rutilans Schomburgk, p. 142, pi. 5. Rio Branco. = Crenichla lugubris Heckel. 

65. Cychla fiavomaculata Schomburgk, p. Rio Negro and Padauiri. 2 ft. = Cichla ocellaris 

145, pi. 6. (Bloch & Schn.). 

66. Cychla nigro-macidata Schomburgk, p. 147, Rio Negro and Padauiri. 18 nches. = Cichla 

pi. 7. ocellaris (Bloch & Schn.). 

*67. Cychla argus Valenciennes, p. 149, pi. 8. Essequibo; Rio Branco; Rio Negro. = Cichla 

ocellaris (Bloch & Schn.). 

68. Cychla trijasciatus Schomburgk, p. 151, Rio Negro; Padauiri. = Cichla ocellaris (Bloch & 

pi. 9. Schn.). 

69. Cychla ? rubro-ocellatus Schomburgk, p. Rio Negro. = ? 

153, pi. 10. 

70. Centrarchus cychla Schomburgk, p. 157, Rio Negro. = ? 

pi. 11. 

71. Centrarchus niger Schomburgk, p. 159, pi. Rio Negro. 6%. = ? 

12. 

72. Centrarchus notatus Schomburgk, p. 160, Loc? = Cichlasoma severum (Heckel). 

pi. 13. 
9 This species is not listed under its scientific name. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 21 

73. Centrarchus f vittatus Schomburgk, p. 161, Loc? = ? 

pi. 14. 

74. Centrarchus ft rostralus Schomburgk, p. Rio Negro. 4.4 inches. = Acaropsis nassa 

163, pi. 15. (Heckel). 

*75. Centrarchus f cyanopterus Schomburgk, p. Essequibo. 3 in. = ? Cichlasoma bimaculatum 

165, pi. 16. (Linnaeus). 

76. Pomotis f fasciatus Schomburgk, p. 169, Rios Padauiri and Negro. 8.5 in. 

pi. 17. 

*77. Pomotis f bono Schomburgk, p. 171, pi. 18. All rivers, and in pools and marshes. 6.5 in. = 

Mquidens tetramerus (Heckel). 

78. Gymnotus eleclricus Linnaeus", p. 173, pi. Rio Negro. = Electrophorus electricus (Linnaeus). 

18. 

79. Gymnotus fasciatus Pallas, p. 174, pi. 19. Rio Branco. = Gymnotus carapo Linnaeus. 

80. Trigon histrix f D'Orbigny, p. 180, pi. 20. River Roowa. 12 inches. = Potamotrygon hys- 

trix (Muller & Henle). 

81. Trygon garrapa Schomburgk, p. 182, pi. Rio Branco. = Potamotrygon hystrix (Midler & 

21. Henle). 

82. Trygon strongylopterus Schomburgk, p. Rio Branco. = Paratrygon strongylopterus 

183, pi. 22. (Schomburgk). 

83. Elipesurus spinicauda Schomburgk, p. Rio Branco. 

184, pi. 23. 

84. Silurus parkeri Trail, p. 188, pi. 24. = Sciadeichthys parkeri (Trail). 

The brother, Richard Schomburgk, in the expeditions which have been men- 
tioned, ascended the Demerara River to near the "Great Fall," He also threaded 
the Pomeroon, Waini, and Barima Rivers, which discharge their waters west of 
the Essequibo. He ascended the Essequibo to' the Rupununi, following the latter 
to near its sources. From Pirara he ascended the Takutu to its source and de- 
scended it to Fort San Joaquin, whence he went to Roraima. His last collections, 
made on the trip to Roraima, were all lost. 

An account of his journeys was published in two volumes under the title 
"Reisen in British Guiana in den Jahren 1840-1844 im Auftrag Sr. Majestat des 
Konigs von Preussen." His collections were enumerated in a third volume. The 
new fishes were largely described in the "Horse Ichthyologicse," by Miiller & 
Troschel, who also prepared the account of the fishes in this third volume. He gives 
many notes on the habits of the fishes in the first two volumes. Mtiller & Troschel 
enumerate one hundred and forty-one species as represented in his collections. 10 
Most of these I had an opportunity of examining in the Zoological Museum in 

10 To these Schomburgk adds ten species known to him, but not recognized by Miiller and Troschel. 
Some of these, like Myletes pacu, as Schomburgk himself noted, were given by Miiller & Troschel under other 
names. 



22 MEMOIRS OF THE CARNEGIE MUSEUM 

Berlin during July of 1910. On account of lack of time no effort was made to 

verify the marine or estuarine species. The list of species with the identification 
of those dealt with in the present volume is given in the following table. 

1. Centropomus undecimalis Cuvier & Val- Coast. 1-2 ft. = Centropomus undecimalis 

enciennes, p. 620. (Bloch). 

2. Serranus galeus Muller & Troschel, p. 621. Coast. 

3. Pomotis calesbei Cuvier & Valenciennes, 

p. 621. 

4. Otolithus toe-toe Cuvier & Valenciennes, Coast. 8-10 in. = Cynoscion acoupa (Lac6- 

p. 621. pede). 

5. Otolithus leiarchus Cuvier & Valenciennes, Coast. 12-14 in. 

p. 621. 

6. Ancylodon jaculidens Cuvier & Valen- Coast. 6-8 in. = Macrodon ancylodon (Bloch & 

ciennes, p. 621. Schneider). 

7. Micropogon lineatus Cuvier & Valen- Coast. 1-2 ft. = Micropogon furnieri (Desrnar- 

ciennes, p. 621. est). 

8. Micropogon trifilis Muller & Troschel, p. Coast. 16-18 in. = Pachypops furcrwus Lace- 

622. pede. 

9. Polycentrus schomburgkii Muller & Tros- Essequibo. = Polycentrus schomburgkii Eigen- 

chel, p. 622. mann. 

10. Gerres rhombeus Cuvier & Valenciennes, p. Coast. 10-12 in. 

622. 

11. Acharnes speciosus Muller & Troschel, p. Mouth of Essequibo. 6-8 in. = Cichla ocellaris 

622. Bloch & Schneider. 

12. Chorinemus salie?is Cuvier & Valen- Coast. 2-6 ft. 

ciennes, p. 623. 

13. Caranz carangus Cuvier & Valenciennes, Coast. 2-6 ft. 

p. 623. 

14. Mugil liza Cuvier & Valenciennes, p. 623. Mouths of rivers. 18-20 in. 

15. Mugil curema Cuvier & Valenciennes, p. Mouths of rivers. 16-18 in. 

623. 

16. Gobius bacalaus Cuvier & Valenciennes, p. Coast. 

623. 

17. Eleotris guavina Cuvier & Valenciennes, p. Mouths of rivers. 8-10 in. = Guavina guavina 

623. (Cuvier & Valenciennes). 

18. Batrachus surinamensis Bloch & Schnei- Coast. 8-10 in. 

der, p. 623. 

19. Monochir maculipinnis Agassiz, p. 624. Coast. 20-26 in. 

20. Acara margarita Heckel, p. 624. Amucu Swamps. 8-10 in. = Cichlasoma bi- 

maculaia (Linnaeus). 

21. Acara nassa Heckel, p. 624. Lake Tapacuma. 4-6 in. = Acaropsis nassa 

Heckel. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 23 

22. Acara tetramerus Heckel, p. 624. Lakes Tapacuma, Capoye, and Amucu. 4-6 in. 

= Mquidens tetramerus (Heckel). 

23. Acara heckelii Miiller & Troschel, p. 624. Swamps and savannahs. 4-6 in. = Acarichthys 

heckelii (Miiller & Troschel). 

24. Chcetobranchus flavescens Heckel, p. 625. Amucu. 6-8 in. = Cha>tobranchus flavescens 

Heckel. 

25. Geophagus jurupari Heckel, p. 625. Amucu, swamps and savannahs. 8-10 in. = 

Geophagus jurupari Heckel. 

26. Geophagus surinamensis Miiller & Tros- Lakes Tapacuma, Capoye, and Amucu. 4-6 in. 

chel, p. 625. = Geophagus surinamensis Miiller & Troschel. 

27. Geophagus leucostictus Miiller & Troschel, Amucu. 4-6 in. = Geophagus jurupari Heckel. 

p. 625. 

28. Geophagus pappaterra Heckel, p. 625. Amucu (Tributary of Branco). 4 in. = Geophagus 

jurupari Heckel. 

29. Cichla ocellaris Bloch & Schneider, p. 625. All rivers. 2J^ ft. = Cichla ocellaris Bloch & 

Schneider. 

30. Crenicichla saxatilis Heckel, p. 626. All rivers. = Crenicichla sazatilis Heckel. 

31. Crenicichla vittata Heckel, p. 626. Essequibo, Lakes Tapacuma and Capoye. = Cren- 

icichla lugubris Heckel. 

32. Crenicichla lugubris Heckel, p. 626. Essequibo and neighboring swamps. = Crenicichla 

lugubris Heckel. 

33. Tylosurus guianensis Miiller & Troschel, Coast. 1-2 ft. = Tylosurus almeida Quoy & 

p. 626. Gaimard. 

34. Bagrus mesops Cuvier & Valenciennes, p. Waini and Barima. 2 ft. = Selenaspis herz- 

627. bergii (Bloch). 

35. Bagrus proops Valenciennes, p. 627. Waini and Barima. 18-20 in. = Sciadeichthys 

proops (Cuvier & Valenciennes). 

36. Bagrus passany Valenciennes, p. 627. = Selenaspis passany (Cuvier & Valenciennes). 

37. Bagrus clarias Miiller & Troschel, p. 627. Waini & Barima. 12-14 in. = Pimelodus clarias 

(Bloch). 

38. Bagrus coelestinus Miiller & Troschel, 627. Waini & Barima. = Selenaspis herzbergii (Bloch). 

39. Bagrus emphysetus Miiller & Troschel, p. Waini and Barima. = Sciadeichthys emphysetus 

627. (Miiller & Troschel). 

40. Platystoma tigrinum Valenciennes, p. 627. Nearly all rivers. 2Yi ft. = Pseudoplaty stoma 

fasciatum (Linnseus). 

41. Platystoma platyrhynchus Valenciennes, p. Rupununi. = Hemisorubim platyrhyncos Cuvier 

628. & Valenciennes. 

42. Galeichthys gronovii Valenciennes, p. 628. Waini and Barima. = Felichthys bagre (Linnseus) . 

43. Pimelodus sebce Valenciennes, p. 628. All rivers. 8-10 in. = Rhamdia sebce (Cuvier & 

Valenciennes). 

44. Pimelodus raninus Valenciennes, p. 628. All rivers. 6-8 in. = Pseudopimelodus villosus 

Eigenmann. 



24 MEMOIRS OF THE CARNEGIE MUSEUM 

45. Pimelodus cristatus Muller & Troschel, p. Takutu and Mahu. 16-18 in. = Piinodella cris- 

628. lata (Muller & Troschel). 

46. Pimelodus foina Muller & Troschel, p. 628. Takutu. 7-8 in. = Rhamdella foina (Muller & 

Troschel. 

47. Pimelodus eques Miiller & Troschel, p. 628. All rivers. 16-18 in. = Goeldiella eques (Muller 

& Troschel). 

48. Pimelodus stegelichii Muller & Troschel, p. Forest brooks. 10-12 in. = Rhamdia sebce Cu- 

628. vier & Valenciennes). 

49. Calophysus macropterus Muller & Tros- Essequibo. 12 in. = Callophysus macropterus 

chel, p. 629. (Lichtenstein). 

50. Auchenipterus maculosus Valenciennes, p. Essequibo. 4-6 in. = Trachycorystes galealus 

629. (Linnaeus). 

51. Auchenipterus furcatus Valenciennes, p. Essequibo. 6-8 in. = Pseudauchenipterus nodo- 

692. sms (Bloch). 

52. Doras armatulus Valenciennes, p. 629. Rupununi and Awaricuru. 10 in. = Doras costa- 

tus (Linnseus). 

53. Doras niger Valenciennes, p. 629. All rivers. 10-12 in. = Oxydoras niger (Valen- 

ciennes). 

54. Doras carinatus Valenciennes, p. 629. Essequibo. 10-12 in. = Hemidoras carinatus 

(Linnaeus). 

55. Doras maculatus Valenciennes, p. 629. Essequibo. 2 ft. = Doras grayiulosus (Valen- 

ciennes). 

56. Callichthys coelatus Cuvier & Valenciennes, Trenches. 4-6 in. = Callichthys callichthys 

p. 630. (Linnaeus). 

57. Callichthys exaratus Muller & Troschel, Trenches. 4-6 in. = Hoplosternum thoracatum 

p. 630. (Cuvier & Valenciennes). 

58. Callichthys pictus Muller & Troschel, p. Trenches. 4-6 in. = Hoplosternum thoracatum 

630. (Cuvier & Valenciennes). 

59. Aspredo lozvis Valenciennes, p. 630. Waini. = Aspredo aspredo (Linnaeus). 

60. Aspredo tibicen Temminck, p. 630. Coast. 10-12 in. = Aspredinichthys tibicen 

(Temminck). 

61. Acanthicus hystrix Spix, p. 630. Takutu and Rio Branco. 3-3^ ft. = Acanthicus 

hystrix Spix. 

62. Loricaria cataphracta Linnaeus, p. 631. Rupununi. 8-10 in. = Loricaria cataphracta 

Linnaeus. 

63. Loricaria acuta Valenciennes, p. 631. Rupununi. 8-10 in. = Loricariichthys microdon 

Eigenmann. 

64. Loricaria platyura Muller & Troschel, 631. Rupununi. 8 in. = Loricariichthys platyura 

(Muller & Troschel). 

65. Hypostomus commersonii Valenciennes, p. Takutu. 6-8 in. = Plecostomus verres (Cuvier 

631. & Valenciennes). 

66. Hypostomus itacua Valenciennes, p. 631. Takutu. 3—4. = Hemiancistrus braueri Eigen- 

mann. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 25 

67. Hypostomus temminckii Valenciennes, p. Takutu. 2-3 in. = Ancistrus temminckii Cuvier 

631. & Valenciennes. 

68. Hypostomus nudiceps Miiller & Troschel, Takutu. 2-3 in. = Xenocara gymnorhynchus 

p. 631. (Kner). 

69. Anableps letrophthalmus Bloch, p. 632. Mouths of streams. 6-8 in. = Anableps ana- 

bleps (Linna?us). 

70. Anableps microlepis Miiller & Troschel, Mouths of streams. 4-6 in. = Anableps micro- 

p. 632. lepis Miiller & Troschel. 

71. Pcecilia vivipara Bloch & Schneider, p. 632. Georgetown canals and others. J-^ in. = 

Poecilia vivipara Bloch & Schneider. 

72. Erythrinus unitamiaius Spix, p. 632. Swamps, streams, and brooks of the Canuku Mts. 

8-10 in. = Hoplerythrinus unitceniatus (Spix). 

73. Erythrinus salmis Agassiz, 632. Small forest streams and standing water. 10-14 

in. = Hoplerythrinus unitceniatus (Spix). 

74. Macrodon trahira Miiller, p. 632. Generally distributed in British Guiana. = Hop- 

lias macrophthalmus Pellegrin. 

75. Macrodon brasiliensis Miiller, p. 633. Generally distributed, British Guiana. 12-14 in. 

= Hoplias malabaricus (Bloch). 

76. Anodus alburnus Miiller & Troschel, p. Lake Amucu and swamps of the savannah. Up to 

633. 10 in. = Curimatella alburna (Miiller & Tros- 
chel). 

77. Anodus ciliatus Miiller & Troschel, p. 633. Lake Amucu. 6-8 in. Curimatus ciliatus (Miiller 

& Troschel). 

78. Pacu nigricans Spix, p. 633. Generally distributed, British Guiana. 6-8 in. 

= fPygocentrus piraya (Cuvier). 

79. Hemiodus unimaculatus Miiller & Troschel Essequibo. 6-8 in. = Anisitsia notata Schom- 

p. 633. burgk". 

80. Piabuca argentina Cuvier, p. 633. Lake Amucu and swamps of the savannah. 3^4 

in. = Piabucus dentatus Kcelreuter. 

81. Chilodus punctatus Miiller & Troschel, 634. Still water of the savannah. 3-4 in. = Chilodus 

punctatus Miiller & Troschel. 

82. Schizodon fasciatus Agassiz, p. 634. Upper Rupununi, Rio Branco, Takutu, and the 

swamps near these. = Chilodus punctatus 
Miiller & Troschel. 

83. Leporinus fasciatus Miiller & Troschel, p. Pirara and nearby swamps. = Leporinus fasci- 

634. atus Bloch. 

84. Leporinus nigrotozniatus Miiller & Tros- Abundant in upper Pomeroon and its tributary 

chel, p. 634. forest brooks. 4-6 inches. = Leporinus nigro- 

taniatus (Schomburgk) . 

85. Leporinus maculatus Miiller & Troschel, p. Abundant in Rupununi and Awaricuru. 6-8 in. 

634. = Leporinus maculatus Miiller & Troschel. 

86. Leporinus frederici Agassiz, p. 634. Pomeroon. 12-14 in. = Leporinus friderici 

Bloch. Bloch. 



26 MEMOIRS OF THE CARNEGIE MUSEUM 

87. Tetragonopterus argenteus Artedi, p. 634. Lake Amucu. 4-6 in. = Tetragonopterus argen- 

teus Artedi. 

88. Tetragonopterus maculatus Miiller & Tros- Rupununi and Essequibo and the swamps and 

chel, p. 634. morasses near by. 3-4 in. = Pcecilurichthys 

bimaadatus (Linnaeus). 

89. Tetragonopterus melanurus Miiller & Tros- Upper Rupununi. 4-6 in. = Creatochanes caud- 

chel, p. 635. omacidatus Giinther. 

90. Tetragonopterus tmiiatus Jenyns, p. 635. Trenches and swamps along the coast. 1-2 in. 

= Moenkhausia oligolepis (Giinther). 

91. Chalceus angulatus Spix, p. 635. Essequibo and Rupununi. 6-8 in. = Chalceus 

rotundatus (Schomburgk). 

92. Brycon macrolepidotus Miiller & Troschel, Lower Essequibo and Mazaruni. 6-8 in. = 

p. 635. Chalceus macrolepidotus Cuvier. 

93. Brycon falcatus Miiller & Troschel, p. 635. Generally distributed, British Guiana. 6-8 in. 

= Brycon falcatus Miiller & Troschel. 

94. Brycon schomburgkii Miiller & Troschel, Plentiful in lower Essequibo. 6-7 in. = Brycon 

p. 635. falcatus Miiller & Troschel. 

95. Brycon pesu Miiller & Troschel, p. 635. Lower Essequibo and Mazaruni. 4-6 in. = 

Holobrycon pesu (Miiller & Troschel). 

96. Exodon paradoxus Troschel, p. 635. Plentiful in creeks of the upper Rupununi. 4-6 in. 

= Exodon paradoxus Troschel. 

97. Epicyrtus gibbosus Miiller & Troschel, p. Plantation drains and lower Essequibo. 4-6 in. 

= Charax gibbosus (Linnseus). 

98. Xiphoramphus falcatus Miiller & Troschel, Essequibo and Pomeroon. 6-8 in. = Acestro- 

p. 635. rhynchus falcatus (Bloch). 

99. Xiphoramphus microlepis Miiller & Tros- Pomeroon, upper Essequibo, Rupununi, and 

chel, p. 636. Takutu. = Acestrorhynchus microlepis (Miiller 

& Troschel). 

100. Hydrolycus scomberoides Miiller & Tros- Generally distributed. 2-3 ft. = Hydrolycus 

chel, p. 636. scomberoides (Cuvier). 

101. Agoniates halecinus Miiller & Troschel, p. Cuyuni. 6 in. = Agoniates halecinus Miiller & 

636. Troschel. 

102. Xiphostoma cuvieri Spix, p. 636. Upper Essequibo, Rupununi, and Takutu. 2 ft. 

= Hydrocynus cuvieri (Agassiz). 

103. Pygocentrus piraya Miiller & Troschel, p. Generally distributed in British Guiana. 10-12 in. 

636. = Pygocentrus piraya (Cuvier). 

104. Pygocentrus nigricans Miiller & Troschel, Generally distributed. 11-12 in. = Pygocentrus 

p. 636. piraya (Cuvier). 

105. Pygocentrus niger Miiller & Troschel, p. Generally distributed, British Guiana. 16-20 in. 

636. = Pygocentrus niger (Schomburgk). 

106. Pygopristis denticulatus Miiller & Troschel, Essequibo, Rupununi, Takutu, and near-by 

p. 637. swamps. = Pygopristis dentiadatus (Cuvier). 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



27 



107. Pygopristis fumarius Miiller & Troschel, 

p. 637. 

108. Serrasalmo rhombeus Miiller & Troschel, p. 

637. 

109. Serrasal?7io aureus Spix, p. 637. 

110. Catoprion mento Miiller & Troschel, p. 

637. 

111. Myletes rubripinnis Miiller & Troschel, p. 

637. 

112. Myletes schomburgkii Miiller & Troschel, 

p. 637. 

113. Myletes hypsauchen Miiller & Troschel, p. 

637. 

114. Myletes latus Miiller & Troschel, p. 638. 

115. Myletes asterias Miiller & Troschel, p. 638. 

116. Myleus setiger Miiller & Troschel, p. 638. 

117. Osteoglossum bicirrhosum Spix, p. 638. 



118. Arapaima gigas Miiller, p. 638. 

119. Megalops atlanticus Valenciennes, p. 639. 

120. Elops saurus Linnaeus, p. 639. 

121. Engraulis thrissoides Miiller & Troschel, p. 

639. 

122. Gymnothorax ocellatus Agassiz, p. 638. 

123. Gymnotus eleclricus Linnaeus, p. 639. 

124. Sternopygus virescens Miiller & Troschel, 

p. 639. 

125. Sternopygus lineatus Miiller & Troschel, p. 

640. 

126. Rhamphichthys rostratus Miiller & Troschel, 

p. 640. 



Rupununi, Essequibo, and near-by swamps. 4-6 
in. Pygopristis denticulatus (Cuvier). 

Rupununi, Takutu, and near-by swamps. 12-14 
in. = Serrasalmo rhombeus (Linnaeus). 

Essequibo and Rupununi. 6-8 in. = ? Serrasal- 
mo gymnogenys Giinther. 

Lake Amucu. 3-4 in. = Catoprion mento 
(Cuvier). 

Lower Essequibo. 4-6 in. = Myloplus rubri- 
pinnis (M. & T.). 

Rupununi, Takutu, Zuruma, as well as swamps of 
the savannah. 4-6 in. = Myleus pacu (Schom- 
burgk) . 

Standing water, Tapacuma Lake. 3^ in. = 
Metynnis hypsauchen (Miiller & Troschel). 

Generally distributed in British Guiana. 10-12 in. 
= Myloplus rhomboidalis (Cuvier). 

Essequibo and Mazaruni near falls. 2 ft. = 
Myloplus asterias (Miiller & Troschel). 

Essequibo near cataracts and in swift water. 10- 
12 in. = Myleus pacu (Schomburgk). 

Still water of Rupununi, Takutu, Rio Branco and 
near-by swamps of savannah, and in Lake Amu- 
cu. J/2 ft. = Osteoglossum bicirrhosum Van- 
delli. 

Generally distributed in streams of British Guiana. 
8-10 ft. = Arapaima gigas Cuvier. 

Along the coast. 2 ft. = Tarpon atlanticus 
(Cuvier & Valenciennes). 

Along the coast. 12-14 in. 

Cuyuni. 4-7 in. = Stolephorus sjrinifer (Cuvier 
& Valenciennes). 

Plantation drains and standing water. 3-4 ft. 
= Lycodontis ocellatus (Agassiz). 

All fresh water of British Guiana. 7 ft. = Elec- 
trophorus electricus (Linnaeus). 

Lake Amucu and forest streams. 18-20 in. = 
Eigenmannia virescens (Valenciennes). 

Small forest brooks. 6-10 in. = Eigenmannia 
virescens (Valenciennes). 

Demerara River. 4-6 ft. = Rhamphichthys ros- 
tratus (Linnaeus). 



28 



MEMOIRS OF THE CARNEGIE MUSEUM 



127. Sternarchus oxyrhynchus Miiller & Tros- 

chel, p. 640. 

128. Synbranchus marmoratus Bloch, p. 640. 

129. Chelichthys punctatus Miiller & Troschel, p. 

641. 

130. Chelichthys psittacus Miiller & Troschel, p. 

641. 

131. Chelichthiji asellus Miiller & Troschel, p. 

641. 

132. Syngnathus pelagicus Linnaeus, p. 641. 

133. Carcharias (Prionodon) henlei Valencien- 

nes, p. 641. 

134. Carcharias (Prionodon) oxyrhynchus Miil- 

ler & Henle, p. 642. 

135. Sphyrna tudes Miiller & Henle, p. 642. 

136. Pristis pectinatus Latham, p. 642. 

137. Tamiura motoro Miiller & Henle, p. 642. 

138. Trygon garapa Schomburgk, p. 642. 

139. Trygon strongyloplerus Schomburgk, p. 642, 

140 Hypostomus plecostomus Valenciennes, p. 
643. 

141. Hypostoynus squalitus Schomburgk, p. 642. 

142. Phractocephalus hemiliopterus Agassiz, p. 

643. 

143. Pimelodus arekaima Schomburgk, p. 643. 

144. Pimelodus insignis Jardine, p. 643. 

145. Hypophthalmus dawalla Schomburgk, p. 

643. 

146. Myletes pacu Schomburgk, p. 644. 

147. Prochilodus rubro-tceniatus Schomburgk, 

p. 644. 

148. Trygon histrix Schomburgk, p. 644. 



Lower Essequibo. 16-18 in. = Sternarchorhyn- 
chus oxyrhynchus Miiller & Troschel. 

Drains of the plantations. 2-3 ft. = Synbran- 
chus marmoratus Bloch. 

Sand banks of the coast. 12-15 in. 

Mouths of the Waini and Barima and sand-banks 
of the coast. 4-6 in. = Colomesus psittacus 
(Bloch & Schneider). 

Fresh water, Barima. 4 in. = Colomesus psit- 
tacus (Bloch & Schneider). 

Salt water near the coast. 10-12 in. 

Found on whole coast, especially near the mouth 
of the Demerara. 4-6 ft. 

Coast, especially near the mouth of the Demerara. 
6-8 ft. 

Whole coast, especially mouth of Demerara. 4-6 
ft. 

Coast. 4-6 ft. 

Mouth of the Zuruma. 6-8 in. = Potamotrygon 
hystrix (Miiller & Troschel). 

Takutu and Rio Branco. 8-10 in. = Potamotry- 
gon hystrix (Miiller & Troschel). 
Rupununi, Takutu, and Rio Branco. 8-10 in 
= Paratrygon orbicularis Bloch & Schneider. 

Takutu and Rio Branco. 8 in. = Plecostomus. 
plecostomus (Linnaeus). 

Essequibo, Rio Branco, and Takutu. = Plecos- 
tomus emarginatus Cuvier & Valenciennes. 

Generally distributed in British Guiana. 2 ft. 11 
in. to 4 ft. 2 in. = Phractocephalus hemiliop- 
terus Agassiz. 

All rivers of the savannah. 2-3 ft. = Rhamdia 
arekaima Schomburgk. 

Takutu and Rio Branco. = Pimelodella cristata 
(Miiller & Troschel). 

Rivers of British Guiana. 2-3 ft. = Ageneiosus 
brevifilis Cuvier & Valenciennes. 

= Myletes pacu Schomburgk. 

Essequibo and tributaries. 18-20 in. = Pro- 
chilodus rubrotomiatus Schomburgk. 

Rupununi, Takatu, and Rewa. = Potamotrygon 
hystrix (Miiller & Troschel). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 29 

The Lau-lau is mentioned without referring it to any other name. 

One other collection of note was made in British Guiana by a Mr. A Ehrhardt. 
He collected at Mocco Mocco and Arisaro, spending about two months on the Esse- 
quibo. Part of his collection is in the British Museum, part in the Berlin Museum. 
The portion in the British Museum was reported upon by Giinther in his " Catalogue 
of Fishes in the British Museum," and in a short paper " On New Species of Fishes 
from the Essequibo," published in the Annals & Magazine of Natural History, 
December, 1863. 

The new things described are: Acara punctulata = Crenicara punctulata 
(Giinther) ; Pimelodus holomelas = Rhamdia holomelas (Giinther) ; Auchenipterus 
obscurus = Trachycorystes obscurus (Giinther); Helogenes marmoratus Giinther; 
Crenuchus spilurus Giinther; Leporinus megalepis Giinther = Leporinus maculatus 
Mutter & Troschel, and Xiphoramphus ferox Giinther = Acestrorhynchus falcatus 
(Bloch). 

As I have already stated in the introduction, in none of these papers was a 
definite locality given. 

In recent years Mr. T. Sidney Hargreaves collected fresh-water fishes in 
British Guiana. They were deposited in the Georgetown Museum. Few have 
definite locality labels. Mr. Hargreaves published a series of articles in "The 
Argosy," a local paper, which were reprinted in book form. The booklet is only 
of local interest, and adds but little which is of a sufficiently specific nature to be 
quoted in a scientific work. 



CHAPTER III. 



GENERAL ACCOUNT OF THE EXPEDITION. 

Accompanied by Mr. S. E. Shideler, I sailed from New York on August 23, 
1908, arriving in Georgetown on September 6th. 

From August to December is the long dry season in Guiana. In consequence 
the upper portions of the rivers are lowest in October and November, and the 
fishes are then concentrated in the channels of the streams. We had rain during 
the first week of our stay in Guiana, but later were only once interrupted by rain 
or high water. While on the Guiana plateau at Holmia a rain lasting a day and 
a night caused the river to rise many feet. 



' 



mmmi 




Fig. 1. Mouth of the Demerara River at Georgetown, British Guiana. 

The two main objects of the expedition have been outlined in the Introduction. 

I desired to secure as many characins as possible and to compare the fauna of the 

plateau with that of the lowland. The former became an incident in the study of 

the latter question. To get an idea of the lowland fauna a series of collections. in 

fresh water was made at sea-level within tidal influence from Lama Stop-Off to 

Morrawhanna, Wismar, Malali, and Bartica. Above tidal influence collections 

were made at Rockstone, Crab Falls, Ivonawaruk, and Warraputa, in the Essequibo 

and along the Potaro from its mouth to the Kaieteur. The fauna of the plateau 

was studied in the Potaro from the Kaieteur to the Aruataima Cataract. 

30 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



31 



Our equipment consisted of two barrels of alcohol, ten gallons of formalin, a 
Baird collecting-net, having a quarter of an inch mesh, fifteen feet long and five 
feet deep, a similar net forty-five feet long and seven feet deep, a net one hundred 
and fifty feet long with one-inch mesh in the wings and half-inch mesh in the other 
seventy-five feet, several gross of vials, several glass stoppered bottles, numerous 
empty one-pound coffee-tins, several five-gallon galvanized iron cans with screw- 
tops, one large galvanized iron can, buckets, etc. Kerosene tins were used in 
shipping specimens home. 

Immediately upon my arrival I rented a house of two rooms named "Charity," 
which stood between two others called "Faith" and "Hope." The preliminaries 
of attending to the customs, moving in, making several trips to the bank and the 
office of the Consul before my draft was accepted, making calls, and securing 
transportation, consumed Monday and Tuesday, September 7th and 8th. On 
Wednesday at 5 A.M. I visited the market, and from that time forward until 




Fig. 2. A trench in Georgetown. 



my return from the Kaieteur every calory of energy was consumed for the one 
object of making the trip successful. 

Georgetown is but a few inches above high tide; parts of it, in fact, are below 
tide. Many of the streets are provided with a wide central trench for drainage. 
Some of these are provided with tide-locks. One canal brings water from the 
Lamaha Conservancy, concerning which a little more later. The trenches are 



32 



MEMOIRS OF THE CARNEGIE MUSEUM 



planted with various native and exotic water-plants, one with Victoria regia, one 
with lotus, and so forth. The Lamaha trench is abundantly supplied with in- 
digenous water-plants. 

We began seining in the trenches of Georgetown as soon as our baggage was 
cleared and other preliminaries were attended to, and devoted four days to them. 
Toward the end of our stay in the country Mr. Shideler devoted himself again to 
the trenches, and particularly to those of the Botanic Garden, one of which he 
drained of its water, the results being given in a list published in a later chapter. 

We took altogether thirty-nine species (to which Mr. Ellis has added another) 
from the trenches, four of which we found nowhere else in Guiana: Plecostomus 
watwata, the sea-hassar, Ctenobrycon spilurus, Pcecilia vivipara, and Acanthophacelus 
melanzonus. 

The first is found from Georgetown along the coast to Para. The second has 
been taken only in Georgetown and Surinam. A close relative is exceedingly 




Fig. 3. View of the lowlands looking seaward from the railway near Mahaica. 



abundant in the Amazons. The third is widely distributed in the West Indies and 
South America, while the last has not been taken elsewhere. The water in most 
of the trenches in which we collected is fresh; that in a muddy pond at the lower 
end of the town may be at times contaminated with brackish water. Few of the 
species characteristic of brackish water were taken in the trenches. There were no 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



33 



marine cat-fishes or Banjamans, both groups excessively abundant in the brackish 
water. 

The species most abundant were Pristella riddled, a highly colored little characin 
first reported from the Orinoco and also found at Wismar; Hemigrammus rodwayi, 
another little characin confined to Georgetown and the northwest coast; the widely 
distributed characins Pcecilurichthys bimaculatus and Charax gibbosus, the latter of 
which was most abundant of all; the eels, Sternopygus macrurus, Eigenmannia 
virescens, the poecilid " Millions " and the cichlid Cichlasoma bimaculatum. 



«i 




yank* fflfc. , 


w^^ SH 


^I^Hi^^iiH 






' 



Fig. 4. View of the drainage canal at Cane-Grove Corner. 

The fauna of the trenches as a whole is poor as compared with that of the 
interior. This character the trenches share with the streams of the northwestern 
territory near the coast, and the waters about Lama Stop-Off . Many of the species 
are so small that our nets having one-quarter inch mesh permitted them to get 
through without difficulty. This may in part account for the apparent restriction 
of some of the species in the different trenches. Of Pristella riddlei we took with 
our nets but eight specimens in the Georgetown trenches, while in the trench of 
the Botanic Garden, which was drained, we obtained two hundred and thirty-three. 

Having packed the specimens from Georgetown we left on the 15th for Lama 



34 MEMOIRS OF THE CARNEGIE MUSEUM 

Stop-Off. It may be reached either by boat directly through the canal, or by rail and 
boat by way of Mahaica. Arrangements were made for us to go via Mahaica. 
The railroad runs through a flat country grazed by cattle, often standing up to their 
knees, or even deeper, in water. In places cocoanut-plantations abound and at 
frequent intervals canals run across the country to the ocean. Burnt clay is used 
in ballasting the railroads and in building the roads. Between the station at 
Mahaica and Cane-Grove Corner are a number of sugar-estates, all traversed 
by canals. 11 At Cane-Grove Corner the Lama Water Conservancy begins. It is a 
large tract of swampy savannah converted into a pseudo-lake, or water reservoir, 
by surrounding it with a ditch or canal and an outer embankment. At Lama 
Stop-Off and Maduni Stop-Off two streams, the Lama and the Maduni, tributaries 
of Mahaica Creek, formerly draining the savannah, are " stopped off " or dammed. 

11 The following from Rodway gives a picture of a single plantation: 

" One of the principal estates situated on the east coast of Demerara is two hundred roods on facade 
by the full depth of two thousand two hundred and fifty roods, i. e., about half a mile wide by five and a half 
deep. In front is the seashore, to protect which mangrove and courida bushes are allowed to grow, inside of 
which a dam of earth is thrown up, the excavation alongside forming a drain for carrying off any salt water 
that may come over during high tides. At a short distance within the front dam comes the public road, which 
extends along the coast, and which is kept up at the expense of the estate owner, as far as it extends through his 
property. Beyond the road, which with its two canals at the sides forms a second dam, comes about a mile 
of grassy land which is used for pasturing cattle, horses, and mules belonging to the plantation. Then comes 
the railway, near which is the draining engine and kokers or sluices of the canefields, which commence immedi- 
ately behind this third defence. Beyond a mile or so of pale green sugar-cane come the plantation buildings, 
which consist of the sugar factory, manager's residence, house for the overseers, hospital, school-house, one or 
two shops, and the labourers' cottages, which last are very numerous. This group of buildings forms, to all 
intents and purposes, a self-contained village, the manager's house, standing in the midst of a fine garden, 
representing the mansion of the squire, while round liim live as many mechanics and labourers as are necessary 
to carry on the cultivation and factory. Beyond this village come interminable fields of canes as far as the 
cultivation extends, where a back dam protects it from floods. The plantation under review had some years 
ago nine hundred and thirty-five acres, or exactly half its area, planted with canes, and produced over fifteen 
hundred hogsheads of sugar annually. The remaining portion comprised three hundred and fifty-eight acres 
in pasture and bush, one hundred and sixty-two acres not then empoldered, one hundred and ninety-eight acres 
in dams, parapets, and trenches, one hundred and sixty-two acres of swamp in front, above low water mark, 
but outside the sea dam, and fifty-three acres covered by the buildings, garden, public road, railway, etc. 
From the number of acres in dams and trenches it may be seen how important this part of the economy of 
the plantation must be. On every hand is an earthen dam with corresponding canals, these latter being cut off 
from outside by flood-gates, so that no water from sea or swamp can penetrate, while the rainfall of the plan- 
tation itself is run off through the sluices at low water, or in very heavy weather, by means of the draining 
engine. These draining canals are connected with other trenches between every field, and these again with the 
ditches of each bed of canes. With such a perfect system of canals it has naturally followed that sugar canes 
are brought to the factory by water, and to complete the communication a middle dam and two canals are car- 
ried through the center of the plantation to the factory and thence up to the railway, or to the shipping-trench, 
where the droghers take the produce to the port by sea." 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



35 



We embarked on the canal a Cane-Grove Corner and went about nine miles to 
Lama Stop-Off, where we made our headquarters, as the guests of Mr. St. Aubyne 
from the 15th to the 19th of September. Lama Stop-Off, according to a map at 
hand, is about twenty-two miles from Georgetown in a straight line. Lama Creek 
below the dam is influenced by the tide so that the top of the dam is but a few feet 
above Georgetown. 

Fishes are exceedingly abundant at Lama Stop-Off, although the number of 
species does not seem to be large. Undoubtedly several more species might have 
been secured if we could have used dynamite or poison. We arrived at nine in the 
evening and fishes could be heard jumping out of the water in all directions. We 
were awakened in the morning by the howling of monkeys. The entire force at 
the command of Mr. St. Aubyne was put to work to use every device known to 
him, or brought by us, to gather everything there was in the water. 

A naked negro baby caught the enthusiasm, walked into the edge of the water 
with a market basket, and made a dip, catching a specimen of Carnegiella! It 




Fig. 5. Photograph of Carnegiella strigata in aquarium. 



was the first time the fish had been caught since it was described by Gunther from 
his poor material without a known locality. Naturally I was very anxious to 
catch more. In spite of all our efforts we did not catch a second specimen at this 
place. We found it later at Maduni Stop-Off and in other places. Cichlids were 
very abundant here, and the delicious luckananee (Cichla) was more abundant 
here than we found it elsewhere. It gave me particular pleasure, in honor of Mr. 
St. Aubyne, to apply the name Pristella aubynei to the species from this place, 
of which we collected more specimens han of any other. 

We seined both in the canal and below the dams at Maduni Stop-Off and 
Lama Stop-Off. In all we secured forty-nine species, five of which were not taken 
elsewhere: Rhamdia holomelas, Ageneiosus brevifilis, Nannostomus simplex, Pristella 
aubynei, and Hyphessobrycon minimus. The first three are certainly found elsewhere 



36 



MEMOIRS OF THE CARNEGIE MUSEUM 



in the colony, and the fifth is a minute species imperfectly known from the few 
specimens secured. 

Although the Georgetown trenches are a direct continuation of the canal at 
Lama Stop-Off, we secured twenty-eight species at the latter point which we did 




Fig. 6. View on the right bank of the Demerara River. 

not get at Georgetown. Part of the twenty-eight have come from below the dam 
at Lama Stop-Off, but even this reach of water is but recently disconnected from 
the general system. 

From Lama Stop-Off we returned to Georgetown on the 19th of September, 
packed and forwarded the fishes collected to the United States, and prepared to go 
inland. Mr. Shideler left for Wismar on the 23d and I followed on the morning 
of the 24th. The steamer left Georgetown at 8 A.M. and reached Wismar at 4:30 
P.M. The water is muddy until Berlin is approached and becomes blackish 
further up. Wismar is about sixty-five miles above Georgetown in a straight line. 
The Demerara is navigable for ocean-going sailing-vessels to this point, and is 
affected by the tide to the first cataract at Malali, about one hundred miles from 
Georgetown, in a direct line. The entire region from Georgetown to Wismar is 
flat, except for occasional sand-hills. Creeks enter the Demerara from both sides 
about Wismar. At Christianburg a creek has been dammed and a canal brings the 
water to the sawmill on the river. We collected in the Demerara river at Christian- 
burg and at Wismar, in the Christianburg canal, and in the creeks emptying into the 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



37 



Demerara. It had become evident that during the heat of the day but few fishes 
could be taken in the shallow water of the main stream, so that from this time on 
the daytime was used to explore for likely places, which were then seined at night. 
Most of the mouths of the creeks about Wismar are provided with partial 
fences built of poles and palm or banana leaves. The center is ordinarily left 
open for the flow of the tide. A mat can be placed in the gap, which will prevent 
fishes from coming out of the creek. When the tide is high at night and fish have 




Fig. 7. View of creek, filled with brush- wood above Wismar at low tide. Indians are poisoning the creek. 

left the main stream and entered the creek the mat is put in place. In the morning 
when the tide is out the fishes trapped are either killed with a cutlass, or poisoned. 
Many of our specimens were obtained in this way. The creeks are so full of brush 
that all ordinary methods of fishing are out of the question. Trap-nets could 
probably be used effectively instead of the fence in the mouths of the creeks. 

Except in a very few favorable places the banks and shallows of the Demerara 
are so profusely overgrown with Caladium arborescms that the seine could not be 
used. I engaged fishermen to collect for me some distance below Wismar and had 
a creek poisoned at Kumaka, several miles above Wismar. From all of these 
places I secured ninety species, five of which were not taken elsewhere. The speci- 
mens not taken elsewhere are: Ageneiosus guianensis, Poecilobrycon harrisoni, 



38 



MEMOIRS OF THE CARNEGIE MUSEUM 



Acanthophacelus bifurcus, Archicheir minutus, and Steatogenys elegans. Of these 
A. minutus is known by but one specimen. The first three are new, and S. elegans 
is found in the Amazons. Mr. Shideler went up to the cataract at Malali but 
secured only twenty-three species, of which Myloplus asterias was the only one I 




Fig. 8. Fish-fence made of reeds and banana leaves on creek above Wismar. Indian with bow and arrow 

ready to shoot larger fishes brought up by poison. 

did not get elsewhere. A list of the fishes which do not extend so far inland and 
another list of those which do not extend so far down stream as Wismar are given 
later. 

On September 29th, at 5 :30 P.M., we took the train for Rockstone. Rockstone 
consists of an hotel, terminal station of the steamer connecting with the railroad, 
a small store, and a number of cottages for workmen. All goods for the gold-mines, 
and all rubber coming from the interior are transferred here to avoid the cataracts 
in the Essequibo below Rockstone. The Essequibo is here divided into two chan- 
nels by Gluck Island. At the time of our visit rocks were exposed at the stelling 
and a short distance below Rockstone. At the bend of the river above Rockstone 
there was an extensive sand-bar exposed. We collected at the Rockstone stelling, 
in the railroad-cut running into the river just below the town, in a small woodland 
creek on Gluck Island, and on the sand-bank at the bend above Rockstone. The 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



39 



richest ground was found in the brook on Gluck Island and the slough between the 
sand-bank and the shore of the river. A haul made at night on the sand-bar was 
also very successful. 

A portion of a letter describing my first day at Rockstone follows : 




Fig. 9. View on bayou back of Christianburg. Indian fishing from his corial. 

September 30th, 1908. 

" Very early in the morning I engaged two Indians who were on a balata boat waiting for a 
crew to go up the Rupununi. They did not know English, neither did they know how to fish, and 
I got exasperated, till Shideler went in to show them. Hereafter I shall always dress to go into the 
water myself. We worked faithfully along the stelling and below, with the poorest success I ever 
had anywhere. We could see fishes galore, one especially (Chalceus ?nacrolepidotus) lustrous plum- 
beous, with the most gorgeous, maroon colored fins, flaunted its colors in my face, but it was im- 
possible to get at it. At ten we came to the hotel, I completely dead beat, for this was the place 
where we were told we should 'catch fishes.' 

"As we were waiting for breakfast a band of Indians came along, a man and about six girls and 
women. After parleying it turned out that they were going to poison a creek. We asked them to 



40 



MEMOIRS OF THE CARNEGIE MUSEUM 



wait at the station till we could join them. We rushed through breakfast, caught our two Indians, 
who were just ready to eat their breakfast, and made them take it along, and then went after the 
fishing Indians, who started as soon as they saw our boat come out of the creek. After skirting 
Gluck Island some time they stopped at a creek so small that I thought it could have no fishes. 



..... 


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Fig. 10. Indian women pounding leaves in a hollow on the ground preparatory to using the pulp for poisoning 

a stream on Gluck Island. 



Two of the Indian women scraped a small depression into the ground, cut two sticks and used them 
as pestles and the depression as a mortar in which they pounded a basketful of leaves into a pulp. 12 
They then built a fence across the creek with palm leaves, scraped the mud from their mortar into 
balls and squeezed them into the water some distance up the creek. The Indians and myself were 
soon knee-deep in water and mud, picking up the fishes which came to the surface. The little ones 
died in numbers on the banks, the bigger ones revived. I had a set-to with the Indian women 
because they did not want to sell me all the catch. We finally compromised, and I took all I wanted, 
giving them the larger ones. I supposed they wanted several dollars, but they asked only two 
shillings. I gave them three and we were both happy. After my transaction with the women was 
completed, the man gleefully held up a fine luckananee he had shot with an arrow. 
12 1 regret to say that I did not get the name of this poison. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



41 



" On the way home we stopped on some rocks, dikes that run across the river, and secured 
crabs, and another Loricaria. 

" I ate dinner with a somewhat better feeling, but determined to use our big hundred-and-fifty- 
foot net at the sand-bank after dinner. The porters were all gone when we got to the station, but 
I was able to pick up a couple of negroes, and took one of our Indians. Mr. Kingsland, the agent 
at Wismar, went along. The crew played the most interesting tunes with their paddles. When- 
ever he felt like it, the leader, by a peculiar stroke with the paddle, would get all of them to hit the 
boat during a definite part of the stroke. It produced surprising results and varied the monotony 
of the long row. After we had gone what I thought twice the distance, we discovered that by staying 
on the wrong side of the river we had overshot our mark and had to go back. Soon our boat got 
stuck in the mud at the upper end of the bank, but finally landed on a place that must have been 
made for us. It was a shallow bay on the upper end of the sand bank, a hundred and fifty feet 
across with a sandy bottom. We stretched the big net across and hauled out at the head of the bay. 




Fig. 11. Small stream on Gluck Island dammed by Indian women before putting in the poisonous leaf-pulp. 

Fish flopped in every direction, dozens went over the net, one of them went at one of the men and 
made him jump. At the critical moment the enthusiasm got the better of even our Indian, and he 
ran ashore with the top of the net and let half the catch out. As it was we had two buckets full of 
specimens. I gave Mr. Kingsland a luckananee weighing seven pounds, and the crew had enough 
to make the haul historic for all time to come. We got home at 12:30 A.M." 13 

13 1 recognized seventy-one species on the day following. The number was probably nearer ninety, for 
in the final examination I found I had taken sixty species in two or three hours out of the small brook on Gluck 
Island. 



42 



MEMOIRS OF THE CARNEGIE MUSEUM 



The first day of October until evening was devoted to sorting and preserving 
fishes. Prochilodus gave us much trouble. Full strength alcohol and formaline 
injected did not keep these specimens from beginning to decay. In the evening we 
seined on the rocks of the stelling and in the railroad-cut mentioned above. At the 
stelling we caught so many Hemidoras carinatus and allies with erected spines that 
it took us a long time to untangle them from the net. Each pectoral spine of these 
catfishes is provided with retrorse hooks, the spines are erected when the fish feels 
himself caught, and each spine must be individually disentangled from the net. 

On the second of October we went to the Rockstone sand-bar with our two 
Indians. We were soon joined by seven porters who came from Rockstone to get 
sand and who helped us pull the large net at the lower end of the sand-bar. The 
most important captures we made consisted of specimens of Geophagus carrying young 
in their mouths. The outer edge of the bar was almost barren, but yielded a few 
minute, translucent specimens of Characidium, which so closely resemble our sand- 
burrowing darters that they amply repaid for the water-hauls. But the greatest 




Fig. 12. Edge of bayou between right bank of Essequibo and outlying sand-bar at Rockstone. 

success was obtained in a bayou between the upper half of the bar and the land. 
Here we collected a large number of small fishes. The Indians took half a bushel. 
There is a great general similarity between the contents of the net here and one 
drawn at any similar locality in the Mississippi valley, although not a single species 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 43 

or genus occurring in the Mississippi valley was found in the catches. Here we 
secured the only specimen, greatly mutilated, of the widely distributed Sy?nbran- 
chus, and the young of many species of large fishes. Before starting for the sand- 
bank I had an opportunity of securing a lau-lau, but in the hurry of getting off, 
and on account of a momentary fit of penuriousness, I took only the head. 

On October third I returned to Wismar to make purchases for our trip to 
Tumatumari, and incidentally arranged to have a creek "stopped." I returned to 
Rockstone in the evening and sent Mr. Shideler to bring over the catch the next day 
at 2 P.M. Among other things he brought the rare Rhamphichthys. It is a long- 
snouted, sword-shaped, gymnotid eel. 

On October 4th I watched some of the natives dynamite about the Rockstone 
stelling and packed most of our catch for shipment. 

In the work of enumeration, which has taken two full years since my return, 
I find that Rockstone, where our fishing began so discouragingly, is the richest in 
species of all the localities examined. This was no doubt due to the fact that con- 
ditions for collecting were favorable. The water was low and we fished exhaustively 
in a variety of places. No doubt many channel fishes living here we did not get. 
Pseudoplaty stoma, Phractocephalus, and others, should be found there. Altogether 
we got one hundred and thirty-three species, eighty-three of which were characins. 
Of the one hundred and thirty-three species fourteen were not taken elsewhere: 
1. Xenacara gymnorhynchus. 2. Hemiodontichthys acipenserinus 

3. Aphiocharax melanotics. 4. Aphyocharax erythrurus. 

5. Mcenkhausia megalops. 6. Hemigrammus iota. 

7. Hyphessobrycon rosaceus 8. Hyphessobrycon riddlei. 

9. Hyphessobrycon gracilis. 10. Phenacocharax hemigrammus. 

11. Acestrorhynchus nasutus. 12. Rivulus lanceolatus. 

13. Rivulus frenatus. 14. Crenicara punctulata. 

Some of these are known to have a very wide distribution. Number 2 for 
instance, extends to Paraguay; Nos. 6 and 9 are found in the Amazon; No. 8 
in the Orinoco. Others are known only from the specimen collected. A critical 
examination of this list of uniques thus shows that these lists mean nothing except 
what is on the surface. 

On Monday, the fifth of October, we started for Tumatumari, but on account 
of various accidents to the boats we had to tie to the shore over night. Being 
overtaken on the following day by another boat, we went on with it to Tumatumari. 
which we reached at 7:00 P.M. I called on Mr. Edward Bovallius, the representa- 
tive of the Essequibo Exploration Company, and on Mr. Brummel, one of the 
government officers, and began seining on the following morning. 



44 



MEMOIRS OF THE CARNEGIE MUSEUM 



Tumatumari owes its existence to a cataract in the Potaro River. The goods 
brought up by the launch to the lower landing are transported by cart to the upper 
landing, and this transport gives employment to nearly all the inhabitants. At 
the time of our visit the stream was confined to the northern channel, the southern 
channel being entirely dry. We made headquarters in the Sproston's rest-house, 
from which point we had a view over the cataract. We collected on sand-bars 




Fig. 13. Looking across the Rapids of the Potaro River at Tumatumari. Papaya-trees in foreground. 

above and below the cataract, in the cataract itself, and in a little stream emptying 
from the north just below the cataract. Our experience in fishing may again be 
quoted from letters sent home. 

"We found a brook and went up it. I enjoyed the water, it was nice and cool. The water 
we have to drink is in an iron tank out in the broiling sun and no ice is to be had nearer than forty- 
seven miles. We fished upstream until we came to a deep pool. The nondescript helping us did 
not know "how," and stepped on a spiny palm branch besides, so I got into the water to take his 
place, and told him to take a big club and beat the water to drive the fishes down. He did this 
slowly. Shideler and I then took up the lead line of the net, for the banks were so steep and full 
of snags there was no place to haul the net ashore. We were walking down stream with the bag 
of the net in the water to a place where we could land, when Shideler said, "I believe we have an 
electric eel, for I have had two slight shocks." 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 45 

" I envied him, but too soon, for just then I got a good shock from ankle to knee and I jumped 
and yelled, not so much from pain as from the unexpectedness of the shock. 

" We found we had five eels in the net, the largest three feet long, and it took maneuvering to 
get them into the buckets. I received several more slight shocks before it was accomplished. 

" We rested in the afternoon, so as to be ready to go out at night. It is scarcely possible to 
catch anything in the river in daytime. We were simply looking about to see where we could haul 
at night. In crossing the river at night I think our boat struck half the sunken rocks, until I in- 
sisted that the water be baled out before we risked another shock. On the sand-bank across from 
the lower landing we caught two more electric eels in a net well filled with fishes. It was surprising 
how soon everything became quiet in the flopping netful of fishes with such customers in their 
midst. I opened one of the eels and found small fishes in its stomach. I put a twig through the 
gill of the largest eel, for we proposed to eat it; the other eel we wanted to take home alive to see 
some sport, and I placed it in a live-net. I had the eel in one hand, and in order to pick up the net 
put the lantern in the same hand, but as soon as the lantern touched the eel I got a shock through the 
handle. It was not a heavy shock, but I did not know how much heavier it might become, and so 
gave up that way of managing. 

" When I came to pick up the net containing the other eel, I got another slight shock, and con- 
cluded I needed help to carry them. We ate part of the largest; the electric organ was pasty 
and the rest was so full of bones that we did not succeed with it. 14 

"Thursday morning Shideler went to fish above the falls preparatory to fishing at night. I 
took care of the fishes, but by night we were both so tired we postponed the fishing till Friday night, 
when we caught a seven pound luckananee, which, profiting by previous experience, we skinned and 
ate. On one haul our net was again full of Hemidoras. These became so tangled up in the net 
that it took an hour or more to get them out. One of them was new (Leptodoras linnelli)." 

On the 10th of October T went to Potaro Landing to make arrangements to 
ascend to the Kaieteur. Mr. Shideler went up, the next day to watch some poison- 
ing, but returned in the afternoon with Mr. Linnell, who had come down from 
Holmia with a crew of Indians. 

Mr. Linnell, the representative of the Essequibo Exploring Company at 
Holmia, and Mr. Bovallius, the representative at Tumatumari, after consultation, 
lent me the crew of Indians which brought down Mr. Linnell, under the Indian 
captain William Grant. They also placed their bateaux between Kangaruma and 

14 The "numb fish" early excited the interest of naturalists and thus directed attention to the fish- 
fauna of the Guianas. The first notice of the fishes of the Essequibo was an account of the doings of the 
electric eel, and in the second paper Bancroft attributed the shocks delivered by the electric eel to electricity. 
Humboldt described how his assistants drove some horses into the water to exhaust the eels. It became 
generally accepted that this was the usual method of fishing, although it is doubtful whether this method was 
ever tried except on the occasion when Humboldt did it. 

A comprehensive account of the electric eel was published by Sachs as a result of a trip to Venezuela 
for the special purpose of studying it. " Aus den Llanos," Leipzig, 1899, and " Untersuchungen am Zitteraal," 
Leipzig, 1881. 



46 



MEMOIRS OF THE CARNEGIE MUSEUM 



Holmia at our disposal. Our success on the expedition to the upper Potaro was 
largely due to the cooperation of Messrs. Linnell and Bovallius. 

We started on a launch from Tumatumari on the 14th of October at nine 
o'clock in the morning. We were met at Potaro Landing by part of our crew, 
who carried a portion of our outfit about seven miles to Kangaruma. The crew 
returned to Potaro Landing the following day for the remainder of the goods. The 
latter part of the trip between Potaro Landing and Kangaruma was through the 
forest, the first two miles through a hot sandy road. I felt a slight fever on arriving 




Fig. 14. Albert, one of the Indian bearers, transporting goods at Kangaruma. 

at Kangaruma. The portage from Potaro Landing to Kangaruma, which can be 
made in two and a half to three hours, obviates the engagement of a series of 
cataracts between the two points. We left Kangaruma in the afternoon by a 
peculiar bateau. A tarpaulin covered the center of the boat where our goods were 
stored; in front sat three pairs of paddlers; behind several more paddlers. William 
was captain and steersman as well, until we picked up a corial at Amatuk and 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



47 



"Trenchan" became steersman. Eddie, my cook, spent his time largely with the 

dog "Sunday." Part of our Indians were jolly, naked savages from near Holmia; 

the others were surly fellows dressed in shirt and trousers and had come from Brazil. 

After about two hours rowing we camped beside a creek, Erukin. I attempted 




Fig. 15. View looking up the Potaro River in the early morning. Glimpse of the Guiana Plateau in the 

distance. 

a little fishing at night, but with the very poorest success. On our return trip we 
were more successful at this point. 

On Friday, the 16th, we started at 6 A.M., and by eight were at Amatuk, where 
we remained till breakfast. We attempted to do some collecting on the sand- 
bank, but, as usual in the daytime, with very little success. At Amatuk the goods 
had to be carried to a boat above the twenty-five foot cataract. I had felt fine 
all the morning and enjoyed especially the lazily flopping Morphos crossing the 
river, and the flying fishes. The latter would dart up in front of us, cut through 
the water, leaving the breast or tail in the water and beating the water with their 
pectorals. One of the flying-fishes would cut through the water for forty feet or 
more and then leave the water entirely for five or ten feet. At the end of its 
flight it would fall sidewise into the water. At first it looked like a long, slender 
fish, but by watching near the end of the flight, when the momentum was gone, 
the disc-like shape could easily be made out. To make sure I asked the Indians 



48 



MEMOIRS OF THE CARNEGIE MUSEUM 



to point out the fish when we seined. William pointed out a long, slender Creato- 
chanes, but the naked hunter shook his head, and with thumb and forefinger made 
a circle. We caught none in the Potaro, where we saw them frequently, but got 
them in abundance in the lower Demerara. Gasteropelecus is more apt in its 
flight than Carnegiella. Whole schools will sometimes leave the water and shoot 
over the surface. 

After breakfast we rowed up through the gorge, which the Potaro has cut 
through the table-land beginning at Amatuk. The edges of the gorge have been 



. yte a 


. 










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Fig. 16. Seining on a sand-bar below the Amatuk Cataract. 



carved in a variety of ways which give them the appearance of high mountains. 
The valley is quite broad, indicating the great age of 1 he gorge, which is a thousand 
feet deep. 

We took with us a corial from Amatuk, planning to send Mr. Shideler back 
in it from the Kaieteur. The Indians shot a baboon on the way up to Waratuk, 
the next portage. We camped rather early in the day above Waratuk and during 
the night I had a particularly nasty case of chills and fever. By midnight I could 
scarcely stand, but enjoyed the great variety of new noises from the water and 
forest. 

We started at 7:00 A.M. on the 17th and stopped at 8:00 to get our first 
glimpse of the pride of Guiana, the Kaieteur. The Kaieteur was hidden in mist 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



49 



so early in the morning. We camped shortly afterwards at Tukeit, called "Tukui," 
or humming-bird, by the Indians, after the waterfall coming from the plateau 
opposite the camp. Our hunters killed four peccaries across the river, and young 
wild pork was a pleasant change from the canned meats. At Tukeit there is 
another cataract in the Potaro, and above it several more towards the foot of the 
fall. It is one of my regrets that time did not permit me to walk up to the Kaieteur. 
We collected in the Potaro at Tukeit and the following morning at eight 
started to ascend the plateau. The path leads back from the river for a time, 
crosses Shrimp Creek, and then ascends very steeply to the top of the plateau. 
Here it is comparatively level again and runs through the woods to the edge of 
the sav. nnah, or treeless tract, immediately about the fall. 




Fig. 17. View on the Potaro River looking up stream at the point where the first glimpse of the Kaieteur 

Falls is caught. 



After breakfast, at the edge of the savannah, Mr. Shideler and I, with William 
and another Indian, walked to the edge of the precipice and to the fall, while the 
rest of the Indians went on to pitch the camp and get the boats of the upper Potaro 
ready. 

The scenery about the fall is unique. Looking down the stream one sees 



50 



MEMOIRS OP THE CARNEGIE MUSEUM 



the U-shaped gorge cut out by the Potaro in the level plateau. The Potaro is 
visible from time to time as it crosses from one side of the valley to the other. The 
best view of the fall itself can be had by climbing down on a ledge of rock at the 
edge of the precipice. I not only climbed down, but, all excitement with the fever, 




Fig. 18. Exposed left side of the bed of the Potaro River at Tukeit in the dry season. 

the steep climb, and the superb view, set up my camera on the ledge and took 
numerous photographs. I confess to feeling distinctly dizzy when I placed my 
head under the focusing cloth, knowing that if something should happen I and the 
camera would land on the rocks a thousand or so feet below. Not that I could 
find a finer place to die, but I was reluctant to start to " kingdom come " on such a 
heavy down grade. 

After making about thirty exposures under varying conditions, we went to 
the camp in the bush some distance up the river. The fall is caused by an exces- 
sively hard conglomerate which overlies a softer sandstone. The savannah above 
the fall is in large part this naked conglomerate. In places bushes grow from 
cracks in the rocks. Many bunches of grass, or flowers grow from a little accumula- 
tion of soil that can be kicked from place to place along the surface of the rock. 
The afternoon of the 18th and part of the 19th were devoted to fishing and packing. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



51 



Mr. Shideler started down for Georgetown at 11:00 A.M. of the 19th, with three 
of the Indians. He collected about Potaro Landing, in the Botanic Garden, at 
Bartica and near Morawhanna, Issorora, etc., of the northwest coast. The crew 
who remained with me was divided between two boats. One boat, the "balahoo," 
was dispatched at once with the goods, while a few of the Indians, with William 
and myself, stayed till the following morning. 

We started after the other boat on the 20th, at 6 A.M. It rained hard. All 
hands pulled with all their might on this, the home stretch. We reached the regular 
camping site at 3:00 P.M., but all the Indians were anxious to go to Holmia, which 
they said they could make in three hours. I was willing. By a supreme effort 
the three hours were cut down to two hours and twenty minutes, and at 5:20 P.M. 
we reached Holmia. 

Holmia is the trading camp of the Essequibo Exploration Company. The 











*^m •fjitd^A 





Fig. 19. Looking up the Potaro Valley from the brink of the Kaieteur Falls. 



company has a store and depot surrounded by a few Indian huts. It is situated 
on the Potaro at the entrance of the Chenapowu river. My crew of Indians went 
out at once to collect poison, the root of a plant called "hiari" (?Lonchocarpus) 
under the guidance of the local Indian, Jordan. The Indians of the surrounding 
regions brought me fishes and we ourselves poisoned a small creek just below the 



52 MEMOIRS OF THE CARNEGIE MUSEUM 

houses. Unfortunately, it rained heavily, so that the Chenapowu and the Potaro 
rose many feet and made fishing in them not profitable for some time. We went 
up the Potaro a distance further and poisoned two creeks just below the Aruataima 
cataract. In the cataract itself we could do nothing on account of the high water. 
William later collected in the cataract and sent me two new genera and three new 




Fig. 20. Looking down the Canyon of the Potaro River from the brink of the Kaieteur Falls. 

species, from which it would seem that further collecting would prove profitable 
at this point. 

The character of the fauna of the plateau is discussed in detail in another place. 
It seemed that each creek we examined contained some one dominant form and a 
few stragglers. The dominant forms varied in different creeks. 

I started from Holmia on October 27th, fully intending to return with Mr. 
Linnell, but I found at Tumatumari that he had gone to England, and I did not 
return. That I could go no further on the Potaro, could not cross over to the 
Ireng, is a lingering regret. We reached Savannah Landing at 12:00 and walked 
over to the Kaieteur to take a few more photographs. 

We also poisoned another creek and collected in a swamp above the landing. 
We started down for Tukeit at 1 :30 on the 29th of October. In crossing Shrimp 
Creek, which seemed quite impossible as a fish habitat, I caught a Rivuhis with 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



53 



my hand. I was surprised by the catch and more so by the sequel. The fish 
jumped out of my hand and stuck to a vertical rock by its tail and jumped from 
this to another point higher up on the same rock. It was lost on the way down to 
camp, so I sent William back the next day to poison the creek. He secured two 
species of Rivulus {waimacui and breviceps) and a Characidium (vintoni), all of them 
new. We collected about Tukeit in the afternoon, poisoning the creek just below 




Fig. 21. View looking up the dry bed of Shrimp Creek. Figure of man in middle distance shows the height 

of the rocky steps. Follow indices on cut. 

the landing with considerable success. The striking thing about the fauna at 
Tukeit is its evident contamination by the fauna of the plateau. Helogenes and 
Poecilocharax, fishes of the plateau, are found at Tukeit below the Kaieteur, but 
were not taken lower down. 

On the 30th we started down the river. While the Indians were transporting 
the goods at Waratuk I experimented a while with poison in a little side branch of 
the cataract. I was so successful that I proposed to make a more systematic 
attempt at Amatuk, where we stayed for the night. We poisoned above the 
cataract on an island, but without great success. Below the north branch of the 
cataract we tried once more on the morning of the 31st. Some of the water loses 



54 MEMOIRS OF THE CARNEGIE MUSEUM 

itself here under rocks, and we placed the poison above the point where it runs into 
the rocks. The branch was entirely too large to enable us to kill the fishes, but 
the poison drove them out from under the rocks so dazed that we could pick them 
up with our dip-nets. 

In all we took forty- two species, of which five were not found elsewhere : 1. 
Brachyglanis frenata, 2. Brachyglanis phalacra, 3. Hemicetopsis minutus, 4. Pseud- 
ancistrus nigrescens, 5. Characidium laterale. All of these were new. 

Here I also secured a series of related little catfishes that were either confined 
to, or most abundant in, the cataracts of the lower Potaro. These are Brachyglanis 
frenata and phalacra, mentioned above; Myoglanis potaroensis and Chasmocranus 
longior and brevior. Other Pimelodinw, Doradinw, and Auchenipterinoe were ab- 
sent. Lithoxus, a little loricariid catfish, was very abundant. It is flat and clings 
to the rock, which is greatly resembles. They were especially abundant in rather 
deep pools and could only be seen when the poison brought them fluttering to the 
surface. Loricaria was not observed. Deuterodon pinnatus and potaroensis were 
also abundant in the cataract, and Po?cilurichthys abramoides and Mquidens potaroen- 
sis occurred in a shallow pool near the margin. 

Tetragonopterine characins were scarce, but one representative of the Ser- 
rasalminai was taken. Of the Characina? there were none. The peculiar Sternar- 
chorhynchus oxyrhynchus, Porotergus gymnotus, and Sternarchus leptorhynchxis were 
seen here for the first time. They were among the rocks and were driven out by the 
hiari. The following letter preserves the impressions of this region in their freshness : 

Kangaruma, October 30, 1908. 

" I think I have written everybody and answered all questions, which need answering, so I may 
continue my record. 

"I awoke before five, and as some of the Indians were stirring I began to sing "balahoo," re- 
peating the word to an old college tune. It has been the reveille and march for the crew ever since 
we first reached the Kaieteur. I learned several tricks yesterday in poisoning Waratuk that I 
proposed to put in execution today at Amatuk. We first tried poisoning a little branch above the 
fall at Amatuk, and got some things. Then we tried a more ambitious scheme of poisoning a 
big branch below the fall. I found that the poison will drive some fishes out before it kills. We 
had three men pound hiari and wash it into the branch of the northern part of the fall. William 
and another Indian stood a long distance below after the water had flowed among and under rocks. 
I at first stayed near a pool where they were poisoning. Soon Plecostominw began to come up. 
They were new to me and I dipped with enthusiasm until I fell in. This broke the ice for me, for 
I then waded from rock to rock, securing eighty-seven specimens of the new genus Lithoxus. William 
came with a dip-net full of fishes, among them long curved-snouted Gymnotidce I had not seen. 

"We poisoned and waded, gathering in all half a bucketful of small fishes, all valuable as speci- 
mens. It was rare sport, and I did not realize that it was ten o'clock and that I was played out 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 55 

We had soup, rice, tea, and jam for breakfast, and started at 1 1 :30 on the home-stretch. Dead fishes 
were floating about the little bay from which we started, so the poison kills. 

"Most of the Indians had done nothing but swing in their hammocks all the morning, so they 
paddled with a swish and swing in great contrast to yesterday's dilly-dallying. At one P.M. we 
were at Erukin, a sandy, clear creek that I wanted poisoned. We had fished here with poor success 
at night on the way up. William thought it was too big and swift to poison, but I had them stretch 
the net across the mouth, sent the pounders up-stream, and William, some other Indians, and myself 
took up stations at intervals obliquely across the river. I stood in a patch of sunlight where every 
grain of sand could be seen at the bottom. I was in sleeveless undershirt, pants, and a pair of socks. 
My tennis-slippers had gone to pieces on the rocks at Amatuk. Soon fishes came down the stream 
in distress, and when the poison was exhausted, we found we had a number of novelties in our dip- 
nets and the fifteen-foot net at the mouth of the creek had caught most things as they came down. 
At 2:30 we were moving again, and when near 4:00 o'clock William cried out "Kangaruma," all 
paddles stopped for a moment and then dashed on, and we landed here at 4 P.M. 16 I read let- 
ters, not all of them thoroughly, till supper time. I must wrap and pack my fishes before we 
start on our two-and-a-half hours' walk to-morrow, for I don't want to lose the day's catch during 
the walk. 

Saturday morning. 

" For about a month now I have not slept out of hearing of the roar of the cataracts. Tumatu- 
mari, Kangaruma, Amatuk, Waratuk, Tukeit, Kaieteur, and Holmia are all on cataracts or falls. 
In fact they are all places where goods have to be transported on account of cataracts. I have so 
much stuff that it took more than one trip for the twelve carrying Indians that have come down with 
me. But then their food and personal effects add a little. My personal effects make about one 
load now. The trip has been a phenomenal one. I can't say that I could swear that I have every- 
thing, but every effort, seconded in each case by William and sometimes suggested by him, has been 
made. I ought to have poisoned the cataract above Holmia, but it rained a night and a day so the 
river rose five feet, and it could not have been done even' if I had at that time learned the trick." 

We left Kangaruma in the morning of November 1st for the walk through 
the woods, and arrived at Potaro Landing in time to catch the boat for Tumatumari. 
Here I parted with my crew, who returned to Holmia with Mr. Bovallius. I 
packed fishes and had the fever again. I broke it, and left on the 4th for Crab 
Falls. 

The Potaro Gorge is one of the remarkable features of the world. The river 
is lined with trees so tall they could only thrive in a region free from strong winds. 
The sides of the gorge are rugged, and the whole recalls the Rhine, or the Yosemite. 
We saw no one from the time of striking into the woods behind Potaro Landing 
till we reached Holmia. The entire stretch is utterly uninhabited and very few 
tourists pass this way to get the inspiring view of fall and gorge from its upper 
brink. The region between Savannah Landing and Holmia is level, but mountains 

15 Mr. Macturk had brought a batch of letters from Georgetown and left them here. 



56 



MEMOIRS OF THE CARNEGIE MUSEUM 



can be seen in the distance, toward the south, when the view is not obstructed 
by trees. 

The fauna of the Essequibo becomes attenuated as we go up the Potaro. Its 
upper course below the fall undoubtedly contains intrusives from the plateau which 
decrease in number as one gets further and further from the Kaieteur. 

At Tumatumari I boarded the launch, taking with me a negro, Mr. Cum- 
mings, with a bateau. We landed at the head of an island a short distance below 
the mouth of the Potaro and just above Crab Falls. There was an Indian settle- 
ment here. We slung our hammocks under the shelter of one of their huts. My 



WIDTH 552ft 

600 FT WIDTH 369 FT 



1320 FT 




^■822 FT 



Fig. 22. Diagrammatic representation of the contour of the Kaieteur Falls. (After Brown.) 

own hammock, that of Mr. Cummings, and that of an Indian woman radiated 
from the same center pole, at the base of which a monkey was tied, — a cosmopolitan 
quartet. Cummings and the Indians went out with the net at night to fish on the 
sandbanks. I remained in my hammock to recuperate from the fever. On the 
fifth I sent several of the Indians out to dig hiari roots while I fished about the rocks 
of Crab Falls. The Essequibo is very wide at this point, divided by an island, and 
falls over a dike running squarely across the river just after it has made a turn. 

On the sixth, Cummings, myself, and four Indians went with the bateau up 
the Essequibo to shoot pacu at the Warraputa Cataract. Above the mouth of 
the Potaro the Essequibo is broken by a large number of rocky islets, fragments 
of a dike crossing the river. Other dikes cross the river further up, the water 
rushing through the gaps. Through some of the gaps the Indians succeeded in 
paddling the bateau, through others they dragged the boat after being driven back 
several times by the current. 

A dike extends across the Essequibo near the mouth of the Konawaruk. 
Opposite the Konawaruk and below the dike there is a lagoon separated from the 
river by a sandy and partly wooded spit of land, but connected below with the 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 57 

river. Near the head of the bayou and connected with it by a few inches of water 
there is a pool toward the river side. It is not more than fifty feet in diameter 
and perhaps six feet deep in its deepest part. Trees overhang it from the river 
side. The Indians pounded hiari roots into shreds. They were tied into bundles 
and two Indians boys swam through the pool with them to mix in the poison. 
I have described the effect in the introduction. First one species and then another 
came to the surface, and then they came indiscriminately. A stingaree came 
fluttering to the surface toward the last, while the little Corydoras punctatus with- 
stood the poison to the end. Catoprion mento, a Mylinid characin with a projecting 
chin, was particularly acceptable. The fish that created the greatest interest was 
Mcenkhausia dichrourus, of which I had seen dozens of specimens, hailing from dif- 
ferent localities all the way from Paraguay to Para, and all of them conveyed about 
as much idea of the appearance of the living fish as a dead and plucked Baltimore 
Oriole would give of the living bird. The base of the tail is bright canary-yellow, 
the lobes are crossed with jet-black bands and the tips are milk-white. 

I do not know how long we stayed here, not over two hours, in which we 
caught fifty-five different species of fishes, six of which were not secured elsewhere. 
The uniques were Bunocephalus amaurus, Ochmacanthus flabelliferus, Odontostilbe 
melanditus, Aphyodite grammica, Hyphessobrycon minor, Dormitator gymnocephalus, 
all of them new. Several other new or rare things were taken in only one other 
locality: Porotergus gymnotus, Catoprion mento, Hemiodus semitceniatus. 

We continued our row to the Warraputa Cataract. The river is divided 
here into several branches by wooded islands. The two older Indians started 
out to shoot pacu, but bagged nothing. The rest of the crew and myself set to 
work to poison a branch of the cataract, where we were again quite successful, 
securing a series of specimens that recalled the Amatuk cataract. We also got a 
series of the young of the pacu, the first which were obtained or recognized as such. 
The color changes in the young can be seen in plate LIX. After the poisoning Cum- 
mings went to the sand-bank to prepare supper, while I browsed about the cataract 
with the two young Indians. 

On my return at dusk I found that no provision had been made for my ham- 
mock. The Indians declined to go into the bush at night to secure palm- 
branches and I did not like to risk a drenching rain so soon after having had 
the fever. I insisted that the Indians either build me a shelter or take me 
back to their camp. Giving them an alternative was a mistake. They de- 
cided to take me back. It did not rain that night. It was all very well to come 
up through the gaps in the dikes in the day time. It was quite another matter 



58 MEMOIRS OF THE CARNEGIE MUSEUM 

to safely guide the bateau down through them at night. We shot through at a 
tremendous rate and once the boat touched something. The boys shouted with 
glee, while I came to a sober realization that it would have been better to trust the 
sky than the rapids. But we got safely back to the huts early in the evening. 

On the seventh of November I collected about the rocks just above the fall. 
Here I succeeded again with hiari in getting fishes which could have been secured 
in no other way. At one point the bank is piled with huge blocks of stone. To 
dislodge the fishes from between them would have been impossible in any ordinary 
way. We pounded some hiari roots and washed them in the swift current that 
was flowing towards the rocks. At once some species came to the surface, straight 
up, without attempting to escape. Several species were dislodged including an 
electric eel. We repeatedly got it into our dip-net, and it as often got out again, 
without, however, making any coordinated movement to escape from the reach of 
the net. It proved too slippery, however, to hold in the net, and it got away. 
When the launch came by from Tumatumari we loaded my effects into it and I 
left the region of the Potaro and upper Essequibo. I landed at Rockstone in the 
afternoon and took the train for Wismar the next morning. After packing fishes 
all clay I went to Christianburg as the guest of Messrs. Spence and Brummel. On 
the ninth I rested at Christianburg. The tenth Mr. Brummel took me to Kumaka, 
where I made arrangements to have a creek poisoned, and on the morning of the 
eleventh I took the steamer for Georgetown. 

Visiting the markets, preserving and packing fishes, suffering a relapse, re- 
covering from the fever, and enjoying the hospitality of friends at Georgetown 
consumed the time until sailing for New York. Everything collected arrived at 
home safely. 

Method of Preserving. 

The method of preserving the fishes, not one of the twenty-five thousand of 
which was lost through decay in this tropical region, was as follows: 

In the Essequibo and the lowlands all fishes except large catfishes were dropped 
alive into a can of 25-35 per cent, alcohol in which they were killed. Minute 
fishes were placed in vials or in small bottles instead of in the tank. Shortly after 
reaching the camp or home all the fishes above two inches were injected with 95 
per cent, alcohol, freed from the coagulated slime, and placed in a can with about 
50 per cent, alcohol. The first alcohol, if less than 25 per cent., was thrown away; 
if more than 25 per cent, it was allowed to stand and was decanted to be used again. 
A day or two following the catch the specimens were transferred into 75 per cent, 
alcohol and the larger ones again injected. The following day they were roughly 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 59 

sorted, wrapped in cheesecloth and dropped into 85-95 per cent, alcohol. As soon 
as sufficient material was at hand to fill a kerosene can or two, they were filled with 
fishes packed tight as sardines and the can soldered. A small hole was then punched 
and the can filled to the top with 95 per cent, alcohol, and again soldered. 

Two cans were usually packed in an original kerosene-can box and shipped at 
once to New York. Some of the cans were punctured and the alcohol leaked out 
on the way home. The fact that these also brought the fishes through in perfect 
shape showed that ordinarily greater precautions were taken than necessary. 

Because some one who knew nothing of the Indians told me they would steal 
the alcohol, I took only formalin beyond Tumatumari. I regretted it much, 
because the precaution was not at all necessary and it would have been better to 
have had all the scaled fishes preserved in the same manner. 

In wrapping the fishes for packing the usual precaution was taken. A locality 
label was added to each little bundle and the fishes were so wrapped that a layer 
of thin cheese-cloth was between every two. Care was always taken not to tie 
the bundles too tightly, and minute delicate things were placed in a small vial after 
being wrapped Smaller specimens after being wrapped were packed in empty 
one-pound coffee-tins to keep them from being crushed in the larger kerosene 
cans. 

Naked catfishes in general were preserved in formalin and transferred to 
alcohol at home. They do not have metallic tints which are dissolved by the for- 
malin, and retain their plumpness better than in alcohol. But the difficulty in 
opening the jaws and the danger of damaging the fins probably fully dis- 
counts for all the gain. 

Color notes upon the characins were preserved. It was not possible to do 
more at the rate I was collecting. The difficulty with Prochilodus was mentioned 
above. 



CHAPTER IV. 

THE GEOGRAPHICAL DISTRIBUTION OF THE FRESHWATER FISHES OF 

BRITISH GUIANA. 

Every effort was made to secure a complete series of the fishes of the area 
covered, and reasonable success may be claimed, the ichthyic fauna at large being 
well represented by the eighteen thousand three hundred odd specimens collected. 

Inasmuch as several localities were examined in each of the following districts, 
(1) the lowlands, (2) the middle Essequibo, (3) the lower Potaro, (4) the upper 
Potaro, we may also conclude that the faunas of these stretches of territory are well 
illustrated by the material collected. Furthermore, the work on such units of 
environment as the trench in the Botanic Garden, the woodland creek and sand- 
bank at Rockstone, the Konawaruk pool, and the Amatuk Cataract was entirely 
satisfactory. 

On the other hand, it may be doubted whether the lists of specific localities 
are in many other cases exhaustively complete. I have called attention to this 
matter in connection with the species taken at Rockstone and nowhere else. It was 
found that many of these are known to have a wide distribution and must occur 
in other localities in the area under consideration, although they were not taken 
elsewhere. 

Furthermore, it must be regretted that time did not permit me to make a 
more exhaustive study of the fauna in the Potaro between Amatuk and Tukeit 
and" above the Kaieteur. 

General Plans for Distributional Work. 

A question of greater interest to the next expedition than to the general account 
of the present trip is the length of time that should, and could to advantage, be given 
to any one place, and how far apart stations should be selected. To graphically 
demonstrate conclusions I have prepared two tables. - 

On p. 84 is a summary showing the total number of species taken at each place, 
and on p. 85 a summary of the number of species taken at but one locality. The 
latter shows how much would have been lost from the total number of species, had 
any particular locality been skipped. Only Kangaruma yielded nothing new, and 
fishing here was but a minor incident. There is very great inequality. The omis- 
sion of Konawaruk, where two hours were spent, would have entailed nearly as 

60 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 61 

great a loss as the omission of Tumatumari, where a week was devoted to fishing. 
Amatuk also, where fishing was attempted twice in passing up and down the 
Potaro, yielded a large number of unique species. 

At Konawaruk we stopped for only about two hours on our way up the 
Essequibo. Our success here is chargeable altogether to the fact that everything 
was gathered that was contained in a small sand- and mud-lined pool. A week's 
stay would not have yielded more. No doubt the list for this locality would have 
been vastly increased if we had as thoroughly cleaned out one of the rapids, a sand- 
beach, a fallen tree-top, a woodland brook, a rock-lined pool, the channel, etc. 
As far as possible one of each of such different units should be exhaustively fished 
at each locality if the limits of the distribution of species is sought. Superficial 
fishing yields only the ordinary, the cream is obtained by stripping. The length 
of time that should be devoted to any one locality depends, therefore, on the variety 
of units to be found at one place. Rockstone shows a larger number of species 
in the preceding lists because a greater variety of units were examined. Further 
collecting at this place would have been profitable. 

Again, to determine the limits of the distribution of species, localities should 
be no more than twenty-five miles apart in a stream like the Essequibo or lower 
Potaro. The distance between stations should of course be much less where the 
stream is descending rapidly. It may be greater if the largest number of species 
in the shortest time is the object. Rockstone and Crab Falls are about forty-five 
miles apart in a straight line. Sixteen species taken at Crab Falls were not taken 
at Rockstone or below Rockstone. Their downward limit was therefore not 
determined. About twenty species taken at "Rockstone do not extend as far as 
Crab Falls, and their upward limit was therefore not determined. It is doubtful 
whether anything else of consequence was missed, because the stations were so far 
apart. Over twenty-five species taken at Rockstone were not seen at Crab Falls, 
but must occur there, for they were taken farther up the stream, a fact which again 
demonstrates the necessity of exhaustive work. 

The general recommendation for future work is, then, that representative 
localities be selected twenty-five to fifty miles apart,. and that collecting be done 
exhaustively in each sort of environment to be found at each locality. A week at 
the least in each locality should be the minimum time-allowance. On a large river 
like the Amazon a month or more would be required in a favorable season to 
secure a representative collection from any one point (In an unfavorable season 
it would not be worth while to attempt fishing.) Such collecting could advan- 
tageously be supplemented by exhaustive collecting in isolated favorable units. 
Here the time requirements would be much less. 



62 memoirs of the carnegie museum 

The Ichthyological Position of British Guiana. 

In the Reports of the Princeton University Expedition to Patagonia, Vol. Ill, 
I discuss, among other things, the distribution of the fishes in the Americas south 
of the tropic of Cancer. Five distinct regions of unequal value are recognized: 
(1) Transition, (2) Mexican, (3) Brazilian, (4) Andean, and (5) Patagonian. 

In the Brazilian region the following "provinces" were enumerated: (1) Central 
America, (2) Pacific, (3) Magdalena, (4) Amazon, (5) Guiana, (6) Trinidad, (7) 16 
San Francisco, (8) Coastal, (9) La Plata, the latter divided into the Paraguay and 
Parana-La Plata. 

Concerning the Guiana Province, including French, Dutch, British, and Vene- 
zuelan Guiana, the following is said (p. 319) : 

"The Guiana Province, including one of the oldest land-masses, is drained 
by the Cachipur, Oyapoc, Cayenne, Mana, Maroni, Surinam, Corentine, Essequibo 
(Mazaruni, Cuyuni, Rupununi and other tributaries of the Essequibo), Demerara, 
Berbice, by the Orinoco and its eastern and southern tributaries, the Caroni, Caura, 
Ventuari, and by the Rio Branco, and the northern tributaries of the Amazon east 
of the Branco. 

"The feature distinguishing this region is the known or reported connection 
between neighboring streams. The Cassiquiari connects the Orinoco with the Rio 
Negro. The Atabapo is said during the rainy season to be connected with the 
Guaina, and the Rupununi of the Essequibo basin with the Tacutu of the Rio 
Branco basin. It is said that the Essequibo is also connected with the Rio Trom- 
betas through the Apini and the Oyapoc, Cachipur, and Araguary with the tribu- 
taries of the Yari, which empties into the Amazon. 

"The lower course of the Essequibo of British Guiana at least is connected 
with the lower Orinoco by natural canals, so that these form part of the Orinoco- 
Amazon-La Plata meshwork and contain the same types. The Eastern Guianas 
(French) have a less varied fauna. 

"The fauna of this region is of the greatest importance to theoretical chorology, 
since this is one of the two old land-masses, and since it was by a continuation of 
this area that South America is supposed to have been connected with Africa. 

"Our knowledge of the fish fauna of this region is derived from Muller & 
Troschel's account of the fishes of British Guiana; Bleeker's Silure de Surinam; 
Vaillant's notes on the fishes of French Guiana, and his account of the Berbice and 
the general work of Cuvier & Valenciennes, Gunther, Eigenmann & Eigenmann, 
Regan and Pellegrin. 

16 "East Brazilian Plateau," comprising 7 and S, was given a separate heading in the paper quoted. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 63 

"Unfortunately little is known of the fauna of the streams of the table land of 
Guiana, the region where the remnant of the original fauna -may be expected to 
persist. Schomburgk's collections made in those streams were largely lost. He 
states that it was rich in species (over 30). 

"Andre ('A Naturalist in the Guianas,' p. 205) says: 'In fact the falls of Para 
[of the Caura] appear to constitute an effective barrier between distinct forms of 
river life', and that the fauna above the falls is different from that below. 

"The most promising field for scientific results, if not number of species, seems 
to me to be offered by the rivers of this region, which should be explored above and 
below falls that are impassable barriers for the ascent of fishes. 

"The rivers of this region, exclusive of the northern tributaries of the Amazon, 
concerning which not much is known, contain a total of about 298 recorded species. 
Of these about 60 per cent, are also found in the Amazon; as of these about 16 
species are from the Rio Branco basin and not from the other streams and the Rio 
Branco belongs to the Amazon system, this number must be reduced by 16, which 
still leaves over 50 per cent, of the fauna identical with that of the Amazon." 

The following table is derived from the one succeeding the above quotation. 
It is condensed laterally by including the tributaries of the Branco and the rivers 
of French and Dutch Guiana in one column each, and is expanded vertically by add- 
ing the species discovered by me. 

It will especially show the relation of the fauna of the Essequibo to that of 
adjoining regions. Columns 1, 2, 5, 8, 9 and 10 offer an opportunity for a com- 
parison of the lowland faunas from west to east, i. e., of the Orinoco, Barima, 
lower Essequibo, Demerara-Mahaica, Surinam, and French Guiana. Columns 3, 4, 5, 
6 and 7 offer an opportunity for a comparison of the fauna of the Lower Essequibo 
(5) from its mouth to the Warraputa Cataracts with that of the Upper Essequibo 
and its tributary the Rupununi (4) and with that of the lower Potaro (6) and upper 
Potaro (7), and also the Rio Branco (3) with its tributaries, the Ireng, et al. The 
details of the distribution of the British Guiana species are taken up later. Those 
species found also in the Amazon are preceded by an A. Those species preceded 
by an L are also found in the La Plata system. Those peculiar to the Guianas 
are marked with an *, and the genera peculiar to the region are marked with a 
double **. The estuarine species are preceded by an M. 

In the following table column 1 represents the Orinoco basin, 2 the streams 
emptying between the Orinoco and the Essequibo, 3 the Rio Branco basin, Takutu, 
Ireng et al., 4 the upper Essequibo with the Rupununi, 5 the Essequibo below 
Warraputa, 6 the lower Potaro, 7 the upper Potaro, 8 the Demerara, 9 Dutch 
Guiana, especially Surinam, and 10 French Guiana. 



64 



MEMOIRS OF THE CARNEGIE MUSEUM 





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X 
X 


X 
X 














2. A L Potamotrygon hystrix (Midler and Henle) 


X 
X 




X 






































X 










X 
X 


















































X 
X 

X 
X 
























9. * Chamaigenes filamentosus (Cuv. and Valenciennes) 
















X 
X 
X 
X 
X 


x 






















X 












X 


12 * Aspredo sicuephorus (Cuvier and Valenciennes). . 














































X 
X 
X 




















X 


















X 
















X 












18. M Felichthys bagre (Linnaeus) 




X 


X 








X 
X 
X 


X 
X 


X 


19. M Felichthys marinus (Mitchell) 


X 










20 M Sciadeichthys flavescens (Cuv. and Valenciennes). 


































X 


22. M Sciadeichthys emphysetus (Miiller and Troschel). 
















X 
X 


X 
X 
X 




23. M Sciadeichthys proops (Cuvier and Valenciennes) . . 


















24. M Sciadeichthys luniscutis (Cuvier and Valenciennes) 

25. M Sciadeichthys albicans (Cuvier and Valenciennes) 


































X 
















X 
X 
X 
X 
X 
X 


X 
X 


Y 


















Y 


28. M Selenaspis passany (Cuvier and Valenciennes) . . . 
















V 


29. M Notarius grandicassis (Cuvier and Valenciennes) 

30. M Notarius parmocassis (Cuvier and Valenciennes) 


















































X 
X 


x 




































X 


Y 


















X 


35. M Arius spizi Agassiz ... 
















X 


X 
X 


Y 


36. M Arius fissus (Cuvier and Valenciennes). . 
















Y 




















Y 












X 


















x 
























X 
X 


X 














































Y 










X 














44. A Pseudop'unelodus raninus (Cuv. and Valenciennes) 


X 






X 


















X 
X 
X 




























































X 




X 
















X 


















X 




















X 
X 
X 




















X 














































Y 




















X 





EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



65 





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56. * Rhamdia laukidi Bleekcr 














? 




57. A Rhamdia schomburgki Bleeker 




















58. A Rhamdia seba? (Cuvier and Valenciennes) 




X 






X 








x 


59. A Rhamdia quelen (Quoy and Gaimard) 




X 




X 


X 








60. * Rhamdia holomelas (Giinther) 








X 
X 


X 






61. * Rhamdia arekaima (Schomburgk) 








X 
















X 












63. * Rhamdella foina (Muller and Troschel) 








X 


















X 






















X 
X 


X 
X 










66. * Pimelodella megalops Eigenmann 


















67. * Pimelodella ?nacturki Eigenmann! 




X 








X 






68. A L Pimelodella gracilis (Valenciennes) 


X 
X 














x 


69. A L Pimelodus clarias (Bloch) 


X 
X 




X 


X 
X 


X 

X 




X 


X 


x 


70. A L Pimelodus omatus Kner. . . 




71. * Pimelodus heteropleurus Eigenmann. 






X 
























X 






73. A Gaidiella eques (Muller and Troschel) 








X 


X 
















X 












75. A Phractocephalus hemiliopterus (Bloch and Schn.) 

76. A Brachyplaty stoma vaillanti (Cuvier and Val.) .... 

77. A L Hemisorubim platyrhynchos (Cuvier and Val.) . . . 

78. A Pseudoplaty stoma fasciatum (Linnaeus) 

79. ? A Pseudoplaty stoma tigrinum (Cuvier and Val.) .... 


X 
X 
X 

X 
X 




X 
X 


? 
X 






X 
X 






X 


x 






















X 


X 






X 
X 


? 








81. A L Sorubimichthys planiceps (Agassiz) 




























? 








X 














x 




X 


















85. * Doras hclicophilus Glinther. . . 
















X 
X 
































X 


X 


X 




X 




88. A L Doras armatus (Cuvier and Valenciennes) 

89. A Doras cataphractus (Linnaeus).. . 


X 








? 








X 


X 




X 


X 










X 
X 
































X 






















X 
X 

X 


X 






































X 




X 
X 


X 


V 


























X 


















X 










99. A L Trachelyopterus coriaceus Cuvier and Valenciennes 


















X 






X 


















X 








































X 








X 


X 




X 
X 




























X 
















X 
X 
















X 


X 










X 
X 
















X 
X 




















V 


















X 





66 



MEMOIRS OF THE CARNEGIE MUSEUM 





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111. * Auchenipterus brevior Eigeninann 












X 










112. * Tympanopleura piperatus Eigenmann. . 










X 










113. * Ageneiosus guianensis Eigenmann 














X 






114. * Ageneiosus marmoratus Eigenmann 












X 








115. * Ageneiosus inermis (Linnaeus).. . 
















X 
X 
X 
X 
X 
X 




116. * Ageneiosus armatus Lac^pede 




















117. A Ageneiosus dentatus Kner 




















118. * Ageneiosus porphyreus Cope 




















1 19. A L Ageneiosus brevifilis Cuvier and Valenciennes . . 








X 








X 




120. * Ageneiosus axillaris Gunther. . 














121. * Helogenes marmoralus Gunther. . . 










X 
X 


X 


X 


X 
X 




122. A Hupophthalmus edentatus Spix. . . 






X 




X 


V 


123. A Celopsis ceecutiens (Lichtenstein) 


X 










124. * Hemicetopsis niacilentus Eigenmann. 










X 
X 










125. * Hemicetopsis minutus Eigenmann 




















126. * Pygidium guianense Eigenmann 












X 








127. * Pygidium gracilior Eigenmann . . 












X 
X 








128. * Pygidium conradi Eigenmann. . . 




















129. ? Pygidium lamia (Kner). 16 ... 


















V 


130. * Ochmacanthus flabellijerus Eigenmann. . . 










X 












131. A Yandellia plazaii Castelnau 


X 
X 
X 
X 


















132. A L Callichthys callichthys (Linnaeus). . 




X 


X 


X 


X 


X 


X 
X 
X 
X 
X 


X 
X 
X 
X 
X 


V 


133. A L Hoplosternum littorale (Hancock). . . 


V 


134. A Hoplosternum thoracatum (Cuv. and Valenciennes) 

135. A Corydoras punctatus (Bloch) 


X 


X 


X 
X 


X 
X 






V 


X 






136. A L Plecostomus plecostomus (Linnaeus).. . 






X 
? 


V 


137. * Plecostomus hemiurus Eigenmann. 








X 


X 






13S. A Plecostomus verres (Cuvier and Valenciennes).. . . 








X 




V 


139. A Plecostomus emarginatus (Cuv. and Valenciennes) 

140. * * Lithogencs villosus Eigenmann. 




X 


X 




X 










X 
X 








141. * * Corymbophanes andersoni Eigenmann. 




















142. A L Cochliodon cochliodon (Kner).. . 


X 


















143. * Hemiancistrus schomburgki (Gunther). . 








V 

X 












144. * Hemiancistrus megacephalus (Gunther) 










X 










145. * Hemiancistrus medians (Kner).. . 














X 










X 




























X 






148. L Pseudancislrus barbatus (Cuv. and Valenciennes). 










X 






X 
X 
X 


V 


149. * Pseudancislrus depressus (Gunther). . . 


















150. * Pseudancislrus guentheri (Regan). 17 . 




















151. * Pseudancislrus nigrescens Eigenmann. . 












X 














X 
X 
X 




X 










153. F Ancistrus dolichopterus (Kner). 












X 
X 


V 








X 
X 


X 
X 
X 
X 








y 


155. A L Ancistrus hoplogenys (Gunther). 














156. A L Ancistrus cirrhosus (Valenciennes) 






X 




































X 










159. * Pseudacanthicus serratus (Cuv. and Valenciennes) 














X 
















X 


161. A Acanthicus hystrix Spix. 






X 














162. A L Loricaria calaphracta (Linnaeus) 


X 


x 


X 


X 






X 


X x 






X 


. . . . 



16 It is very doubtful whether the specimen recorded is the tmnia of Kner. 

17 British Guiana. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



67 





a 

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a 

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a 
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u 

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7 


03 

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8 


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3 

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9 


03 

c 

03 

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a 

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10 






X 










X 
X 






















1G6. * Loricariichthys microdon (Eigenmann) 








X 




















X 
X 












168. * Loricariichthys brunneus (Hancock).. . 








X 
X 


X 
X 




X 






169. A Loricariichthys platyurus (Mtiller and Troschel).. 












170. A* Loricariichthys stewarti (Eigenmann).. . 






X 










171 . A L Hemiodontichlhys acipenserinus (Kner) 








X 
X 












172. * Harttia platystoma (Giinther) 
















X 




173. A Neoplecostomus granosus (Cuv. and Valenciennes). 
















x 


174. * Farlowella hargreavesi Eigenmann 










X 
X 
X 












175. * * Bivibranchia protractila Eigenmann. . . 




















176. A Curimatopsis macrolepis Steindachner 














X 






177. A L Curimatella alburna (Mtiller and Troschel) 


X 




X 


X 
X 










17S. A Curimatus spilurus Giinther 


X 
X 


X 

X 




X 






179. * Curimatus microrcphalus Eigenmann and Eigenm. 




X 
X 
X 








ISO. * Curimatus ?norawhannce Eigenmann 
















181. * Curimatus issororoensis Eigenmann 




















182. A Curimatus kneri Steindachner 




X 












X 
X 
X 




18.3. A Curimatus cyprinoides (Linnaeus) 
















x 


184. * Curimatus schomburgki Giinther.. . 




X 












X 




185. A Curimatus ciliatus Mtiller and Troschel 






X 


X 










X 






























X 




188. A Prochilodus rubrotceniatus Schomburgk. . . 






X 
X 
X 
X 




X 


X 








189. A Prochilodus maripicru Eigenmann 














190. A Prochilodus insignis Schomburgk. . . 




















191. A Prochilodus binotatus Schomburgk. 




















192. * Prochilodus laticeps Steindachner 


X 
X 

X 


















193. A Prochilodus brama (Cuvier and Valenciennes) . . . 




















194. A Coenotropus labyrinthicus (Kner) 




X 
















195. * * Tylobronchus maculosus Eigenmann 




X 


X 
X 






X 




196. * * Chilodus punctatus Mtiller and Troschel . . . 
















197. A * Parodon bifasciatus Eigenmann. 






X 














198. A Hemiodus semiteeniatus Kner 


















X 


199. A Hemiodus immaculalus Kner. . . 


X 




















200. * Hemiodus quadrimaculatus Pellegrin 


















X 


201. * Hemiodus macukifasciata Eigenmann 












X 










202. * Anisitsia keppleri (Giinther) 
















X 
X 




203. A .4 nisitsia notata (Schomburgk). . . 










X 


X 
? 

X 




X 




204. * Piabucina unitamiata Giinther 












205. * Pyrrhulinafilamentosa Cuvier and Valenciennes. 

206. * Nannostomus beckfordi Giinther. . . 




X 




X 


X 


X 


X 
X 
X 


X 


X 


207. * Nannostomus marginatum Eigenmann 










X 










208. * Nannostomus minimus Eigenmann. . 










X 








209. * Nannostomus simplex Eigenmann 














X 
X 






210. * Poecilobrycon harrisoni Eigenmann 




















211. A Poecilobrycon trifasciatus Steindachner 










X 
X 
X 










212. * Poecilobrycon erythrurus Eigenmann 










X 
X 










213. * Pcecilobrycon ocellatus Eigenmann 








X 




X 
X 






214. ** Archicheir minutus Eigenmann. . . 












215. * Characidium laterale Eigenmann 












X 
X 
X 








216. * Characidium vintoni Eigenmann 




















217. * Characidium blennioides Eigenmann 










X 












X 




1 X 

























68 



MEMOIRS OF THE CARNEGIE MUSEUM 





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2 


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5 


6 

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u 

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is 

o 

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6 


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o 

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03 

a 
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j= 

u 
c 

u 

10 












X 
X 
X 
X 
X 
X 












220. * Characidium pteroides Eigenmann 














X 






221. * Characidium catenation Eigenmann. . . 




























X 










223. A Anostomus trimaculatus Kner 








X 










224. * Anostomus plicatus Eigenmann 








X 










225. * Anostomus orinocensis Steindachner 


X 
















226. A L Schizodon fasciatus. Spix 




X 


X 


X 


X 




X 






227. * Schizodontopsis laticeps Eigenmann 










228. A L Leporinus striatus Kner 

229. * Leporinus arcus Eigenmann 


X 


























X 
X 










230. A Leporinus nigrotoenialus (Sehomburgk). . 




X 


X 




X 










231. A Leporinus muelleri Steindachner 


X 
X 










232. A L Leporinus friderici (Bloch) 

233. A * Leporinus maculatus Mtiller and Troschel 


X 


X 
X 
X 


X 


X 
X 


X 
X 




X 


X 


V 


234. A * Leporinus granti Eigenmann. . . 














235. * Leporinus alternus Eigenmann 








X 


X 










236. A L Leporinus affinis Giinther 

237. A L Leporinus hypselonotus Giinther 

238. A L Leporinus fasciatus (Bloch) 

239. A Crenuchus spilurus Giinther 


X 
X 
X 








































X 
X 


X 






X 




X 




X 




X 




240. * * Paecilocharax bovallii Eigenmann 




X 


X 






241. * Odontostilbe melandetus Eigenmann. . . 










? 
X 
X 
X 
X 








242. * Aphyocharax melanotus Eigenmann 




















243. A * Aphyocharax erythrurus Eigenmann. . . . 






X 














244. * * Aphyodite grammica Eigenmann 
















245. A I guanodectes tenuis Cope 








X 


X 










246. A Piabucus dentatus Koelreuter 




X 


X 




X 






247. * Agoniates halecinus Mtiller and Troschel 






X 










248. * * Scissor macrocephalus Giinther 
















X 




249. A L Telragonopterus argenteus Cuvier. . . 


X 
X 




X 




X 
X 
X 








250. A L Tetragonopterus chalceus Agassiz. . . 




X 


X 


X 


X 


V 


251. A Maenkhausia oligolepis (Giinther) 




X 






252. * Mcenkhausia profunda Eigenmann 




X 










253. A Maenkhausia grandisquamis (Mtiller and Troschel) 

254. A Maenkhausia chrysarqyrea (Giinther) . 








X 

V 


X 
X 




X 

X 












x 






255. Maenkhausia ovalis (Giinther) 18 














256. * Maenkhausia browni Eigenmann. . . . 










X 


X 








257. A Mcenkhausia mega-lops Eigenmann. . . 










X 
X 
X 
X 
X 
X 
X 








258. * Maenkhausia shideleri Eigenmann. . . 










X 
X 
X 
X 
X 










259. A L Maenkhausia dichrourus (Kner). . . 


















260. A Maenkhausia lepidurus (Kner) 












X 
X 
X 
X 
X 
X 
X 
X 
X 
X 




V 


261. A Maenkhausia cotinho Eigenmann. . 












262. A Mcenkhausia colletti (Steindachner). . . 








X 
X 






263. A Mcenkhausia copei (Steindachner). . . 












264. * Pristella riddlei (Meek) 

265. * Pristella aubynei Eigenmann. . 


X 






























267. * Hemigrammus erythrozonus Durbin 


X 


X 
X 






















X 








268. * Hemigrammus rodwayi Durbin. 














269. A Hemigrammus ocellifer Steindachner. . 










X 
X 

X 










270. * Hemigrammus iota Durbin. . . 
















271. * Hemigrammus orthus Durbin. 








X 


X 
X 








272. * Hemigrammus cylindricus Durbin 















18 British Guiana. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



69 



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O 

O 

a 

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1 


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a 
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2 


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03 

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03 

u 

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3 


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3 

a 

3 

a 

3 
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4 


6 

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a 

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a 

03 

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273. * H emigrammus microplerus Meek. . . 


X 




















274. * Hyphessobrycon minor Durbin 








X 

V 












275. * Hyphessobrycon rosaceus Durbin. . . 


















276. * H i) phessobrycon riddlei Meek 










X 
X 










277. A Hyphessobrycon gracilis Reinhardt. . 



















278. * Hyphessobrycon minimus Durbin. . . 














X 




279. * Hyphessobrycon eos Durbin. . . 












X 




















X 




2S1. A Hyphessobrycon belotti (Steindaehner) 

282. ** Dermatocheir catablepta Durbin . . . 


X 
























X 

V 








283. A Creatochanes affinis Glint her 






X 


X 


X 


X 


X 
X 

X 


X 


V 


2S4. * Creatochanes melanurus (Bloch) 










285. * Creatochanes cawlomaculatus Giinther. . . 




X 






X v 






2S6. * Creagrutus melanzonus Eigenmann. . . 








X 


X 
X 
X 
X 
X 
X 






287. * Bryconarnericus hyphcsson Eigenmann. . 


















288. * Astyanax guianensis Eigenmann 










X 
X 










289. * Astyanax essequibensis Eigenmann. 


















290. * Astyanax mutator Eigenmann. . . 

















291. * Astyanax mucronatus Eigenmann . . 




















292. * Astyanax wappi (Cuvier and Valenciennes) . . 










? 
X 
X 










293. * Pwcilurichthys polylepis (Giinther). 










X 
X 
? 




X 






294. * Poecilurichthys abramoides Eigenmann . . 
















X 
X 


X 


X 


X 


X 


X 


X 


V 


296. A L Poccilurichthys abramis (Jenyns). . . 




297. * Pcecilurichthys potaroensis Eigenmann. . . 










X 










29S. * Clenobrycon spilurus (Cuvier and Valenciennes). 
299. A Ctenobrycon hauxwellianus (Cope) 














X 


X 




X 
























X 
X 
X 

x 










301. * Deuterodon pinnaius Eigenmann. . . 










X 
X 
X 
X 










302. * Phenacogister megatostictus Eigenmann. 




































304. A Holobrycon pesu (Miiller and Troschel) 










x 




X 






305. * Brycon lonqiceps Steindaehner 

306. * Brycon siebenthali Eigenmann. . . 


X 




















X 
X 












307. * Brycon jalcatus Miiller and Troschel.. . 










X 






X 




308. A * Brycon lucidus (Kner).. . 






X 










309. A Chalceus macrolepidotus Cuvier 








X 
X 


X 
X 










310. A Fowlerina orbicularis (Cuvier and Valenciennes). 

311. * Poptella longipinnis (Popta).. . . 












X 














X 




312. A L Chalcinus angulatus Spix 

313. A Chalcinus rolundatus (Schomburgk). 


X 
























X 






X 






314. A Chalcinus clonqatus Giinther 




X 














315. A Carneqiella strigata (Giinther) . 






X 


X 
X 


X 
X 




X 
X 






316. A Gasteropelecus sternicla Linnaeus. . . 




V 




X 






x 










319. F L Serrasalmo marqinalus Valenciennes 

320. A L Serrasalmo svilopleura Kner.. . 


X 
X 






X 


X 


X 




X 


















X 
X 
X 

9 

X 
X 


X 
X 












321. A * Serrasalmo rhombeus (Linnteus) 






X 


X 




X 


X 












323. A * Pygocentrus niger (Schomburgk) 






X 








1 

X 
X 








X 
? 






























327. * Pygocentrus bilineatus Eigenmann 


X 



















70 



MEMOIRS OF THE CARNEGIE MUSEUM 





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X 

X 


X 


X 
X 






X 




















330. A Mylesinus schoniburqki Cuvier and Valenciennes . 

331. A Acnodon oliqocunlhus (Miiller and Troschel) . 






























X 


X 




332. A Piaraclus macropomus (Cuvier) 

333. A Metynnis hypsauchen (Miiller and Troschel).. . 


X 


















X 


X 


X 












334. A Metynnis tnaculat-us (Kner).. . 










X 


X 


V 










X 






x 


336. A Myloplus schomburqki (Jardine) 


X 




X 
X 


X 








X 




337. A Myloplus torquatus (liner) 












338. * Myloplus kneri (Steindachner) . 
















X 




339. A Myloplus discoideus (Kner).. . 






X 














340. * Myloplus rubripinnis (Miiller and Troschel). 








X 
X 
X 


X 
X 
X 




V 






341. L * Myloplus asterias (Miiller and Troschel) 










X 






342. A Myloplus rhomboidalis (Cuvier). . 










X 


V 


343. A L Mylosoma aureum (Spix) 


X 




X 
X 














X 






X 






346. A Hydrolicus scomberoides (Cuvier) 

347. A Exodon paradoxus (Miiller and Troschel) . . 


X 
X 


















X 
X 














X 


X 












348. A Raboides affinis Giinther 

349. * Rwboid.es thurni Eigenmann 


X 


















X 














350. R Raboides microlepis (Reinhardt) 

351. A L Charax qibbosus (Gronow). . . 


X 


















X 


X 


X 


X 


X 




X 


X 




352. * Charax rupununi Eigenmann. . 






353. * * Asiphonichthys hemigrammus Eigenmann. . 








X 
X 






















X 












X 
















356. * * Acanthocharax microlepis Eigenmann. . 








X 
X 


X 






















X 








X 
















359. A Acestrorhynchus falcotus (Bloch). . . 


X 
X 


X 


X 
X 


X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 


X 
X 




X 
X 

X 


X 


V 


360. A Acestrorhynchus microlepis (Schomhurgk). 






361. A Acestrorhynchus falcirostris (Cuvier). . 








362. * Acestrorhynchus nasutus Eigenmann 
















363. A Hydrocynnus ciwieri (Agassiz) 

364. A L Hoplias malabaricus (Bloch) 


X 
X 


X 


X 
X 
X 
X 
X 
? 

X 
X 


X 
X 

X 
X 
X 
X 












X 
X 
X 
X 
X 
X 
X 
X 


X 

X 
X 

X 


X 
X 
X 
X 
X 
X 
X 


X 


X 


366. A L Hoplcrythrinus unitwniatus (Spix). 






X 
X 
X 
X 
X 


V 


367. A Erythrinus erythrinus (Bloch and Schneider) . 










X 
X 
X 


X 
X 
X 


V 


369. A L Gymnotus carapo (Linnaeus) 

370. A Sternopyqus macrurus (Bloch and Schneider) .... 


X 




X 




X 
X 






X 
X 
X 
X 
X 
X 


X 




373. A Eiqenmannia line.atus (Miiller and Troschel) 19 . . 


X 


X 


X 






374. A Steatoqenys eleqans (Steindachner). . . 














X 


X 


X 






X 










X 




X 


V 












X 
X 




V 
















379. A L Rhamphichthys marmoralus Castelnau 

380. * Sternarchorhynchusoxyrhynchus (Mull. &Trosch.) 

381. * * Stemarchogiton sachsi (Peters'! 


X 














X 










X 


V 








X 
X 
























X 






X 










X 











19 No. 373 = No. 272. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



71 





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384. * Porotergus gymnotus Ellis 










X 
X 
X 


X 
X 








385. * Sternarchus leptorhynchus Ellis. . . 


















386. A L Symbranchus marmoratus Bloch 


X 






X 






X 


v 


3S7. M Tarpon atlanticus (Cuvier and Valenciennes) .... 








X 




388. M * * Rhinosardinia serratn Eigenmann. . . 




V 














389. M A L Ilisha flavipinnis (Valenciennes) .. . 














X 
X 


X 




390. M * Odontognathus mucronatus Lac^pede 
















391. MA Pristigaster cayanus Cuvier 




















392. M A Stolephorus spinifer (Cuvier and Valenciennes). 
















X 






393. M A Stolephomts clupeoides (Swainson).. . . 
















X 




394. M * Stolephorus guianensis Eigenmann 




X 






X 
X 






X 




395. M A Stolephorus surinamensis Bleeker 












X 




396. MA Ptcrengraulis atherinoides (Linnaeus).. . 


















397. M A Lycengraulis grossidens (Cuvier) 






















39S. A Osteoglossutn bidrrhosum Agassiz. . . 






X 
X 


X 
X 


X 
X 












399. A Arapaima gigas (Cuvier) 














V 
















V 


401. A Rivuhis urophthalmus Giinther. . . 




















V 


402. A Rivuhis micropus Steindachner 




















V 


403. A Rivuhis obscurus Garman 


X 




















404. * Rivuhis breviceps Eigenmann. . . 










X 










405. * Rivuhis holmice Eigenmann 












X 








406. * Rivuhis ivaimacui Eigenmann 












X 








407. * Rivuhis stagnatus Eigenmann. . . 














X 






408. * Rivuhis lanceolatus Eigenmann. 










X 
X 










409. * Rivuhis frenatus Eigenmann 






















X 












X 
X 
X 
X 
X 
X 
X 


X 




411. A Anableps microlcpis M tiller and Troschel . . 
















412. A L Poecilia vivipera Bloch and Schneider 


X 
X 














X 


Y 


413. A Acanthophacelus reticulatus (Peters) 


X 














414. * Acanthophacelus melanzonus Eigenmann. . 
















415. * Acanthophacelus bifurcus Eigenmann. . . 




















416. * * Tomeurus gracilis Eigenmann 




X 
















417. M Tylosurus microps (Giinther). . . 














X 

X 




418. M Tylosurus almeida Quov and Gaimard 




















419. A L Potamorrhaphis guianensis (Schomburgk) 








X 


X 


X 




X 


y 






X 
? 

? 

? 

? 






421 . M Mugil brasiliensis Agassiz 


? 

? 
•> 
•> 






•? 
? 
? 

9 






X 
? 
? 
X 

X 


? 
? 

? 
? 
X 


? 


422. M Mugil cephalus Linnaeus . . 


? 


423. M Mugil incilis Hancock 


? 




? 


425. M Cynoscions acoupa Lac^pede 20 , 21 


Y 


426. M Cynoscion leiarchus (Cuvier and Valenciennes).. . 














Y 


427. M Cynoscion virescens (Cuvier and Valenciennes) 22 . . 
















X 
X 


X 




428. M Cynoscion steindachncri (Jordan). 


















429. M Cynoscion microlepidotus (Cuvier and Val.) 23 
















X 
X 
X 




430. M Macrodon ancylodon (Bloch and Schneider) 2 - 1 . . 
















X 


Y 


431. M Sagenichthys ancylodon (Bloch and Schneider)... . 
















Y 























20 Several other species of Scia?nidae may enter rivers. 

21 Lake Maracaibo. 

22 Porto Alegro, Brazil. 
83 Brazil. 

24 Panama, Rio Grande do Sul, Montevideo, West Indies. 



72 



MEMOIRS OF THE CARNEGIE MUSEUM 





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432. M Bairdiella ronchus (Cuvier and Valenciennes) 25 . . 


















X 
X 
X 




433. M Nebris microps Cuvier and Valenciennes 26 
















X 
X 
X 




434. A Plagioscion squamosissinius (Heckel) 27 . . . 


X 






X 










435. A Plagioscion auratus Castelnau 28 . . 














436. Plagioscion heterolepis (Bleeker) 
















X 
X 




437. A Plagioscion surinamensis (Bleeker) 29 . . . 




















438. M Stelliferus rastrifer Jordan. . . 
















X 
X 
X 




439. A Pachypops fwcrceus (Lacepede) 




X 




X 








X 




440. M Pachypops tri fills (Mtiller and Troschel). 












441. * Pachypops grunniens (Schomburgk). . 








X 




X 








442. ALM Micropogon furnieri (Desmarest) 30 . . . 










X 
X 
X 
X 
X 
X 
X 


X 

X 




443. M Lonchiurus lanceolata Bloch 


















444. M Centropomus undecimalis (Bloch). 


















445. M Centropomus ensiferus Poey .... 




















44fi. A C hwtobranchus flavescens Heckel. . 






X 


X 
X 


X 
X 










447. A Acaropsis nassa (Heckel). . 


X 










y 


448. * * Nannacara anomala Regan. . . 


X 




















X 








450. * /Equidens maronii (Steindaehner) 




X 










X 
X 


X 




451. A /Equidens vittata (Heckel). 


X 














452. * /Equidens polaroensis Eigenmann. . 








X 
X 
X 


X 


X 






453. A ^Equidens telramerus (Heckel).. . 






X 
X 


X 
X 


X 




Y 


454. * .Equidens geayi (Pellegrin). 






X 




V 
















456. A L Astronolus ocellatus (Agassiz). 






X 
















457. A L Mesonauta festivum Heckel 


X 
X 








X 


X 


X 


X 
X 




458. A Cichlasoma bimaculatum (Linnaeus). 




X 


X 




V 












460. A Cichlasoma scvcrum (Heckel). 








X 




X 










461. A Cichlasoma psittacum (Heckel). 


X 














462. A Acarichthys heckelii (Miiller and Troschel). 






X 


X 

X 












463. A Biotodoma cupido (Heckel) . . . 








X 




X 




















465. A Geophagus surinamensis (Bloch).. . 






X 
X 


X 


X 
X 


X 




X 

X 


X 


X 


466. A Geophagus jurupari Heckel. 




















V 


468. * Hetcrogramma ortmanni Eigenmann. 








X 

X 
X 


X 
X 
X 


X 
X 
X 










469. * Hetcrogramma steindachneri Regan. 






X 
X 




X 
X 






470. A Cichla ocellaris Bloch and Schneider. . . 


X 
X 


X 


X 


X 


471. A Cichla temensis Humboldt. 




472. A Crenicara punctulata (Gunther) 






X 

X 
? 

X 
X 
X 












473. * Batrachops punctulatus Regan. 




















474. A Batrachops semijasciatus Heckel. 


X 


















475. A Crenicichla saxaiilis (Linnaeus). 


X 










X 


X 


X 


476. * Crenicichla alta Eigenmann . 








X 
X 


X 

X 




477. A ? Crenicichla icallacei Regan. 




























X 






















X 


4S0. A Crenicichla lentieulata Heckel 


X 







































'' Maracaibo. 

26 Panama. 

27 Rios Crixas & Araguay. 

28 Rio Ucayale. 



20 Venezuela, Cauca. 

30 Havana. 

31 Guiana. 



EIGENMANN! THE FRESHWATER FISHES OF BRITISH GUIANA 



73 





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X 
X 






X 
X 










482. A Crenicichla Johanna Heckel 






X 
X 




X 






483. A Pkrophyllum scalare (Cuvier and Valenciennes). 










X 
X 
















485. * Polycentrus schomburgki Mtiller and Troschel . . . 


X 












X 












X 














X 
? 

X 










X 

? 






488. M Guavina guavina (Cuvier and Valenciennes) .... 








? 






X 












X 


X 




X 
X 






























X 








493. A Colemosus psittacus (Bloch and Schneider) 




X 






X 




X 






Totals 


89 


- nn 


85 


83 


184 


149 


22 


167 


118 


75 










Total No. of species in Essequibo Basin. 


266 





Of the four hundred and ninety-three species enumerated in the preceding list 
all but twenty-three, which are recorded from the Rio Branco only, inhabit the 
northward-flowing streams from the Orinoco on the west to the Brazilian boundary 
on the east. Of these two hundred and forty, or over 50 per cent., are also found 
in the Amazon. 

In the Rio Branco, the only stream of the Guianas flowing southward which 
has been examined, twenty-three species have been taken, aside from those which 
it has in common with the upper Essequibo. The more readily to show the relation 
of the Rio Branco to the Rupununi and upper Essequibo, the fauna of the Essequibo 
is divided into (4) the fauna of the Essequibo above the Warraputa Cataract, (5) 
the fauna below the Warraputa, (6) the fauna of the lower Potaro, (7) the fauna of 
the upper Potaro. 

From the Essequibo basin two hundred and sixty-six species have been taken, 
and this number may serve as a measure of our information, or lack of information, 
about the inhabitants of the other streams. From the large Orinoco basin but 
eighty-nine species have been recorded. 



Distribution of the Species Obtained in the Area Examined. 

The maps, given in Plates LXXI-CIII inclusive, graphically show the points 
at which the commoner species characteristic of the fauna were taken. A refer- 
ence to these maps will, I trust, be useful to the student who is interested in the 
question of distribution. 



74 MEMOIRS OF THE CARNEGIE MUSEUM 

In the following table the distribution of the species obtained is given. Species 
not obtained by me but reported by others have their approximate locality indicated 
by an asterisk. The number of specimens of each species obtained is given in 
the appropriate column under the several localities specified, thus indicating for 
each locality the relative abundance of the respective species found thereat, as 
well as the localities where each species was most numerous. For several unique 
localities the lists here given are repeated on subsequent pages. 

The columns are not quite of equal value. Under the head of Lama Stop-off 
are given all specimens obtained between Maduni Stop-off and Cane Grove Corner. 
Few came from the latter place, most of them from Lama Stop-off, which is between 
the other two. The specimens from the Georgetown trenches include those from the 
Botanic Garden. The specimens from the northwestern coast include all those 
taken in and near Morawhanna, i. e., Mora Passage, Aruka River, Koriabo Rubber 
Plantation, Issorora Plantation. The Kumaka column includes specimens from 
the Demerara River and its tributaries between Kumaka and Christianburg, a 
distance of several miles, and from some distance farther down the Demarara 
itself, at some mud-flats. The Rockstone column contains specimens from 
Rockstone itself, from the sand-bank just above Rockstone, and from a stream 
on Gluck Island across from Rockstone. The columns from Crab Falls, Tumatu- 
mari, Potaro Landing, Tukeit, Savannah Landing and Holmia contain similar 
groups of habitat. In all of these cases a radius of a mile would probably include 
all of them. I do not know how much Rupununi includes, but certainly Twoca 
Pan, and a creek opposite Massara Landing. All the specimens from this region 
were collected by Mr. Grant. Where a species was abundant in the Georgetown 
market the sign of infinity is substituted for the definite number of specimens 
preserved. 

The water of the lower Demerara (see Figure 1) and of the ocean for some 
distance out is muddy. This muddy water is inhabited by a peculiar fauna. It is 
rich in Aspredinince, Ariince, Mugil, Anableps, Scicenidce, several sharks, and a sting- 
ray. In so far as these have any relation to the strictly fresh-water fauna they 
are included in the present report. No sharp line has been or can be drawn. No 
species has been omitted which should be included, but some of the species included 
should probably be excluded. This is notably true of some of the Scicenidce, Centro- 
pi mi idee, and Mugilidce which are generally distributed in the West Indies. The 
Aspredinince, Ariince, and Anableps more clearly belong to the South American 
estuarial fauna and all properly belong here. Most of the fishes brought to the 
Georgetown market come from the estuaries or coast. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



75 



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EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



77 




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EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



79 





















































































































































































































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81 











































































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MEM01KS OF THE CARNEGIE MUSEUM 



SUMMARY OF FAMILIES. 



Dasyatidae 2 

Aspredinidae 9 

Siluridse 67 

Hypophthalmidae 1 

Helogeneidae 1 

Pygidiidae 6 

Callichthyidse 4 

Loricariidae 28 

Characidae 150 

Gymnotidae 14 

Symbranchidae 1 

Osteoglossidas 1 

Arapaimidae 1 

Elopidae 1 



Clupeidae 4 

Stolephoridae 3 

Pceciliidae 13 

Belonidae 1 

Syngnathidae 1 

Mugilida? 2 

Sciaenidae 12 

Centropomidae 2 

Cichlidae 27 



Polycentridae . . 

Gobiidae 

Soleidae 

Tetraodontidse. 



1 
4 
3 
1 
3"60 



CHAPTER V. 

ECOLOGICAL COMBINATIONS OF SPECIES. 

In many localities it was not profitable to mark the specimens separately in 
such a way that their exact locality could be retained. For instance, all species 
taken on the sand-bar at Rockstone were marked " Rockstone Sand-bar." Later it 
became evident that it might have been profitable to keep separate: (a) the species 
taken at night from a bay on the bar — they were largely big fishes; (6) those taken 
on the river side of the bar; (c) those taken in the bayou on the land side of the 
bar; (d) those taken with a large net from the lower end of the bar. Each of 
these places yielded its own fauna, but their separation must be left to someone else. 

The places of greatest interest in this connection are probably one of the 
trenches in the Botanic Garden, a woodland brook on Gluck Island, the Konawaruk 
pool, and the Warraputa, or Amatuk, Cataracts. In each of these places a single 
unit was studied exhaustively. At Amatuk, however, where the cataract furnished 
most of the specimens, a few species were obtained by seining on the sand-bar 
below the fall. From each of these units practically a complete list of species and 
the relative number of individuals of each species can be given. 

In the Botanic Garden a trench, said to have been undisturbed for twenty 
years or more, was drained and most of its contents preserved. On Gluck Island 
a short stretch of a small woodland brook was poisoned and everything but a few 
larger catfishes and cichlids preserved. At Konawaruk everything in a pool less 
than one hundred feet in diameter was killed and preserved. In the cataracts at 
Amatuk and at Warraputa the fishes were either all killed or driven out by poison, 
and everything possible secured and preserved. A list of the captures at these 
places will therefore give us the ecological composition of the various faunas. 61 In 
the following tables species not taken elsewhere are in italics. 

el These might be supplemented by the list of fishes taken at Erukin, where everything in the lower two 
hundred yards of the stream was taken, and by that at Aruataima. All but Corymbophanes, Pygidium, and 
Lithogenes of the fishes listed from Aruataima came from the small brooks. 

87 



88 



MEMOIRS OF THE CARNEGIE MUSEUM 



Species and Number of Specimens from a Trench in the Botanic 

Garden. 
It would seem from this list that the bulk of the fauna is composed of seven 
out of the twenty-three species. 



Silurim;. 

1. Rhamdia sebse 

2. Pimelodus clarias 



CALLICHTHYIDiE. 

3. Hoplosternum littorale 2 



4. Hoplosternum thoracatum . 

Loricariid.e. 

5. Plecostomus hemiurus .... 

6. Loricariichthvs brunneus. . 



1 



ChARACIDjE. 

Curimatopsis macrolepis 1 

Curimatus schomburgki 3 

Pristella riddlei 233 62 

10. Hemigrammus rodwayi 112 

11. Pceciluriehthys bimaculatus 122 



7. 
8. 
9. 



12. Ctenobryeon spilurus about 800 

13. Charax gibbosus 630 

14. Acestrorhynchus microlepis 6 

15. Hoplias malabaricus 6 

GYMNOTID.E. 

16. Gymnotus carapo 1 

17. Sternopygus macrurus ." 104 

18. Eigenmannia lineata 155 

ClCHLIDyE. 

19. Cichlasoma bimaculatum 17 

20. Mesonauta festivum 12 

21. Geophagus jurupari 1 

22. Crenicichla saxatilis 3 

PoLYCENTRIDjE. 

23. Polycentrus schomburgki 39 



Species and Number of Specimens from a Small Brook on Gluck 

Island. 



ASPREDINID.E. 

1 . Bunocephalus chamaizelus 6 

2. Agmus lyriformis 1 

SiLTJRIDjE. 

3. Rhamdia sebse 14 

4. Doras costatus 4 

5. Doras hancocki 12 

6. Doras cataphractus 20 

CALLICHTHYID.E. 

7. Hoplosternum thoracatum 74 

LORICARIID.E. 

8. Plecostomus hemiurus 1 

9. Xenocara gymnorhynchus 1 

10. Loricariichthys brunneus 24 

11. Hemiodontichthys adpenserinus .. 1 



CHARACID.E. 

12. Curimatopsis macrolepis 3 

13. Curimatus spilurus 15 

14. Chilodus punctatus 1 

15. Hemiodus maculofasciatus 1 

16. Anisitsia notatus 2 

17. Pyrrhulina filamentosa 22 

18. Nannostomus marginatus 5 

19. Poecilobrycon trifasciatus 8 

20. Pcecilobrycon erythrurus 4 

21. Pcecilobrycon ocellatus 9 

22. Characidiam pellucidum 2 

23. Leporinus nigrotseniatus 2 

24. Iguanodectes tenuis ■ 4 

25. Mcenkhausia lepidurus 8 

26. Mcenkhausia colletti 12 



62 From the Georgetown trenches only eight specimens were taken. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



89 



27. Mcenkhausia copei 11 

28. Hemigrammus ocellifer 109 

29. Hemigrammus iota 3 

30. Hemigrammus orthus 25 

31. Hemigrammus cylindricus 1 

32. Hyphessobrycon rosaceus 25 

33. Hyphessobrycon gracilis 16 

34. Creatochanes caudomaculatus . . . . 20 

35. Pcecilurichthys polylepis 10 

36. Pcecilurichthys abramoides 1 

37. Holobrycon pesu 1 

38. Chalceus macrolepidotus 5 

39. Carnegiella strigata 43 

40. Myleus rhomboidalis (young) 1 

41. Aeestrorhynchus faleatus 1 

42. Hoplias malabarieus 13 

43. Hoplerythrinus uniteniatus 1 



Belonid^;. 

45. Potamorrhaphis guianensis 3 

(Iymnotid^;. 

46. Gymnotus carapo 4 

47. Hypopomus artedi 2 

Cichlid.e. 

48. yEquidens tetramerus 4 

49. jEquidens geayi 1 

50. Mesonauta festivum 3 

51. Acarichthys heekeli 4 

52. Biotodoma eupido 6 

53. Geophagus jurupari 3 

54. Heterogramma ortmanni 3 

55. Heterogramma steindachneri 25 

56. Cichla ocellaris 2 

57. Crenicara punctulata 1 

58. Crenicichla saxatilis 2 

59. Crenicichla alta 14 

60. Crenicichla wallaeei 8 



Dasyatid^e. 
1. Potamotrygon hystrix . . 



1 



AsPREDINID.E. 

2. Bunocephalus amaurus 2 



PcECILIIDjE. 

44. Rivulus frenatus 1 

Rhamdia sebce and Crenicichla saxatilis and alta were present in larger propor- 
tion than this table indicates, many specimens being retained by the Indians. 
Only the young of the larger species were living in this brook. 

Species and Number of Specimens from the Konawaruk Pool. 

10. Loricariichthys griseus 12 

11. Harttia platystoma 4 

Characid^e. 

12. Curimatopsis macrolepis 2 

13. Curimatus spilurus 8 

14. Curimatus microcephalus 2 

15. Curimatus ciliatus 16 

16. Hemiodus maculofasciatus 7 

17. Chilodus punctatus 1 

18. Pyrrhulina filamentosa 2 

19. Characidium pteroides 3 

20. Pcecilobrycon trifasciatus 17 

21. Pcecilobrycon ocellatus 18 

22. Leporinus fasciatus 1 

23. Odontostilbe melandetus 3 

24. Aphyodite grammica 3 

25. Iguanodectes tenuis 10 



Silurim:. 

3. Leptoglanis essequibensis . 

4. Chasmocranus longior . . . 

5. Pimelodella cristata 



1 

... 2 

.... 2 

6. Hemidoras leporhinus 3 

PYGIDIID-ffi. 

7. Ochmacanthus flabelliferus 3 

Callichthyid;e. 

8. Corydoras punctatus 16 

LORICARITD^E. 

9. Lithoxus lithoides 7 



90 



MEMOIRS OF THE CARNEGIE MUSEUM 



26. Mcenkhausia chrysargyreus 15 

27. Mcenkhausia dichrourus 12 

28. Mcenkhausia lepidurus 22 

29. Mcenkhausia colletti 19 

30. Hemigrammus ocellifer 3 

31. Hyphessobrycon minor 3 

32. Creatochanes affinis 1 

33. Deuterodon pinnatus 2 

34. Phenacogaster microstictus 7 

35. Chalceus macrolepidotus 5 

36. Fowlerina orbicularis 72 

37. Catoprion mento 3 

38. Myloplus rhomboidalis 1 

39. Charax gibbosus 2 

40. Acestrorhynchus falcatus 1 

41. Acestrorhynchus microlepis 5 

42. Acestrorhynchus falcirostris 2 



Gymnotid^e. 

43. Sternopygus raacrurus 2 

44. Porotergus gymnotus 1 

Belonid^:. 

45. Potamorrhaphis guianensis 5 

Cichlid^e. 

46. jEquidens geayi 1 

47. /Equidens potaroensis 1 

48. Crenicichla alta 5 

49. Crenicichla wallacei 11 

50. Mesonauta festivum 7 

51. Geophagus jurupari 7 

52. Biotodoma cupido 13 

53. Heterogramma ortmanni 11 

Gobiid^e. 

54. Dormitator gymnocephalus. 



Species and Number of Specimens from the Warraputa Cataract. 

As stated before, the specimens taken at this place all came from a small 
branch of the cataract where the water wound its way about and under rocks. 
The fishes were driven from their hiding-places by poison. 



Siltjrim:. 

1. Brachyglanis melas 2 

2. Leptoglanis essequibensis 5 

3. Chasmocranus longior 12 

4. Rhamdella foina 5 

Loricariid^e. 

5. Hemiancistrus megacephalus 1 

6. Pseudancistrus barbatus 6 

7. Lithoxus lithoides 72 

8. Harttia platystoma 20 

ChARACIDjE. 

9. Curimatus ciliatus 2 

10. Characidium catenatum 1 

1 1 . Iguanodectes tenuis 6 

12. Mcenkhausia chrysargyreus 1 

13. Mcenkhausia dichrourus 2 

14. Mcenkhausia lepidurus 7 



15. Creatochanes affinis 1 

16. Creagrutus melanzonus 2 

17. Astyanax guianensis 3 

18. Deuterodon pinnatus 19 

19. Holobrycon pesu 1 

20. Fowlerina orbicularis 7 

21. Myloplus pacu 15 

22. Myloplus rhomboidalis 7 

Gymnotid,e. 

23. Sternopygus macrurus 3 

24. Eigenmannia virescens 4 

25. Sternarchorhynchus oxyrhynchus 1 

26. Sternarchus leptorhynchus 1 



ClCHLTD^E. 

27. Geophagus jurupari. . . 

28. Cichla ocellaris 

29. Crenicichla lugubris . . . 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



91 



Species and Number of Specimens from the Amatuk Cataract. 



SlLURTD^E. 

1. Brachyglanis frcnata 3 

2. Brachyglanis phalacra 1 

3. Myoglanis potaroensis 8 

4. Chasmocranus longior 13 



5. Chasmocranus brevior . 

Pygidiid^e. 

6. Hemic.etopsis minutus . . 

7. Pygidium conradi 



LoRICARIID^E. 

8. Plecostomus hemiurus 

9. Hemiancistrus megacephalus . 
10. Pseudancistrus nigrescens . . . . 



1 

1 
1 

4 
9 
2 

11. Lithoxus lithoides. . ... 87 

Characid^e. 

12. Curimatus microcephalus 8 

13. Hemiodus pellegrini 3 

14. Characidium laterale 

15. Characidium blennioides 13 

16. Nannostomus minimus 1 

17. Pcecilobrycon erythrurus 1 

18. Anostomus anostomus 2 

19. Anostomus plicatus 2 

20. Leporinus arcus 2 

21. Leporinus megalepis 12 



22. Mcenkhausia browni 2 

23. Mcenkhausia colletti 

24. Creatochanes affinis 1 

25. Pcecilurichthys abramoides 48 

26. Pcecilurichthys potaroensis 13 

27. Dcuterodon pinnatus 67 

28. Deuterodon potaroensis 6 

29. Phenacogaster megalostictus 4 

30. Fowlerina orbicularis 7 

31. Myloplus rhomboidalis 8 

32. Acestrorhynchus falcatus 3 

33. Hoplias malabaricus 12 

GYMNOTIDiE. 

34. Sternopygus macrurus 9 

35. Sternarchorhynchus oxyrhynchus 4 

36. Sternarchus gymnotus 3 

37. Sternarchus leptorhynchus 2 



Pceciliim:. 
38. Rivulus waimacui 



1 



ClCHLID.E. 

39. jEquidens geayi 8 

40. iEquidens potaroensis 17 

41. Crenicichla alta 8 

42. Crenicichla lugubris 1 



Species of the Coastal Streams not taken in any of the Inland 

Stations or not beyond Wismar and Rockstone. 

Those species extending as far as Rockstone or Wismar are in italics, those near 

the coast or in brackish water are marked with an *. The Ariince are not considered 

in this list. 

SiltjridjE. Loricariid.e. 

1. Pimelodella macturki. 7. Plecostomus watwata. 

2. Hemidoras micropenis. 8. Plecostomus plecostomus. 

3. Trachycorystcs galeatus. 

4. Pseudauchenipterus cceruleus. 

5. Ageneiosus brevifilis. 



Callichthyid^;. 
6. Hoplosternum littorale. 



Characid.e. 
9. Curimatus schomburgki. 

10. Curimatus morawharmse. 

11. Curimatus issororoensis. 

12. Piabucus dentatus. 



92 



MEMOIRS OF THE CARNEGIE MUSEUM 



13. Pristella riddlei. 

14. Pristella aubynei. 

15. Hemigrammus unilineatus. 

16. Hemigrammus rodwayi. 

17. Hyphessobrycon minimus. 

18. Ctenobrycon spilurus. 

19. Chalcinus elongatus. 

20. Pygocentrus bimaculatus. 

Clupeid^e. 
21.*Rhinosardinia serrata. 

Stolephorid^e. 
22.*Stolephorus guianensis. 



Pceciliid^:. 
23.*Poecilia vivipara. 
24. Acanthophacelus melanzonus. 
25.*Acanthophacelus reticulatus. 
26. Tomeurus gracilis. 

Doryrhamphid.e. 
27.*Dorj - rhamphus lineatus. 

CICHLID.E. 

28. Nannocara anomala. 

29. Mquidens moroni. 

Gobiid^e. 
30.*Eleotris amblyopsis. 
31.*Evorthodus breviceps. 



A few of these species, like Ageneiosus brevifilis, are not limited to this area, 
but as no specimens were captured in the interior they are included in this list. 

List of Species not taken at Rockstone, Wismar, or lower down 
in the essequibo and demerara rlvers. 

While the downward limit of many of these species has not been determined 
it seems certain that they are excluded from the coastal regions. Sixteen species 
marked with an * extend as far down as Crab Falls. The large number (eighty-two 
species) not found at Rockstone shows that the fauna of the upper courses of the 
river is much richer in exclusives than the coastal region with its thirty-one peculiar 
forms. 



SlLURIDjE. 

1. Megalonema megacephalum. 

2. Microglanis poecilus. 

3. Pseudopimelodus albomarginatus. 

4. Braehyglanis frenata. 

5. Braehyglanis phalacra. 
6.*Leptoglanis essequibensis. 

7. Myoglanis potaroensis. 

8. Chasmocranus longior. 

9. Chasmocranus brevior. 

10. Rhamdia quelen. 

11. Rhamdella foina. 
12.*Pimelodclla megalops. 

13. Pimelodus heteropleurus. 

14. Oxydoras niger. 
15.*Hemidoras notospilus. 



16. Hemidoras leporhinus. 

17. Auchenipterus brevior. 
18.*Tympanopleura piperata. 

Pygidiuxe. 

19. Hemicetopsis macilentus. 

20. Hemicetopsis minutus. 

21. Pygidium guianense. 

22. Pygidium conradi. 

23. Pygidium gracilior. 

24. Ochmacanthus flabelliferus. 

Loricariid^e. 

25. Lithogenes villosus. 

26. Corymbophanes andersoni. 

27. Hemiancistrus megacephalus. 

28. Pseudancistrus nigrescens. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



93 



29. Ancistrus temmincki. 
30.*Ancistrus lithurgicus. 
31.*Lithoxus lithoides. 

32. Loricariichthys microdon. 

33. Loricariichthys platyurus. 

ChARACIDjE. 

34. Curimatella alburnus. 
35.*Hemiodus C[uadrimaculatus. 

36. Characidium laterale. 

37. Characidium vintoni. 
38.*Characidium blennioides. 
39. Nannostomus minimus. 
40.*Anostomus anostomus. 
41. Schizodon fasciatus. 
42.*Schizodontopsis laticeps. 

43. Leporinus arcus. 

44. Leporinus granti. 

45. Pcecilocharax bovallii. 

46. Odontostilbe melandetus. 

47. Aphyodite grammica. 

48. Tetragonopterus argenteus. 

49. Mcenkhausia oligolepis. 

50. Mcenkhausia browni. 
51.*Mcenkhausia dichrourus. 

52. Hemigrammus erythrozonus. 

53. Hyphessobrycon minor. 

54. Hyphessobrycon eos. 

55. Dermatocheir catablepta. 
56.*Creagrutus melanzonus. 

57. Bryconamericus hyphesson. 

58. Pcecilurichthys potaroensis. 

59. Astyanax mucronatus. 

60. Astyanax mutator. 



61. Deuterodon pinnatus. 

62. Deuterodon potaroensis. 

63. Pygocentrus piraya. 

64. Exodon paradoxus. 

65. Charax rupununi. 

66. Gymnorhamphichthys hypostomus. 

Gymnotid.e. 

67. Sternarchorhynchus oxyrhynchus. 

68. Porotergus gymnotus. 

69. Sternarchus leptorhynchus. 

70. Sternarchus albifrons. 

OsTEOGLOSSID.«E. 

71.*Osteoglossum bicirrhosum. 

Pceciliid^e. 

72. Rivulus breviceps. 

73. Rivulus holmise. 

74. Rivulus waimacui. 

Sclenim:. 

75. Pachyurus schomburgkii. 
76.*Pachypops grunniens. 

Cichlid.e. 
77. Nannocara bimaculatum. 
78.*^Equidens potaroensis. 
79. Cichlasoma severum. 
80.*Batrachops punctulatum. 

Gobiid^;. 

81. Dormitator gymnocephalus. 

Soleid.e. 

82. Soleonasis finis. 



CHAPTER VI. 

THE ICHTHYIC FAUNA OF THE POTARO RIVER AND OF THE GUIANA PLATEAU. 

The Guiana Highland has a double interest. First, it is presumably one 
of the oldest land-masses of South America, probably dating back to the time 
when Africa and South America were connected by land or by a chain of islands. 
Second, all of the rivers, so far as known, descend from the plateau over falls which 
no fish can ascend, the most prominent of these being the Kaieteur, with a height 
of seven hundred and forty-one feet, which divides the Potaro into an upper and 
a lower course. 

Measurements made by Brown show that the Potaro, six hundred feet above 
the fall, is four hundred and two feet wide and twenty and two-tenths feet deep. At 
the brink of the fall it is three hundred and sixty-nine feet wide. These measurements 
are taken at flood. The fall is seven hundred and forty-one feet high and in the 
one thousand and twenty feet down stream from the kettle below the fall the 
Potaro has a fall of eighty-one feet. The brink of the fall is about eleven hundred 
and thirty feet above sea-level. 

The map of Anderson makes the Potaro about thirty miles long to Amatuk, 
fifteen from Amatuk to the Kaieteur and fifteen from the Kaieteur to Holmia, meas- 
ured in straight lines; it is twice as long or more following the course of the stream. 

The lower Potaro River, from the Kaieteur to near Potaro Landing, follows a 
northwest to a northeast course, but from Potaro Landing to its mouth the course 
is from west to east. 

At Tumatumari a dike of diabase five hundred yards wide crosses the Potaro 
and causes the cataract at that point. Various dikes cross the Potaro between 
Tumatumari and a point two miles above Potaro Landing, but none of these inter- 
fere with navigation by launches. 

Above the mouth of the Curiebrong, 63 a northern tributary of the Potaro, there 
are a series of dikes causing the Ichaura Rapids, and the Cobenatuk and Pakatuk 
Cataracts. 

63 The Curiebrong River, a northern tributary of the Potaro, comes down from the table-land in the Amaila 

fall, one hundred and forty-four feet high, and then down an inclined plane for two miles to the level of the 

river below. 

94 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 95 

Between the Pakatuk Cataract and Amatuk the river is again navigable for 
small boats. The "Amatuk Falls are over some of the lower beds of the great 
sandstone and conglomerate formation. Here the sandstone and conglomerate is 
fine grained, with occasional quartz-pebbles, of a red color, and shows very clearly, 
and in many places markedly, current-bedding. Not more than about twenty-five 
feet of the lower beds are exposed in the actual section of the falls. A sill of diabase 
intrusive through the sandstone causes small rapids above the main fall." 

At Waratuk (a few miles above Amatuk) a dike of diabase causes rapids, and as 
stated, another series of cataracts occurs at Tukeit and between Tukeit and the 
foot of the Kaieteur. 

Above the Kaieteur, for about forty miles as the river flows, the Potaro is 
navigable to bateaus without interruption. At Aruataima at the end of this stretch 
is another cataract and beyond this point I did not go. 

As stated, one of the chief objects of the expedition was to stud}' the relation 
of the faunas of the upper to that of the lower Potaro. 

The questions of prime importance concerning the fauna of the upper Potaro, 
i. e., the Guiana Plateau, are: 

1. Of what does it consist? 

2. Whence did it come? 

3. How did it get there? 

The first and second of these questions are simplified as to fishes by the obvious 
fact that fishes live in water, and that most of them die in a few moments after 
being taken from the water. Their migrations must be along waterways; i. e., 
along well-defined and restricted channels. 

1. Fishes Taken in the Potaro. 
The species found both above and below the Kaieteur are given in italics. 
Those confined to the plateau are in heavy-faced type. These two categories 
answer specifically the first of the above questions. Species peculiar to the Potaro 
are marked with an asterisk, those genera peculiar to it with a double asterisk. 
Those found between the mouth and the cataracts above Potaro Landing are 
marked A, those between the latter place and Amatuk, B, and those above the 
Amatuk Cataract, C. 

Aspredinid.-e. 3. Pseudopimelodus villosus A 

1. Bunocephalus chamaizelus A B 4.*Pseudopimelodus albomarginatus C 

Silurid^e. 5.*Brachyglanis frenata B 

Pimelodince. 6.*Brachyglanis phalacra B 

2.**Megaloaeraa platycephalum A 7.*Myoglaiiis potaroensis ABC 



96 



MEMOIRS OF THE CARNEGIE MUSEUM 



8. Chasmocranus longior A B 
9.*Chasmocranus brevior A B 

10. Rhamdia quelen A (B? C?) 

1 1 . Pimelodella cristata A 

12. Pimelodella megalops A 

13. Pimelodus clarias A 

14. Pimelodus ornatus A 

15. Doras hancocki A 

DoradincB. 

16. Doras cataphractus (A?) B 

17. Leptodoras linnelli A 

18. Hemidoras carinatus A 

19. Hemidoras leporhinus A 

Auchenipterinas. 

20. Centromochlus aulopygius A 
21.*Auchenipterus brevior A 
22.*Ageneiosus marmoratus A 

Helogeneid^e. 
22>.*Helogenes marmoraius C 

PyGIDIIDjE. 

Cetops ince. 
24.*Hemicetopsis maciientus A 
25.*Hemicetopsis minutus B 

Pygidiince. 
26.*Pygidium conradi B C 
27.*Pygidium gracilior B 
28.*Pygidium guianensis 

CallichthyidjE. 

29. Callichthys callichthys (A B C?) 

30. Corydoras punctatus A B 

LORICARIID/E. 

Plecostomince. 
31.**Lithogenes villosus 
32. Plecostomus hemiurus (A?) B C 
33.**Corymbophanes andersoni 
34. Hemiancistrus megacephalus B C 
35.*Pseudancistrus nigrescens 
36.*Lithoxus lithoides (A?) B C 

Loricariince. 
37. Loricariichthys brumieus A 



38. Loricariichthys platyurus A 

Characid^e. 
Curimatinm. 

39. Curimatus spilurus A (B?) C 

40. Curimatus microcephalus ABC 

Prochilodinm. 

41. Prochilodus rubrotseniatus A 

Hemiodince. 

42. Hemiodus quadrimaculatus ABC 

43. Anisitsia notata A 

Chilodince. 

44. Tylobronchus maculosus A B 

Nannostomatince. 
45.*Characidium laterale (A?) B 
46.*Characidium vintoni C 
47. Characidium blennioides ABC 
48.*Nannostomus minimus B 

49. Pcecilobrycon erythrurus B 

50. Pcecilobrycon ocellatus A 

Anostomirue. 

51. Anostomus anostomus A B 

52. Anostomus plicatus A B 

53. Schizodon fasciatus A 

Leporinince. 
54.*Leporinus arcus ABC 

55. Leporinus nigrotsniatus A 

56. Leporinus friderici A B 

57. Leporinus maculatus ABC 

58. Leporinus alternus A (B?) C 

59. Leporinus fasciatus A 

Pyrrhulinince. 

60. Pyrrhulina filamentosa (A? B C) 

Crenuchince. 
Ql**Poecilocharax bovallU C 

Iguanodectince. 
62. Iguanodectes tenuis A 

Tetragonopterince. 
63.*Tetragonopterus argenteus A 
64. Tetragonopterus calceus B 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUTANA 



97 



§5* Mcenkhausia oligolcpis A B (C?) 

66. Mcenkhausia grandisquamis A B 

67. Mcenkhausia chrysargyrea A 
(j8*Mcenkhausia browni ABC 

69. Mcenkhausia shideleri A 

70. Mcenkhausia lepidurus A B 

71. Mcenkhausia cotinho ABC 

72. Moenkhausia colletti A B 
73.*Hemigrammus erythrozonus B 

74. Hemigrammus orthus (A B?) C 

75. Hemigrammus cylindricus A 

76. Hyphessobrycon eos B C 
77.*Dermatocheir catablepta A 

78. Creatochanes affinis ABC 

79. Creatochanes caudomaeulatus A 

80. Creagrutus melanzonus A 
81.*Bryeonamericus hyphesson A 

82. Pcecilurichthys polylepis A 

83. Pcecilurichthys bimaculalus (A B C?) 

84. Pcecilurichthys abramoides A B 

85. Pcecilurichthys potaroensis B C 

86. Astyanax mucronatus A (B?) C 

87. Astyanax essequibensis A 

88. Astyanax guianensis A 
89.*Astyanax mutator 

90. Deuterodon pinnatus (A?) B C 
91.*Deuterodon potaroensis A B 

92. Phenacogaster microstictus A 

93. Phenacogaster megalostictus ABC 

Bryconince. 

94. Holobrycon pesu A 

95. Brycon falcatus (A B?) C 

Chalcininm. 

96. Chalceus macrolepidotus A 

Brachycalcinince. 

97. Fowlerina orbicularis A B 

Gasteropelicince. 

98. Carnegiella strigata A 

99. Gasteropelicus sternicla (A B C?) 

SerrasalmiruE. 
100. Serrasalmo gymnogenys A 



101. Serrasalmo rhombeus A 

Mylince. 

102. Myloplus rubripinnis A 

103. Myloplus rhomboidalis A B 

104. Myleus pacu A 

Characince. 

105. Charax gibbosus A 

106. Cynopotamus essequibensis A 

107. Acanthocharax microlepis A 

A ceslrorhynchince. 

108. Acestrorhynchus falcatus ABC 

109. Acestrorhynchus microlepis A B 

Erythrinince. 

110. Hoplias macrophthalmus A (B?) C 

111. Hoplias malabaricus ABC 

112. Hoplcrythrinus unitceniatus (A B C?) 

113. Erythrinus erythrinus A (B?) C 

GYMNOTIDiE. 

Electrophorince. 

114. Electrophorus electricus A 

Gymnotince. 

115. Gymnotus carapo (A B?) C 

Hijpopomince. 

116. Sternopygus macrurus ABC 

117. Hypopomus brcvirostris (A B C?) 

118. Eigenmannia macrops A 

119. Eigenmannia virescens A B 

120. Rhamphichthys rostratus A 

121. Gymnorhamphichthys hypostomus A. 

Stemarchince. 

122. Sternarchorhynchus oxyrhynchus (A?) B 

123. Porotergus gymnotus B 

124. Sternarchus leptorhynchus B 

125. Sternarchus albifrons A 

PCECILIID.E. 

126.*Rivulus breviceps C 
127.*Rivulus waimacui B C 
128.*Rivulus holmiae 

BELONIDjE. 

129. Potamorrhaphis guianensis A 



98 MEMOIRS OF THE CARNEGIE MUSEUM 

Sclenid^e. 138. Heterogramma steindachneri A 

130. Pachyurus schornburgki A 139. Cichla ocellaris A 

Cichlimi 140. Crenicichla alta ABC 

131. Nannocara bimaculata B 14L Crenicichla wallacei A 
132.*iEquidens geayi A B 142 - Crenicichla lugubris ABC 

133. Mquidens potaroensis ABC 143 - Crenicichla Johanna A 

134. Cichlasoma severum B Soleidjs. 

135. Geophagus surinamensis A 144. Achiurus lineatus A 

136. Biotodoma cupido A 145.**Seleonasus finis A 

137. Heterogramma ortmanni (A?) B (C?) 

Of these, Poecilurichthys bimaculatus, Hypopomus brevirostris, and Callichthys 
callichthys have not been taken in the Potaro below the Kaieteur, but, inasmuch 
as they are found on the plateau and in the Essequibo, they probably also occur in 
the lower Potaro, and are so rated. 

The table on page 99 summarizes the different categories in the preceding list. 

In this table the first column represents the species found below the Kaieteur, 
and it will be seen that while there are one hundred and forty species found in this 
part of the river, there are but twenty-three above the Kaieteur. 

It is, however, not fair to compare the fauna of the plateau with the fauna 
of the entire lower Potaro, because the fishes of the Essequibo can easily ascend to 
Tumatumari. The cataract at Tumatumari is probably not an effective barrier 
to many fishes. There is a more difficult series of cataracts between Potaro Landing 
and Kangaruma, and another cataract at Amatuk. The cataract at Waratuk, like 
that of Tumatumari, may be left out of account. Hy comparing the fauna as 
determined in the three lower divisions of the Potaro it is seen that only seventy- 
six species (B and C) are found above Kangaruma. The rest, with very few excep- 
tions, are fishes of the lower and middle Essequibo. Evidently species that are 
not able to ascend the Potaro Landing cataracts need not be expected on the plateau. 

By further restricting the vision we find that only thirty-six species have so 
far been taken above the Amatuk Cataract. This is certainly not all of the species 
found in this area, but the number indicates that there is a distinct reduction in the 
number of species as compared with the Potaro at Tumatumari. 

Further investigations should be made of the fauna of the Potaro above the 
Amatuk cataract and above the Kaieteur. Eight species found above the Kaieteur 
and in the Essequibo, but not taken in C, should probably be added to the thirty-six 
actually captured. It would seem from these lists that the groups extending to 
the base of the Kaieteur, but not found above it, are the Curimatinse, Hemiodinse, 
Nannostomatinae, Leporininae, Bryconinse, Gasteropelicinse and Acestrorhynchinse. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



99 



Aspredinidae 

Siluridae: 

Pimelodinae 

Doradinae 

Auchenipterinae . . 

Ageneiosinae 

Helogeneidae 

Pygidiidae: 

Cetopsinae 

Pygidiinae 

Callichthyidae 

Loricariidae: 

Plecostominae 

Loricariinae 

Characidae: 

CurimatinsB 

Prochilodina? 

Hemiodinae 

Chilodinae 

Nannostomatinae 

Anostomatime. . . 

Leporinae 

Pyrrhulininse . . . . 

Crenuchinae 

Iguanodectinae . . . 

Tetragonopterina? 

Brycoiiina? 

Chalcinina? 

Brachycalcininse . . 

Gasteropelicinae . . 

Serrasalminae . . . . 

Mylina? 

Characinae 

Acestrorhynchinae 

Erythrininae 

Gymnotidae: 

Electrophorinffi. . . 

Sternarchinae . . . . 

Hypopominae . . . . 

Gymnotinae 

Poeciliidae 

Belonidae 

SciaDnidae 

Cichlidae 

Achiridas 



Species Below the 


A 


B 


c 


Species Above the 


Kaieteur. 








Kaieteur. 


1 


1 


1 








13 


10 


5(6?) 


2(3?) 


1 


o 


4(5?) 


1 








2 














1 














1 





1 


1 


1 


2 


1 


1 








2 





2 


1 


1 


2 


1 


1 





1 


4 


(2?) 


4 


3 


2 


2 














2 


2 


1(2?) 


2 





1 


1 











2 


2 


1 


1 





1 


1 


1 








6 


2(3?) 


5 


1 





3 


3 


2 








6 


6 


3 (or 4?) 


3 





1 


(1?) 


1 


1 


1 


1 








1 


1 


1 


1 











30 


23(26?) 


12(15?) 


9(11?) 


5 


2 


1(2?) 


0(1?) 


1 





1 














1 


1 











2 


1(2?) 


(1?) 


(1?) 





2 














3 


1 











3 














2 


2 


2 


1 





4 


3(4?) 


1(4?) 


2(4?) 


3 


1 














4 


1(2?) 


3 








6 


5(6?) 


2(3?) 


1(2?) 


2 


1 


(1?) 


(1?) 


1 


1 


2 





1 


2 


1 


1 


1 











1 


1 











13 


10(11?) 


7 


3(4?) 


3 


2 


2 












140 



87(102?) 58(71?) | 36(44?) 



23 



2. Whence did the fauna of the plateau come? 

A. Is it the nucleus of the original fauna of Guiana? Or 

B. Have the faunas on the plateau and the lowland developed from a 

common nucleus? Or 

C. Is it a relict of a more abundant modern fauna? Or 

D. Does it consist of recent immigrants? Or 

E. Is it a mixture? 

To assist in answering these questions I give the species of the plateau with 
their distribution in the Potaro and also their general distribution in South America. 



100 



MEMOIRS OF THE CARNEGIE MUSEUM 





s 

e3 
<D 
U 

+3 

CO 

<a 

CO 

'1 

CO 
05 
O 

O 


c3 

03 
u 

I 

Q 


6 
.a 

'3 
a 

a 

to 

H 


03 

8 

3 
a 

a 

3 
H 


u 
c 
■5 
a 

03 

o 
a 
o 

Ph 


03 

a 

3 
u 
a 

M> 

a 

05 


a 

5 

H 


3 

3 
-^ 
03 

B 


3 

3 
03 


"53 

3 

H 


si 
c 
^3 
a 

eS 

J= 
03 

a 
a 

oj 

> 

03 


03 

| 

M 


si 

S 
3 
"5 
3 

1 


3 

h 

'a, 

03 
% 





a 

O 


d 


u 

03 

a. 
03 

1 


c 


3 


03 
03 

s 

03 
Hi 


6 

CO 

'3 

3 
03 

a 

03 
03 












1 

X 














13 

19 

1 


41 
15 




3 


8 


X 


X 




2. Helogenes marmoratus 




? 














14 
































15 


7 


















in 






1 


1 


X 


X 


























1 

1 

35 






6. Corymbophanes andersoni. . . 






































7. Pyrrhulina filamentosa 


365 


95 


40 








2 






7 

63 

7 

9 

27 


50 

220 

41 


104 

3 

41 


14 






x 


























9. Mcenkhausia oligolepis 








8 

1 

47 


1 




3 








1 






X 


? 












2 
6 




69 38 1 












6 


4 


5 






8 


45| 9 
5 


30 

1 






x 




12. Poecilurichthys bimaculatus. . 


233 






X 


X 


V 






















121 
4 
2 












14. Hoplias malabaricus 

15. Hoplerythrinus uiiita3niatus. . 


72 
15 


7 

4 
12 

1 
35 


18 

8 

15 

11 
1 
5 




1 






12 


1 




9 

S 


2 
10 

9 
15 




3 


1 

16 

32 

4 


X 
X 
X 
X 
X 
X 


X 
X 

X 
X 
X 


X 


16. Ervthrinus erythrinus 




2 










10 
30 


3 37 
... 34 








12 

4 

181 










1 


1 
2 

5 


V 


18. Hypopomus brevirostris 














?, 






18a. Eigenmannia virescens 




2 


1 










1 






3 


V 


19. Rivulus holmise 










18 

33 

1 

9 








2 
16 
35 




1 


4 
1 


3 

46 

2 


17 


1 


25 


27 


5 






















X 
9 










2 






4 


2 


8 











The numbers in the respective squares show the number of specimens taken 
and thus indicate the relative abundance of the species at each place. 
An analysis of this list shows three groups of species. 

a. Very widely distributed species: 1, 4, 7, 9, 11, 12, 14, 15, 16, 17, 18, 21.- 
All of these are found in the neighboring river Ireng, of the Amazon basin. All of 
these are also found below the Kaieteur, but in different proportions. The per- 
centage of the total fauna of the plateau formed by this group is 56.60. 

b. Peculiar species of very widely distributed genera. 

(1) Confined to the plateau: 3, 13, 19 = 13.01 per cent. 

(2) Found also below the Kaieteur: 10, 20, 22 = 13.01 per cent. 

c. Peculiar genera and species. 

(1) Peculiar to the plateau: 5, 6 = 8.69 per cent. 

(2) Found both above and below the Kaieteur, but confined to the Potaro 
(?):2, 8 = 8.69 per cent. 

A. If this fauna is the nucleus of the original undifferentiated fauna of South 
America we are at once confronted by the fact that 56.60 per cent, of the species 
are identical with species now found everywhere, and 26.02 per cent, consist of 
species belonging to genera of the widest distribution in South America. The 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



101 



1 


5 

id 

in 
j> 
Id 


■ ■— 

p c 
E- 1 

u p 

"1 


+2 

re 


o 

5 „ 
E "5 


8 

5_ 

3 


c 
in 

■ 

a- 

c 




Rhamdia auelen 
Helogjenes marmoratus 




__7J 


a l 








C(2)2 


y^ auiancnse 




bd)3 


CaflicMtya caflicfillwa 

Lithogenes viliosuS 


H 


? 


? 


a 4 










C(0 5 


CorymbophaneS andersom 
FyrrDulina plsmentoaa 
PoecWobrycon Dovallii 








Co)6 
a 7 
c{2)8 


HH 










ManktauSi'a oligolepis 
Moenkhausia brown! 






a 9 




b(i)10 


Creatocnanes af finis 
Astyanax bimaculaTua 
/^styanax mutator 
Hoplias maiaDancus 
Hop1ery1nrinU3 unitaeniaujs 
Erythrmus eryfhnnus 
Gymnotus carapo 
Hypopomus brevirobtriS 












a n 


? 


9 


<? 


a l? 












fed) 13 








a h 








HB^ ? 


7 


7 


B 15 




? 




a 16 




7 1 


a \7 


pHQ ? 


7 1 


a 18 


Rivutus nolmtaz 












boil 9 
b(2)20 


>EauidenS poferoensis 






HeTerogramma ortmanni 
Crtn'iocMa alfa 


■i_^ 


| ? ^ 


a si 


^4— 








1 W)22 


i 











Fig. 23. Table showing Distribution of the Fishes taken by C. H. Eigenmann in the Potaro River above 
the Kaieteur Falls. (No. 18a, mentioned in the table above, should have been added. It was overlooked 
in preparing this figure.) 

great improbability that so many species should have retained their identity since 
the early tertiary, or should have diverged only in minor specific characters, dis- 
poses of the theory that this fauna as a whole is the nucleus of the original South 
American fauna. The number of species peculiar to the plateau forms a larger 
percentage than a corresponding list for the entire Potaro below the Kaieteur, but 
not too large to be readily accounted for by the easy access to the Lower Potaro pos- 
sessed by all the species of the Essequibo. Such easy access tends to lower the per- 
centage of uniques. 

The percentage of peculiar species above the Potaro Landing is about the same 
as for the plateau, and in actual numbers almost equal to the entire fauna of the 
plateau. 



102 MEMOIRS OP THE CARNEGIE MUSEUM 

B. The same facts also dispose of the notion that this fauna as a whole may 
have developed concomitantly with the lowland fauna from a common nucleus. If 
it had so developed, we could not expect so large a percentage to be identical. 

C. Is this poverty-stricken fauna the relict of a more abundant and divergent 
fauna, dating from a time when the plateau may have been easily accessible to the 
present diverse fauna of the lowland? 

If it is such a relict the fact implies: 

(a) That at some time in the past, when the plateau was more easily acces- 
sible than now, in fact formed part of the general level, it shared the fauna of the 
region with the general level. 

(6) That the fauna became isolated by the gradual elevation and formation 
of the plateau, and of the falls in its rivers. 

A simple isolation will not account for all the facts. To account for the 
poverty we must assume either that the isolation took place before the origin of 
the present variety in the lowland, or that conditions altered so that most of 
the great variety of the lowland became extinct. The first horn of this dilemma 
assumes that the fauna as a whole is a relict of the original fauna, which we have 
shown to be most improbable. I am not prepared to satisfactorily deal with the 
other horn of the dilemma. The elevation at the present time is not sufficient to 
exclude these various lowland types. I do not know of any evidence that other 
unfavorable conditions have obliterated the fauna of the plateau. 

D. Does the fauna consist of recent immigrants? 

If it consists of recent immigrants only, we must assume that the plateau 
became isolated before the origin of the fauna of the lowland, or again, that at 
some time it became elevated to such a height that practically the entire fauna 
was wiped out, and later restored by immigrants. Assuming that one or the other 
of these alternatives is a fact, we may discuss the possibility of the immigration of 
species. 

In this connection the word "migration" as applied to fishes needs defini- 
tion. It is applied to such journeys as that of the eel to the ocean, or that of the 
salmon toward the headwaters, for purposes of reproduction. Such trips, although 
very long, probably only incidentally influence the dispersal of fishes. On the 
other hand, some species are natural pioneers, found always in the rivulets of the 
headwaters, as far up as they can get. If the headwater is advanced a few feet, they 
advance with it. Their migration from one system to another is not miraculous. 
To find such fishes on opposite sides of a low water-shed presents no mystery. If 
by a sudden freshet two rivulets join for but a short time, these species are present 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 103 

to take advantage of the temporary union, and frequently do take advantage of it. 
Such species usually have a very wide distribution. 

In other regions where falls as high as the Kaieteur are the only means of 
migration, they are effective barriers to the downward as well as upward migration 
of fishes. It would seem, however, from examining the distribution in the preceding 
list of species 2, 8, 9, 10, and 20, that in some way or other fishes succeed in getting 
down from the plateau. Some of these species, especially 2, 8, and 10, are abundant 
above the fall, while below it they were taken at Tukeit only, or but a few miles 
farther down the river. They are evidently fishes of the plateau which in some way 
have made their way down. 

In contrast to these we have the species numbered 1, 4, 7, 9, 11, 12, 14, 15, 16, 
17, 18, 18a, and 21, abundant everywhere below, but also found on the plateau. 

These species probably came up from below. They certainly did not ascend 
the Kaieteur. The fact that a number of species got down may imply unknown 
means of ascent and descent near the Kaieteur. Whether any of them ascended 
from the side of the Amazon I cannot say. It is quite probable, as all are found 
in the Amazon. 

The method of ascent of vertical walls by members of the genus Rivulus, one 
of which is found on the plateau, is of great interest. One of these fishes taken in 
Shrimp Creek jumped against the vertical face of a huge rock and clung by the 
adhesion of its tail. From this point by another flop it made and clung to a point 
much higher up the face of the rock. I do not know how high this genus would be 
able to climb a vertical wall. It certainly would not be able to ascend the face 
of the Kaieteur, but there may be smaller rivulets up one of which it might have 
made its way. 

The fact that a very large part of the fauna consists of species of the widest 
distribution, or of local species of genera of the widest distribution, seems to make 
the recent settlement of the plateau by some of the species certain. 

E. Whether or not the fauna is a mixture, the genera and species of the remain- 
ing group "c," i. e., Lithogenes villosus, Corymbophanes andersoni, Helogenes marmo- 
ratus, and Poccilocharax bovallii should answer. 

Now Corymbophanes differs from Plecostomus in trifling characters only. The 
genus Plecostomus is one of the widely distributed genera of South America, being 
found on both slopes of the Andes and from Panama to Buenos Aires. Corymbo- 
phanes may therefore be a local modification of a comparatively recent immigrant 
to the plateau. 

Helogenes marmoratus, on the other hand, is found in the Essequibo basin 



104 MEMOIRS OF THE CARNEGIE MUSEUM 

only. It is a very aberrant Nematognath, with no relatives in other parts of South 
America. It may be a remnant of the original forms. 

Pcecilocharax stands alone in the Characince, its only near relative being 
Crenuchus, found in the Essequibo and Amazon. It also may be a left-over. 

This leaves Lithogenes villosus the only genus of the Loricariidce with the 
armature reduced to a few prickles. Whether we regard this nakedness as primitive 
or as secondarily acquired it points to a long separation from the other Loricariidce, 
and Lithogenes may also be a left-over. 

The evidence seems, then, to favor the conclusion that the larger part of the 
fauna of the upper Potaro has been more or less recently acquired, and that a 
smaller part is composed of relicts of the original fauna of the Guiana Plateau. 
This conclusion is, however, but tentative. Nothing is known about the fauna or 
physical condition of the rest of the Guiana plateau except what follows under the 
next head. The only other collections made were those of Richard Schomburgk, 
and they were all lost. It is highly desirable, therefore, to collect about Roraima, 
in the streams flowing in different directions. 

Fishes of the Ireng River. 

The following list may serve as a cross-reference to the preceding list of the 
Upper Potaro. The names of species common to the Potaro and the Ireng are 
here italicized. The Maripicru is a branch of the Ireng between Wontyke and 
Karakara above the Karona Falls. Chipoo is between Karakara and the Rupununi 
and is probably below the Karona Falls. The location of Nickaparoo was not 
given me. 

The total list of species suggests that we may expect to find a number of 
additional species in the Upper Potaro. 

Maripicru. Chipoo. Nickaparoo. 

1. Chasmocranus longior 3 

2. Rhamdia quelen 3 8 

3. Trachycorystes galeatus 4 

4. Cdttichthys callichthys 1 1 

.5. Hoplosternum thoracatum 1 

6. Plecostomus hemiurus 2 

7. Ancistrus temmincki 1 2 

8. Ancistrus cirrhosus. 1 

9. Loricariichthys steward 12 

10. Prochilodus maripicru 3 

1 1 . Parodon bifasciatus 1 

12. Chilodua punctatus 1 

13. Charicidium fasciatum 21 

14. Pyrrhulina filamentosa 14 

15. Leporinus granti 9 

1 Near Holmia. 



1 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 105 

16. Aphyocarax erythrurus 1 

17. Mocnkhausia oligolepis 1 

18. Creatochanes affinis 35 

19. Poecilocharax bimaculatus 1 

20. Hoplias macrophthalmus 2 

21. Hoplias malabaricus 3 3 

22. Hoplerythrinus unitmnialus 

23. Erylhrinus erythrinus 16 

24. Gymnotus carapo 1 32 

25. Eigenmannia virescens 3 5 

26. Hypopomus brerirostris 2 4 

27. ^Equidens geayi 1 

28. Mquidens potaroensis* ' 

29. Cichlasoma bimaculatum 2 

30. Heterogramma steindachneri 2 

31. Crenicichla alia ^ 

1 Near Holmia. 



CHAPTER VII. 

GENERAL CONSIDERATIONS. 

A number of interesting and important facts, bearing on general biological 
problems, are incidentally dealt with in the systematic portion of this paper. 
Inasmuch as it is not at all to be expected that anyone would read through the 
mass of details to discover them they are extracted and presented here. 

"Unnatural Natural History." 

The skeletons of a variety of the Ariince are prepared and sold as "crucifix 
fishes." The one which is most frequently prepared is Sciadeichthys proops (Plate 
VI). The dorsal surface of the skull and dorsal plate are pointed out as resembling 
a hooded monk with outstretched arms. The ventral surface resembles the 
cross. Fancy pictures the dorsal spine as a representation of a spear, while the 
otoliths, which rattle when the skull is shaken, are the dice with which the 
soldiers cast lots for the garment of our Lord. 

Skulls of the Aspredinince are put together to form a "crown of thorns." 

Jordan's Law. 

If we should find specimens of any group with such slight differences as there 
are between Crenicichla saxatilis and alta or Mquidens vittatus and potaroensis 
generally present at any locality we should probably consider them as variations 
without special significance. The differences must, however, be of distinct sig- 
nificance, if thej- are coordinated with the environment in such a way that one can 
predict what the form wiU be at any locality. 

In the present paper such forms have been given specific designation. Thus 
Mquidens vittatus of the lowlands is replaced by Mquidens potaroensis in the Potaro 
River, both above and below the Kaieteur. Similarly Crenicichla alta replaces 
Crenicichla saxatilis, the two forms overlapping at Rockstone. Similar replace- 
ments of lowland species by highland species are abundant. Rhamdia quelen of 
the upper Potaro replaces Rhamdia sebce of the lowland. Helogenes marmoratus 
replaces Hypophthahnus edentahis. Plecostomus hemiurus replaces Plecostomns 

106 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 107 

watwata of the lower courses. Moenkhausia browni replaces Moenkhausia grandi- 
squamis, Crcatochanes affinis replaces Creatochanes melanurus, Chalcinus rotundatus 
replaces Chalcinus elongatus, Charax rupununi replaces Charax gibbosus, Pinielodella 
cristata and P. megalops replace P. macturki. 

In a number of other places the replacement is not so conspicuous. In several 
of the above mentioned cases the species overlap. In some of the cases there is 
quite evident genetic connection between the two mutually excluding forms. In 
other cases the genetic connection, while evident, is certain y remote, as in the 
case of Crenuchus and Pcecilocharax, for instance, and in still other cases the relation 
may be apparent rather than real, i. e., one or both forms may have immigrated to 
adapted localities, and not have become differentiated in their present habitat. 

In so far as two of the above pairs represent local adaptations, that is, in- so 
far as one or both members of the pair are autochthons, thus far do they give evi- 
dence in support of Jordan's Law. Where, however, we find such cases in support 
of the law, there are many others where the more closely related species occupy the 
same territory and are contrary to it. We may cite Phenacogaster megalostictus and 
rnicrostictus; Chasmocranus longior and brevior; Doras hancocki and cataphracta; Curi- 
matus microcephalics and spilurus; Characidium pellucidum, C. pteroides and C. cate- 
natum; Pozcilobrycon trifasciatus, P. erythrurus and P. ocellatus. It may be said in 
favor of Jordan's Law that in some of the cases in which we are certain that the 
forms are immediately related {Crenicichla and JEquidens) its postulates are 
undoubtedly sustained. 

Mutation. 
Two instances of apparent mutation may be mentioned. 

1. Moenkhausia profunda differs from Fowlerina orbicularis apparently only 
in the generic characters. I say apparently, for it is to be borne in mind that in 
comparing "specimens" of fishes we are put on a level with the ornithologist who 
might be compelled to compare plucked specimens of the Orchard and Baltimore 
Orioles. It is doubtful whether he would draw correct conclusions as to their song 
and nesting-habits from such data. Similarly Moenkhausia profunda and Fowlerina 
orbicularis may differ from each other much more than the characters of speci- 
mens seem to indicate. Granting that the two species are as similar as they appear 
to be it is quite probable that the former is a recent mutant of the latter. Fowlerina 
is exceedingly abundant in the Essequibo. Moenkhausia profunda is known by but 
two specimens from the northwestern coast. (Plate XLVI, figs. 1 and 2.) 

2. The second instance is complex and indicates simultaneous, orthogenic 
mutation in a number of not closely related species of the same family. 



108 MEMOIRS OF THE CARNEGIE MUSEUM 

In different species of the Nannostomatince, Tetragonopterinas and the Chara- 
cince the pectoral has at times been arrested in its normal development. It has 
retained the embryonic form. Inasmuch as I had never seen a similar condition 
in other fishes the first specimen was described as a distinct genus. Mrs. Ellis 
at once found another. Mrs. Ellis then made a systematic search for similar mu- 
tants in the large collections made, not only by myself, but also among the Tetra- 
gonopterince collected by Mr. Haseman in various parts of Brazil. She reports : 

The specimens with an archaic pectoral were forty-four in number, belonging 
to eight different species of five different genera and three different subfamilies, 
as follows: 

Archicheir minutus Eigenmann, one specimen, 26 mm., Christianburg (Car- 
negie Museum Catalog of Fishes No. 1186). 

Dermatocheir catablepta Durbin, one specimen, 18 mm., Tumatumari, British 
Guiana (C. M. Cat. No. 1198). 

Hyphessobrycon parvella Mrs. Ellis, one specimen, 18 mm., Riberao, Azula 
Lagoa (C. M. Cat. No. 2930); one specimen, 12 mm., Rio Tiete (C. M. Cat. No. 
2931), with archaic pectorals. Thirteen specimens, 13 to 29 mm. (No. 2932), 
Aqua Quente, Alagoinhas, Rio Catu, Queimadas, Rio Itapicuru, have normal 
pectorals. 

Hyphessobrycon lutkeni (Boulenger), four specimens, 12, 16, 16, and 19 mm. 
(without the caudal), Jacarehy (C. M. Cat. No. 2933), have archaic pectorals. 
Three specimens, 19, 19, and 20 mm. (without the caudal), Jacarehy, (No. 2937), 
have normal pectorals. The pectorals are also normal in thirteen hundred and 
seventy-four specimens, 23 to 65 mm., from Rio Grande do Sul, Paraguay basin, 
and the coastwise streams of southern Brazil. 

Hyphessobrycon bifasciatus Mrs. Ellis, twenty-seven specimens, 15-25 mm., 
Cacequy (C. M. Cat. No. 2935); and five specimens, 18 to 27 mm., Munez Freire 
(C. M. Cat. No. 2936), have archaic pectorals, while one hundred and eighty-four 
specimens, 25 and 29 to 47 mm., from Campos, Sao Joao da Barra, Xiririca, Porto 
Alegre, Morretes, Munez Freire, Lagoa Feia, and Cacequy have pectorals of the 
adult type. 

Hasemania maxillaris Mrs. Ellis, one specimen, 29 mm., from Porto Uniao, 
Rio Iguassu (C. M. Cat. No. 2937). 

Hasemania bilineatus Mrs. Ellis, four specimens, 14 to 16 mm., from Mogy das 
Cruzes, Rio Tiete (C. M. Cat. No. 2938) have archaic fins; five specimens, 20 to 
41 mm. (2939), from Mogy das Cruzes, Alto da Serra, Sao Paulo, have normal 
pectorals. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 109 

Charax gibbosus (Linmeus), four specimens, 29 to 33 mm., Botanic Garden, 
near Georgetown, British Guiana (C. M. Cat. No. 2940). 

Asiphonichthys hemigrammus Eigenmann, two specimens, 27 mm., Gluck 
Island (C. M. Cat. No. 2138, 1. U. Cat. No. 12044); one specimen, 25 mm. (without 
the caudal), Gluck Island (I. U. Cat. No. 12645), have archaic pectorals. One 
specimen, 33 mm. (with the caudal), Gluck Island (C. M. Cat. No. 2941), has a 
normal pectoral. 

In contrast to the species of Hyphessobrycon enumerated above we have one 
thousand nine hundred and ninety-nine specimens of Hyphessobrycon gracilis be- 
tween 19-30 mm., all with normal fins. 

Whether any of the forms here enumerated are permanent, or simply abnormal 
individuals, doomed to elimination, the interesting fact remains that a very unusual 
mutation is arising simultaneously in widely different members of the same family. 
This is of special interest in the case of the characins, for it seems quite certain that 
other characters have independently made their appearance in different subfamilies. 
A pair of conical teeth in the lower jaw belongs to this category. They are found 
in widely distinct subfamilies both in Africa and America. A triple series of 
teeth in the maxillary is another character that has been several times and inde- 
pendently derived from a double series, and the double series from a single series. 
The steps in this process have been preserved in part. The process in the latter 
cases is again orthogenic, but it is doubtful whether progress is made by mutation. 

Changes of Color and Shape with Age. 

Marked changes in color take place with growth in Cichla. Only melanism is 
taken into account. In the smaller specimens there is a series of three conspicuous 
spots on the sides (Plate LXIX, fig. 1). These become ocellated a little later, at 
the same time that vertical dark bands appear (fig. 2). With growth the two 
anterior spots disappear entirely, the last one being retained as a caudal ocellus 
(fig. 3). The sides are marked at this stage with three heavier, and a number of 
fainter, cross-bands. With full growth the bands become concentrated into ir- 
regular spots surrounded by lighter (fig. 4). 

Changes in the color of Crenicichla alta are sufficiently described in the diagnosis 
of the species. 

The changes in color in Myloplus rhomboidalis and Myleus pacu are indicated 
in Plates LVIII and LIX. In the figure of the adult M . pacu irregular black blotches, 
which are frequently present, are not indicated. In both these species there is a 
notable change in shape with age. The young are much slenderer, depth 2.6 in 



110 MEMOIRS OF THE CARNEGIE MUSEUM 

the length in the young M. pacu, as compared with 1.6 in the adult; 2.4 in the 
length in the young Myloplus rhomboidalis as compared with 1.5 in the adult. 
Similar changes in shape take place in Serrasalmo rhombeus and probably in all of 
the other characins with an extremely deep body In this connection figures 2 and 
3 of Plate LII should also be examined; they represent the change in shape in 
another type of characins. 

On the Utilization of Different Structures to Obtain the Same End. 

(Plates V-IX.) 

In a number of Siluridce, especially the marine Ariince, the nuchal region is 
heavily armored. Granting that this armor is an adaptation, it is of interest that 
it is formed of either the occipital process, the so-called dorsal plate, or combinations 
of the two in varying proportions. 

In Sciadeichthys flavescens (Plate V, fig. 1) the entire armature is furnished 
by the dorsal plate. In proops (Plate V, fig. 2) the occipital process takes a slight 
part, the major portion of the armature being formed by the dorsal p'ate. In 
parkeri (Plate V, fig. 3) the occipital process is still more prominent. In Sciadeichthys 
emphysetus (Plate IX, fig. 1) the dorsal plate and occipital process are of about equal 
value. In the two species of Selenaspis, S. herzbergii and S. passany (Plate VII) the 
occipital process is slightly larger than the dorsal plate. In Arius spixii and Hex- 
anematichthys rugispinis (Plate IX) the dorsal plate forms a negligible portion 
of the armature. It is still further reduced in the three species of Notarius (Plate 
VIII) in which the occipital process differs progressively from the linear form in 
N. stricticassis to the leaf-shaped in N. grandicassis. In the latter three species 
there is very great variation. 

The series outlined above is not a genetic series. It is simply a series showing 
the inversely proportioned coordinated development of the structures to accomplish 
the arming of the nuchal region. They illustrate the dictum of Weismann that 
"adaptations arise if they are at. all possible" and that the structures utilized in 
bringing out the adaptation are not material. Natural selection would be satisfied 
with the arming of the nuchal region regardless of the structure that did the arming. 64 

A similar case is furnished by the genera Charax, Asiphonichthys, Acanthocha- 
rax and Heterocharax. In these a spinous armor for the lower gill-region, or breast, 
may be considered an adaptation. In the first two genera the clavicle furnishes 
the spine. Its lower edge rises blade-like and ends in a spine anteriorly and pos- 

64 Dr. C. R. Eastman calls my attention to the fact that a similar armoring has developed in Coccosteus, 
Dinichthys, and other extinct fishes. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 111 

teriorly. In the latter two genera the clavicle is free from spines, but the preopercle 
is provided with a spine at its lower angle. Granted that the presence of a spine 
was advantageous at this point, it is evident that natural selection might pre- 
serve two different lines of individuals which varied in this direction. 

Mutilation. 

Mutilated specimens which would not have survived, if there were the close 
individual selection and elimination which we have imagined, are not rare. 

A Potamotrygon evidently had a piece bitten out of the side by a " Perai." An 
Astyanax abramoides had a mutilated snout of long standing, although it was the 
largest specimen of the species obtained. 

A Loricaria brunnea had lost the posterior portion of the body and had re- 
generated a caudal fin. A Trachycorystes obscurus had suffered a similar injury 
and regenerated the caudal. Several specimens of Char ax gibbosus and Eigen- 
mannia virescens had suffered a variety of injuries. A detailed study of the mutila- 
tions in the gymnotid eels will be published in a monograph on the Gymnotidoe, 
which has been prepared by Dr. Max Ellis, and which will shortly appear in the 
Memoirs of the Carnegie Museum. 

The Characins. 

This family will be fully dealt with in another place, but a few of the new 
points brought out by the present expedition may be mentioned. 

More than half of the strictly fresh-water fauna of Guiana is composed of 
characins. In all there are one hundred and fifty-one species. In all localities, 
except Lama Stop-Off, the Georgetown trenches, Waratuk, the Packeoo Falls, and 
the Rupununi and Aruataima, they form more than half the number of species. 
It was found that some of the small species (Plate XXXIX, figs. 3-7) burrow on 
the sand-banks like some of the North American darters, and that some species 
actually fly for a short distance after scooting along the surface of the water for a 
much longer distance. The characins are thus found in the bottom below the 
river and in the air above it. It has long been known that different members are 
adapted to, and live in, all the regions between the two. 

The organs of flight, which have been the subject of study by one of my students, 
consist of the enlarged pectorals and the hypertrophy of the attached muscles. 
To furnish points of origin for the muscles the coracoids are enormously expanded 
and united below into a sternum. The entire anatomy of the anterior half of the 
fish has been modified to become adjusted to this peculiar structure. (Plate LV.) 



112 MEMOIRS OF THE CARNEGIE MUSEUM 

I have elsewhere called attention to the fact that the characins parallel most 
other fishes. For this reason they were distributed by the earlier naturalists 
among various families of fishes. Pcecilocharax, a small species about the Kaieteur, 
looked so nearly like a Pceciliid that only careful scrutiny after my arrival at home 
enabled me to place it where it belongs. (Plate XLIV.) Not only do they parallel 
other species of fishes, but they parallel each other. Moenkhausia lepidurus "mimics " 
Creatochanes caudomaculatus, which frequently lives with it. The young of Ano- 
stomus anostomus (Plate XLI, fig. 1) so closely resemble the young of Leporinus 
arcus (Plate XLII, fig. 2) that a most skilled ichthyologist pronounced them the same 
when the snouts of the two specimens were covered. Some idea of the diversity in 
this family may be gathered by glancing at the plates from Numbers XXXIII to 
LXI. The most interesting discovery was probably Bivibranchia, a characin with 
a protractile upper jaw (Plate XXXIII) and of nearly equal interest was the dis- 
covery of the sexually dimorphic Pcecilocharax (Plate XLIV, figs. 1 and 2). 

Of more general interest was the finding of the young of the "Pacu" in the Wara- 
puta Cataract and elsewhere. The breeding-place of this important food-fish was 
not known, and it had been supposed that it bred on the overflowed land during 
the rainy season. 

Sexual Dimorphism. 

Color differences are as common between the sexes of fishes in Guiana as else- 
where, but it is not the intention to take up these. Red and yellow are frequently 
present. 65 Usually if yellow and red are present in a species the red replaces in 
the male the yellow of the female. 

The secondary sexual differences of the Pmciliidce are varied and great. They 
have often been described, but none of those hitherto described approaches the 
modification in the male of Tomeurus. (Plate LXV, figs. 7 and 8.) The anal fin in 
this species has been moved further forward and is more highly modified than in any 
other member of the family. In Rivulus (Plate LXIII) the female has an ocellus 
on the base of the upper caudal lobe. (See also Plates LXIV and LXV for other 
instances of sexual differences in the Poeciliidos.) 

Great secondary sexual characters are also found in the "Pacu," Myleus, and 
probably in all of the related species of Myloplus. The anal fin in the male is 
bilobed (Plate LIX, fig. 5), the middle rays longer than those either just in front 
or behind them. The anal of the female is falcate (Plate LIX, fig. 6). 

65 In Hyphessobrycon and Hemigravimus the red of the caudal frequently encroaches on the sides of 
the body. The red markings are sometimes very abrupt, as in the caudal of Cichla ocellaris, and in the fins of 
Chalceus macrolepidotus. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 113 

Th? difference between the male and female of Poecilocharax are indicated on 
Plate XLIV, figures 1 and 2. 

In some of the Loricariidie the male is more abundantly supplied with spines. 
In Pseudancistrus barbatus, for instance, the cheeks of the males are provided with 
long bristles. In Lithoxus lilhoides the pectoral spines are much longer in the 
male (Plate XXIX, fig. 4) than in the female (fig. 3) and more profusely provided 
with bristles. 

The peculiar barbels, much more profusely developed on the head of the male 
Ancistrus than on the female, have long been known (Plate XXV, fig. 3). 

New Genera and Species. 
The new genera described during the progress of the work are: 

1. Chamaigenes. 15. Paecilobrycon. 

2. Agmus. 16. Archicheir. 

3. Megalonema. 17. Poecilocharax. 

4. Microglanis. 18. Aphyodite. 

5. Brachyglanis. 19. Dermatocheir. 

6. Leptoglanis. 20. Camegiella. 

7. Myoglanis. 21. Acanthocharax. 

8. Chasmocranus. 22. Heterocharax. 

9. Tympanopleura. 23. Gymnorhamphichthys. 

10. Lithogenes. 24. Porotergus. 

11. Corymbophanes. 25. Rhinosardinia. 

12. Lithoxus. 26. Tomeurus. 

13. Bivibranchia. 27.- Acarichthys. 

14. Tijlobronchus. 28. Soleonasus. 

The new species of fresh-water fishes, based on the collections made, are: 

1. Bunocephalus amour us. 14. Chasmocranus brevior. 

2. Bunocephalus chamaizelus. 15. Pimelodella megalops. 

3. Agmus lyriformis. 16. Pimelodella macturki. 

4. Megalonema platycephalum. 17. Pimelodus heteropleurus. 

5. Pseudopimelodus villosus. 18. Leptodoras linnelli. 

6. Pseudopimelodus albomarginatus. 19. Hemidoras microstomia. 

7. Microglanis poecilus. 20. Hemidoras micropaeus. 

8. Brachyglanis frenata. 21. Hemidoras leporhinus. 

9. Brachyglanis 7nelas. 22. Hemidoras notospilus. 

10. Brachyglanis phalacra. 23. Auchenipterus demerara. 

11. Leptoglanis essequibensis. 24. Auchenipterus brevior. 

12. Myoglanis potaroensis. 25. Tympanopleura piperata. 

13. Chasmocranus longior. 26. ^IgeneiosMS guianensis. 



114 



MEMOIRS OF THE CARNEGIE MUSEUM 



27. Ageneiosus marmoratus. 

28. Hemicetopsis macilentus. 

29. Hemicetopsis minutus. 

30. Pygidium guianense. 

31. Pygidium conradi. 

32. Pygidium gracilior. 

33. Plecostomus hemiurus. 

34. Lithogenes villosus. 

35. Corymbophanes andersoni. 

36. Hemiancistrus braueri. 

37. Pseudancistrus nigrescens. 

38. Lithoxus lithoides. 

39. Loricariichthys microddn. 

40. Loricariichthys griseus. 

41. Loricariichthys stewarti. 

42. Farlowella hargreavesi. 

43. Bivibranchia protractila. 

44. Curimatus morowhannce. 

45. Curimatus issororoensis. 

46. Prochilodus maripicru. 

47. Tylobronchus maculosus. 

48. Paradon bijasciatus. 

49. Nannostomus marginatus. 

50. Nannostomus minimus. 

51. Nannostomus simplex. 

52. Pacilobrycon harrisoni. 

53. Pcecilobrycon erythrurus. 

54. Pcecilobrycon ocellatus. 

55. Archichcir minutus. 

56. Characidium laterale. 

57. Characidium vintoni. 

58. Characidium blennioides. 

59. Characidium pellucid um. 

60. Characidium pteroides. 

61. Characidium catenatum. 

62. Anosfowus plicatus. 

63. Schizodontopsis laticeps. 

64. Leporinus arcus. 

65. Leporinus granti. 

66. Leporinus alternus. 

67. Poecilocharax bovallii. 

68. Aphyocharax melanotus. 



69. Aphyocharax erythrurus. 

70. Aphyodite grammica. 

71. Mcenkhausia profunda. 

72. Mamkhausia brown i. 

73. Mcenkhausia shidleri. 

74. Pri stella aubynei. 

75. Hemigrammus erythrozonus. 

76. Hemigrammus rodwayi. 

77. Hemigrammus iota. 

78. Hemigrammus orthus. 

79. Hemigrammus cylindricus. 

80. Hemigrammus analis. 

81. Hyphessobrycon minor. 

82. Hyphessobrycon rosaceus. 

83. Hyphessobrycon minimus. 

84. Hyphessobrycon eos. 

85. Hyphessobrycon strictus. 

86. Dermatochcir catablepta. 

87. Crcagrutus melanzonus. 

88. Bryconamericus hyphessus. 

89. Astyanax guianensis. 

90. Astyanax essequibensis. 

91. Astyanax mutator. ■ 

92. As<yanaa; mucronatus. 

93. Pweilurichthys abramoides. 

94. Pcecilurichthys potaroensis. 

95. Deuterodon potaroensis. 

96. Deuterodon pinnatus. 

97. Phenacogaster megalostictus. 

98. Phenacogaster microstictus. 

99. Brycon siebenthali. 

100. Pygocentrus bilineatus. 

101. Raeboides thurni. 

102. Charax rupununi. 

103. Asiphonichthys hemigrammus. 

104. Cynopotamus essequibensis. 

105. Acanthocharax microlepis. 

106. Heterocharax macrolepis. 

107. Acestrorhynchus nasutus. 

108. Gymnorhamphichthys hypostomus. 

109. Sternarchus leptorhynchus. 

110. Porotergus gymnotus. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



115 



111. Porolergus gimbeli. 

112. Rhinosardinia serrata. 

113. Stolephorus guianensis. 

114. Rivulus breviceps. 

115. Rivulus holmiw. 

116. Rivulus waimacui. 

117. Rivulus stagnatus. 

118. Rivulus lanceolatus. 

119. Rivulus frenalus. 



120. Acaitthophacelus melanzonus. 

121. Acanthophacelus bifurcus. 

122. Tomeurus gracilis. 

123. Nannacara bimaculata. 

124. JEguidens potaroensis. 

125. Heterogramma ortmanni. 

126. Crenicichla alia. 

127. Dormitator gymnocephalus. 

128. Soleonasus finis. 



CHAPTER VIII. 

SYSTEMATIC ACCOUNT OF THE FRESHWATER FISHES 

OF BRITISH GUIANA. 

Class SELACHII. 

Order BATOIDEI. 

Suborder MASTICURA. 

Whip-tailed Rays. 

Family I. DASYATID.E. 

Tail abruptly slender, its back usually with a serrated spine; pectoral fins 
uninterrupted, confluent around the snout; teeth small; nasal valves forming a 
flap, which is joined to the upper jaw by a narrow frenum; spiracles large. 

Subfamily Potamotrygonin^e. 
Pelvis with a sword-shaped cartilage extending forward in the mid-ventral line. 

Key to the Guiana Genera of Potamotrygonin^e. 
a. Tail with irregular thorns on its upper surface, and with a large spine. 

6. Mouth with papilla?; teeth in more than twenty-five rows Potamotrygon. 

66. Mouth without papilla 1 ; teeth in less than twenty-five rows Paratrygon. 

an. Tail with many short spines about its base Elipesurus. 1 

Potamotrygon Carman. 
Tamiura Muller and Henle, Bericht. K. Preuss. Akad. Wiss., 1837, 117 {ornatum). 
Potamotrygon Garman, Proc. Bost. Soc. Nat. Hist., 1877, 210. 
Type, Pastinaca humboldtii Roulin. 

1. Potamotrygon hystrix (Muller and Troschel). 
? Pastinaca humboldtii Roulin, Ann. Sc. Nat,, XVI, 1829, 104, pi. 3 (Meta).- 

Dumeril, Hist. Nat, Poiss., I, 1865, 625 (copied). 
Potamotrygon humboldtii Carman, Proc. Bost, Soc. Nat, Hist,, 1877, 210. 
Trygon hystrix Muller and Henle. Syst. Beschr. Plagiostomen, 1841, 167. — Val- 

1 Elipesurus was taken by Schomburgk in the Rio Braneo, and may occur in the Essequibo basin also. 

116 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 117 

enciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 11, pi. 15 (La Plata 
to Amazon). — Schomburgk, Fishes Brit. Guiana, II, 1842, 180, pi. 20 
(Roowa). — Muller and Troschel, in Schomburgk, Rciscn, III, 1848, 644 
(Rupununi; Takutu; Rcwa). — Castelnau, Anim. Am. Sud, Poiss., 1855, 103 — 
Dumeril, Hist. Nat. Poiss., I, 1865, 608 (Rio de Janeiro; Lake Maracaibo; 
Buenos Aires). — Gunther, Catalogue, VIII, 1870, 482 (Santarem; Surinam). 
Potamotrygon hystrix Eigenmanx and Kennedy, Proc. Acad. Nat. Sci. Phila., 

1903,498 (Asuncion). 
Tceniura motoro Muller and Henle, Syst. Beschr. Plagiostomen, 1841, 197 
(Cuyaba). — Muller and Troschel, in Schomburgk, Reisen, III, 1848,642 
(Mouth of the Zuruma).— Dumeril, Hist. Nat. Poiss., I, 1865, 624 (Rio de 
Janeiro). — Gunther, Catalogue, VIII, 1870, 484. 
Trygon garrapa Schomburgk, Fishes Brit, Guiana, II, 1842, 182, pi. 21 (Rio 
Branco). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 642 
(Rupununi; Takutu; Rio Branco). 
Tceniura orbignyi Castelnau, Anim. Am. Sud, Poiss., 1855, 102, pi. 49, fig. 1 — 
Dumeril, Hist, Nat. Poiss., I, 1865, 624 (Tocantins). — Gunther, Catalogue, 
VIII, 1870, 484.— Steindachner, " Flussfische Sudamerika's," i, 1879, 11 
(Ciudad Bolivar) . 
Trygon miilleri Castelnau, Anim. Am. Sud, Poiss., 1855, 102, pi. 48, fig. 2.— 

Dumeril, Hist, Nat, Poiss., I, 1865,621 (RioCrixasand Araguay). 
Trygon henlei Castelnau, Anim. Am. Sud, Poiss., 1855, 102, pi. 48, fig. 3.— 
Dumeril, Hist. Nat. Poiss., I, 1865, 623 (Tocantins). 
One specimen, 147 mm. Konawaruk. (C. M. Cat. No. 1737.) 
Three specimens, 158, 181, and 174 mm. across the disk. Rockstone sand- 
bank. (C. M. Cat. No. 1738; I. U. Cat. No. 12101.) 

Five papillae behind the teeth of the lower jaw. Oval, disk but little longer 
than broad, without projecting snout; eye about 2 in the interocular space; 
interorbital 2 or less in the distance from the tip of the disk to the line between 
the anterior margins of the eye; middle of back tuberculate, becoming smooth at the 
margin of the disk; irregularly placed thorns along the middle of the tail in front of 
the serrated spine, and a lower ventral fold (tails of all the specimens broken a short 
distance behind the spine). 

Back brown with obscure rounded lighter spots, decreasing in size to fine 
vermiculations on the fin (garrapa of Schomburgk) ; in the smaller specimens the 
darker areas about the light spots are intensified into four to seven black spots, 
two of which are sometimes confluent, forming an hour-glass, or less regular streak 



118 MEMOIRS OF THE CARNEGIE MUSEUM 

{histrix of Schomburgk) ; sides of tail banded, lower surface of tail marbled: a small 
black spot near the middle of the belly. 

Paratrygon Dumeril. 
Paratrygon Dumeril, Hist. Nat. Poiss., I, 1865, 594. 
Disceus Garman, Proc. Bost. Soc. Nat. Hist., 1877, 208. 

Type, Raja orbicularis Bloch and Schneider. 

This genus is distinguished from Potamotrygon, among other characters, by the 
absence of papilla? in the mouth and by the smaller number of teeth. 

2. Paratrygon orbicularis (Bloch and Schneider). 
" Aiereba" Marcgrave, in Piso, De India?, etc., 1658, 175 (copied by Jonston, De 

Pise, pi. 38, fig. 6, and Willughby, 68, pi. 101, fig. 2). 
Raja orbicularis Bloch and Schneider, Syst. Ichth., 1801, 361. 
Trygon orbicularis Gunther, Catalogue, VIII, 1870, 482 (copied). 
Trygon strongyloplera Schomburgk, Fishes Brit. Guiana. II, 1842, 183, pi. 22 

(Rio Branco). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 642 

(Rupununi; Takutu; Rio Branco). — Gunther, Catalogue, VIII, 1870, 476 

(copied) . 
Trygon aiereba Dumeril, Hist. Nat. Poiss., I, 1865, 592 (Brazil). 

No specimens were secured. 

Disk ovate, scarcely longer than broad; eyes very small; plain or with un- 
dulating stripes. 

Class TELEOSTOMI. 

Key to the Orders of Teleostomi found in the Fresh-waters of Guiana. 
a. Weberian ossicles present; the anterior vertebrae coalesced. A single rayed dorsal fin, usuallyfollowed 
by an adipose fin. 
b. Skin naked or with bony plates; maxillary rudimentary, forming the base of a barbel.. Nematognathi. 
bb. Scales well-developed (rarely naked); maxillary not forming the base of a barbel. 

c. Body not eel-shaped (an adipose fin usually present) Heterognathi. 

cc. Body elongate, more or less eel-shaped, the anal fin very long Glanencheli. 

aa. No Weberian ossicles; the anterior vertebra not united. 

d. Air-bladder connected with the alimentary canal by an open duct; ventral fins abdominal; no 
spinous dorsal. 

e. A mesocoracoid; body not eel-shaped Isospondyli. 

ee. No mesocoracoid; parapophyses coossified with centra. 
/. Body eel-shaped, no paired fins; no separate caudal. 

g. Gill-opening single, ventral; premaxillaries normally developed Symbranchii. 

(gg. Gill-openings not ventral; premaxillaries rudimentary or wanting. Apodes.) 2 

ff. Body not eel-shaped; paired fins; a well-developed caudal fin Microcyprini. 

2 Midler and Troschel (Schomburgk, Reisen, III, 1848, 639) record Gymnothorax ocellatus from 
plantation drains, and the fresh-water eel probably enters the Guiana rivers at times. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 119 

dd. Duct of air-bladder closed. 

h. Ventral fins sub-abdominal; lower pharyngeals separate. 

i. Snout tubiform; mouth terminal, toothless; parietals absent; pterotic extending down- 
ward to basioccipital; gills lobate; body armed with dermal plates. . . Lophibranchii. 
ii. Snout not tubiform; parietals present; pterotic not reaching basioccipital; body not 

armed; ventral fins of a spine and five rays Percesoces. 

hh. Ventral fins thoracic. 

j. Gill-openings large; a spinous dorsal, or the dorsal very long. 

k. Cranium symmetrical Percomorphae. 

kk. Cranium asymmetrical Heterosomata. 

jj. Gill-opening small; maxillary and premaxillary united; no ribs Plectognathi. 

Order NEMATOGNATHI. 

Key to the Families of Nematognathi. 
a. Body naked or with a single series of plates along the middle of the sides. Mouth terminal or sub- 
terminal. 
b. Opercle minute, a mere vestige; neural spines of the coalesced vertebra? forming a ridge from the 
occipital to the dorsal. Caudal vertebrae greatly compressed, their neural spines expanded. 
Gill-openings reduced to a slit in front of the pectorals. Air-bladder well-developed. No 
adipose fin. Teeth villiform. Nares remote. Dorsal short, over the ventrals. Pectoral 

witli a strong spine Aspredinidae, II. 

bb. Opercle well-developed. Gill-openings usually wide. Caudal vertebras not compressed, the 
neural spines spine-like. Maxillary a vestige. 
c . Air-bladder well-developed, simple or with transverse constrictions, lying free in the abdominal 
cavity. Body naked or with a single series of plates along the middle of the sides; 
an adipose fin. 

d. Dorsal over abdominal portion of the vertebral column; anal not very long, its origin 

far behind the vertical from the dorsal fin SUuridae, III. 

dd. Dorsal over caudal portion of the vertebral column; anal very long, nearly co-extensive 
with the tail, its origin far in advance of the vertical from the dorsal; air-bladder 

transversely elongate, reniform, not covered by bone Helogeneidae, IV. 

cc. Air-bladder double, a minute one on either side of the coalesced vertebra?. 

e. A small adipose fin. Dorsal over the anal, which is very long, origin of anal near the 

origin of the second third of the length. Air-bladders enclosed by the lateral 
processes of the coalesced vertebra?, the scapula and the process connecting the 
scapula with the basioccipital. An adipose fin. Anal of 34 or more rays. 

Hypophthalmidae, V. 
ee. No adipose fin; anal short, posterior; dorsal usually in advance of the anal, sometimes far 
back and over the short anal or behind the origin of the anal in Tridens. Air- 
bladder double, a minute one on each side, enclosed by the lateral processes 

of the coalesced vertebra? only. Anal short Pygidiida?, VI. 

aa. Sides with two series of plates; caudal vertebra? normal, the neural and ha>mal spines spike-like, 
separate from each other. Air-bladders minute, one on either side of the coalesced vertebra? 
and surrounded by a bony capsule, in contact with the skin at a long narrow slit in the temporal 
plate and at the last of a series of slits below the longer one. Mouth terminal; teeth villiform. 

Callichthyidae, VII. 



120 MEMOIRS OF THE CARNEGIE MUSEUM 

aaa. Derm more or less completely covered with several series of bony plates; caudal vertebra? compressed, 
the neural and haemal spines expanded, forming a continuous ridge above and below. Air- 
bladder minute, one on either side of the coalesced vertebra 1 , and surrounded by a bony capsule, 
in contact with the skin at a notch in the posterior margin of the temporal plate at the beginning 
of the lateral line. Mouth inferior, the lower lip reverted, the lips disk-like; teeth (if present) in 
many series, a single series erect Loricariidae, VIII. 

Family II. ASPREDINID.E. 

The "Banjamans" (banjoman). 

= Aspredinoidei Bleeker, Nederl. Tijclschr. Dierk., I, 1863, 117. 

= Aspredinina Gunther, Catalogue, V, 1864, 266. 

= Aspredinidce Gill, Arrangement of the Families of Fishes, 1872, 19. 

= Bunocephalidw Eigenmann and Eigenmann, Am. Nat., 1888, 647; Occasional 

Papers Cal. Acad. Sci., I, 1890, 12. 

Characters given in the key to the families, p. 119. 

Key to the Genera of Aspredinid^e. 
a. Tail long, with a median dorsal fold; distance of vent from tip of snout less than half its distance 
from base of caudal. A. 50-60. (Aspredinina.) 
b. A series of barbels from the corner of the mouth along the breast and anterior part of abdomen; 
maxillary barbel with a smaller barbel at its base. 

c. Tip of snouth smooth, ethmoid without hooks; a single pair of mental barbels (rarely wanting). 

Chamaigenes. 
cc. Tip of snout (nasals and ethmoid) with four broad spines; a pair of mental and a pair of post- 
mental barbels Aspredinichthys. 

bb. Breast and head not margined with tentacles. Maxillary barbel adnate. 

d. Maxillary barbel with a smaller barblet near its base Aspredo. 

dd. Maxillary without a barblet at its base Platystacus. 

aa. Tail short, vent nearly equidistant from tip of snout and base of caudal. Anal with 11 rays or fewer. 
( BunocephalincB.) 
e. Dorsal well-developed, of five rays, the last of which is adnate. Barbels six. 

/. Head depressed, its greatest depth about half its width; coracoid and coracoid processes not 
prominent; no prominent tentacles about head; humeral process extending past cora- 
coid process Bunocephalus. 

//. Head about as deep as wide; coracoid and coracoid processes prominent; head externally 
tuberculate; coracoid process extending past humeral process Agmus. 

Subfamily Aspredinina. 
Chamaigenes 3 gen. nov. 
Chamaigenes Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
380 (name only). 
» xatmiyevriSj earth-born. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 121 

Type, Aspredo filamentosus Cuvier and Valenciennes. 

Distinguished by the marginal tentacles of the head and breast, and by the 
absence of prominent hooks on the ethmoid. Nasals each with a hook, which 
is partially concealed. A single pair of mental barbels. 

3. Chamaigenes filamentosus (Cuvier and Valenciennes). 

Aspredo filamentosus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 
437, pi. 450 (Cayenne). — Gunther, Catalogue, V, 1864, 270 (Demerara).— 
Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 26. 

Platystacus filamentosus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 

II, 1889, 50; Occasional Papers Cal. Acad. Sci., I, 1890, 24. 
Chamaigenes filamentosus Eigenmanx, Eepts. Princeton Univ. Exp. Patagonia, 

III, 1910, 380. 

Several specimens; largest about 215 mm. Georgetown. (C. M. Cat. No. 
1553a-e; I. U. Cat. No. 11971.) 

Distance from tip of snout to dorsal plate about 4.5 in the length to base of 
caudal; depth of head about half its width, which is almost equal to its length 
to upper angle of gill-openings. A. 51-56; D. 5; last ray adnate for half its length, 
the first ray extremely elongate, considerably longer than its distance from the 
tip of the snout in the adult. 

Eye small, about one-fourth the interorbital; maxillary barbel reaching gill- 
opening or pectoral, scarcely adnate; patches of teeth of the two premaxillaries 
forming a single band; width of mouth about one-third the width of the head; 
a small barbel on the maxillary barbel opposite the corner of the mouth; a series 
of barbels directly back of it past the base of the pectoral; a pair of post-mental 
barbels, corresponding in position to the post-mentals in tibicen; no mental barbels. 

A round pectoral pore under the tip of the humeral process; pectoral spine 
with hooks on its inner margin, increasing in size toward the tip; those of the 
outer margin small, directed at right angles to the spine. 

Chocolate, without blotches; lower surface plain; a dark streak back from eye. 
Anterior part of anal hyaline; ventrals dusky, other fins blackish. 

Aspredinichthys Bleeker. 
Aspredinichthys Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 118 (tibicen). 

Type, Aspredo tibicen Temminck. 

Readily distinguished by the four nasal spines and the marginal tentacles of 
the head and breast. 



122 MEMOIRS OF THE CARNEGIE MUSEUM 

4. Aspredinichthys tibicen (Tcmminck). 
Aspredo tibicen (Temminck) Cuvier and Valenciennes Hist. Nat. Poiss., XV, 
1840, 438 (Surinam). — Muller and Troschel, in Schomburgk, Reisen, III, 
1848, 630 (coast of Guiana) .— Gunther, Catalogue, V, 1864, 270 (British 
Guiana). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 26. 
Platystacus tibicen Eigenmann and Eigenmann, Proc. Cal. Acad. ScL, (2), II, 
1889, 50; Occasional Papers Cal. Acad. Sci., I, 1890, 24 (Caruca; RioMuria). 
Aspredinichthys tibicen Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 118. — Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 381. 
Large series of individuals up to a length of almost 215 mm. from the George- 
town market. Evidently the most abundant of the banjomans. (C. M. Cat. No. 
1552a-o; I. U. Cat. No. 11970.) 

Distance from snout to dorsal plate nearly 5 in the length to the caudal; 
width of head about equal to its length to the upper angle of the gill-opening; 
depth of head about half its width; D. 5, the last ray adnate, the first much pro- 
longed, its length in the adult equal to its distance from the eye or longer, not much 
produced in the young. A. 51-58, the last ray adnate. 

Head pointed, width of mouth one-third width of head, snout produced be- 
yond the mouth for about one-third the width of the latter; eye rather large, 
almost half the width of the interorbital; maxillary barbels about reaching gill- 
openings, adnate for about one-fourth their length; maxillary barbel with a barbel 
opposite the corner of the mouth; a series of barbels behind it on the lower surface 
of the head and breast to about the base of the pectoral. A pair of mental barbels 
nearly equidistant from each other and from the mouth, not reaching the post-mental 
barbels, which are nearly twice as far apart; lower surface of head warty; a round 
pectoral pore below the tip of the humeral process; inner margin of pectorals with 
spines increasing toward the tip, those of the outer margin pointed toward its tip. 
Slaty, irregularly marked with squarish darker blotches on the back; ventrals 
and anterior part of anal hyaline, other fins slate or blue-black. 

I examined two specimens of this species in the Museum at Leiden from 

Surinam. 

Aspredo Bleeker. 

Aspredo (ex Linnseus, Mus. Adolphi Fred., 1754, 73) Bleeker, Nederl. Tijdschr. 

Dierk., I, 1863, 117 {batrachiis) . 

Type, Aspredo batrachus Gronow = Aspredo aspredo (Linnseus). 

Distinguished by the absence of marginal tentacles on the head and breast 
and by having a basal barblet on the maxillary. Snout without hooks. 

Two species, distinguished thus: 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 123 

Key to the Species of Aspredo. 

a. Head to tip of nuchal plate more than 4 in the length to base of caudal aspredo. 

na. Head to tip of nuchal plate 4 or less in the length to the caudal sicuephorus. 

5. Aspredo aspredo (Linnaeus). 
Silurus aspredo Linn^us, Syst. Nat., ed. 10., 1758, 304; ed. 12, 1766, 502.— Bonna- 

terre, Tabl. Enc. Ichth., 178S, 150.— Lacepede, Hist. Nat. Poiss., V, 1803, 78. 
Platystacus aspredo Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 

1889, 50 (Para; Arary); Occasional Papers Cal. Acad. Sci., I, 1890, 23. 
Aspredo aspredo Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

380; Proc. U. S. Nat. Mus., XIV, 1891, 26. 
Platystacus Icevis Bloch, Ausl. Fische, VIII, 1794, 58. — Bloch and Schneider, Syst. 

Ichth., 1801, 373. 
Aspredo Icevis Muller and Troschel, in Schomburgk, Reisen, III, 1848, 630 

(Waini). 
Aspredo batrachus (ex Linnseus, Mus. Adolphi Fred., 1754, 73) Gronow, Cat. Fish, 

ed. Gray, 1854, 137. — Bleeker, " Silures de Suriname," 1864, 93 (Surinam). — 

Gunther, Catalogue, V, 1864, 268, part (British Guiana; Cayenne; Surinam). 

No specimens of this species were secured. It has been recorded from Guiana 
by Muller and Troschel and by Gunther. 

Head greatly depressed, spatulate; interorbital width 3.5 in the distance from 
base of pectoral to tip of snout. Mouth broad, the snout projecting almost its 
entire length; each jaw with two patches of small teeth. Maxillary barbel reach- 
ing to base of pectoral, an accessory barbel in front; mental barbel placed near 
the lip, extending to the post-mental, which is equal to the interorbital. Coracoid 
processes slightly diverging backward, the length equal to the space between them. 
A minute pectoral pore at the extremity of the coracoid process. Humeral process 
a little longer than the coracoid process and overlapping it. 

Distance of dorsal fin from tip of snout 3.8 in the length; first dorsal ray rarely 
prolonged. Outermost caudal rays slightly produced. Pectoral spine as in A. 
tibicen. Dorsal surface uniform purplish brown, the ventral surface plain light, 
shading into light purple or pinkish; dorsal fin dusky, usually with a dusky median 
stripe on the interradial membrane; caudal dark, except the outermost rays; pec- 
torals smutty, ventrals usually white, the posterior half sometimes dusky; anal fin 
white anteriorly, becoming dusky backward; maxillary barbels more or less dusky. 
Greatest width before pectoral fins 5.66-6 in the length; A. 51-55. 

In the specimens recorded by Cuvier and Valenciennes as Icevis the head is 4 
or less than 4 in the length to the tip of the caudal. 



124 MEMOIRS OF THE CARNEGIE MUSEUM 

6. Aspredo sicuephorus Cuvier and Valenciennes. (Plate I, fig. 1.) 
Aspredo sicuephorus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 439 

(Mana). — Gunther, Catalogue, V, 1864, 269 (copied). — Eigenmann, Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 380. 
Platystacus sicuephorus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 

1889, 50; Occasional Papers Cal. Acad. Sci., I, 1890, 24 (Curuca; Rio 

Muria). 
Aspredo Icevis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 431 (Guiana). 
Aspredo batrachus Gunther, Catalogue, V, 1864, 269, part. 

Abundant in the brackish water about Georgetown. The largest of the 
Aspredinidse secured. 

Many specimens, the largest 340 mm. No young were secured. (C. M. Cat. 
No. 1551a-e; I. U. Cat. No. 11969.) 

Distance from snout to predorsal plate 4 to tip or to base of caudal; width of 
head equal to its length to upper angle of gill-opening, its depth little more than 
a fourth of its width; D. 5, the last ray adnate. A. 54-57, the last ray adnate. 

Eye minute; maxillary barbel adnate for nearly half its length, reaching the 
pectoral spine, a small barbel near its base reaching the mental barbel, the latter 
to the post-mental, the three in a nearly straight line, the mental barbel just behind 
the angle of the mouth; patches of teeth on the two premaxillaries separate in the 
middle; mouth broad, half the width of the head; the snout projecting beyond 
the mouth for half the width of the latter; first dorsal ray more or less prolonged; 
pectoral spine heavy, with nearly straight teeth on its inner margin, teeth on its 
outer margin smaller, pointed toward the tip of the spine; no axillary pore. 

Uniform light brown to slate above, ventral and anterior part of anal hyaline; 
anal and caudal dark. 

I have also examined the specimens in the Leiden and the British Museums. 
It is very probable that aspredo and sicuephorus are identical. Giinther's specimens 
"e" and three of " a-d" are sicuephorus, while one has the head more than 4 in 
the length and represents aspredo. 

Platystacus Bloch. 
Platystacus Bloch, Ausl. Fische, VIII, 1794, 52 (sp.). — Bleeker, Nederl. Tijdschr- 

Dierk., I, 1863, 118. 

Type, Platystacus cotylephorus Bloch. 

Sternal and abdominal region without tentacles; maxillary barbel simple, 
without tributary barbels at its base; snout without spines. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 125 

7. Platystacus cotylephorus Bloch. 
Platystacus cotylephorus Bloch, Ausl. Fische, VIII, 1794, 54, pi. 372. — Bloch and 

Schneider, Syst. Ichth., 1801, 372. — Bleeker, " Siluresde Suriname," 1864, 

95 (Surinam). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 

1889, 50 (Vigia; Para; Tajapuru); Occasional Papers Cal. Acad. Sci., I, 1890, 

21 (Vigia; Para; Tajapuru). — Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 300. 
Silurus cotylephorus Lacepede, Hist. Nat. Poiss., V, 1803, 78. 
Aspredo cotylephorus Gunther, Catalogue, V, 1864, 269 (Surinam). 
Silurus hexadayctlus Lacepede, Hist. Nat. Poiss., V, 1803, 82. 
Aspredo sex-cirrhis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840,441. 
Aspredo spectrum Gronow, Cat. Fish, ed. Gray, 1854, 137. 

I did not observe this species myself, but several specimens were taken by 
Mr. Ellis. 

A. 53-57; greatest width, before pectoral spine, 5.5-6.5 in the length; length 
of head to gill-opening 9 in the length, with the caudal fin. 

Head greatly depressed, narrowed forward; interorbital width 3.5 in the dis- 
tance from base of pectoral to tip of snout; width of mouth equals the interorbital 
plus the orbits, the snout projecting half its length. Premaxillaries with two rhom- 
boidal patches of villiform teeth, lower jaw with wider patches of similar teeth. 
Maxillary barbels reaching to gill-opening, mental not to post-mental barbels, which 
are as long as or a little longer than the width of the mouth. Coracoid processes 
slightly diverging backward, the length of the processes 1.25 in the distance be- 
tween their bases. Humeral processes co-extensive with but not overlapping the 
coracoid processes. Pectoral pore below the tip of humeral process. 

Distance of dorsal fin from tip of snout 3.5-3.75 in the length; first dorsal ray 
scarcely prolonged. Outermost caudal rays prolonged. Four rows of papillae on 
the sides. Dark brown, blotched with lighter. 

Subfamily Bunocephalin^e. 

Bunocephalus Kner. 

Bunocephalus Kner, SB. Akad. Wiss. Wien, XVII, 1855, 95. — Bleeker, Nederl. 

Tijdschr. Dierk., I, 1863, 118 (verrucosus). 

Type, Platystacus verrucosus Bloch. 

Tail short; dorsal well-developed; barbels 6; head depressed, without prom- 
inent knobs. 

Key to the Species of Bunocephalus. 

a. A. 6; distance from snout to dorsal 2.75-3 in the length with the eaudal ; width 3.5 in the 
length gronovii. 



126 MEMOIRS OF THE CARNEGIE MUSEUM 

aa. A. 7; distance from snout to dorsal considerably more than 3 in the length with caudal; width more 

than 3 in the length; general color dark chocolate amaurus. 

aaa. A. 8 or 9, rarely 7; distance from snout to dorsal more than 3 in the length with the caudal; width less 
than 3 in the length; general appearance sand-like chamaizelus. 

8. Bunocephalus gronovii Bleeker. (Plate I, figs. 2-2a.) 
Aspredo verrucosa Gronow, Cat. Fish, ed. Gray, 1854, 137 (not of Bloch). 
Bunocephalus verrucosus Kner., SB. Akad. Wiss. Wien., XVIII, 1855, 96 (Barra do 

Rio Negro). 
Bunocephalus gronovii Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 329 (based on 
Gronow, Mus. Ichth., II, 1756, 5, No. 153, pi. 5, fig.3). — Gunther, Cata- 
logue, V, 1864, 266 (Demerara). — Eigenmann and Eigenmann, Proc. Cal. 
Acad. Sci., (2), II, 1889, 48; Occasional Papers Cal. Acad. Sci., I, 1890, 17 — 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 380. 
The following description by Gunther is based on a specimen (figs. 2-2a), 102 
mm. long collected by Hancock. The distance between the end of the snout and 
the origin of the dorsal fin is one-third, or nearly one-third, of the total length 
(with the caudal fin) ; the length of the head to the gill-opening is rather more than 
one-seventh. Upper jaw but little prominent. The maxillary barbel extends to 
the third fifth of the pectoral; the dorsal is inserted nearer to the end of the snout 
than to the root of the caudal. Hind portion of the tail as high as broad. Brown 
ish, clouded and spotted with darker. 

Head to gill-opening 5 in the length; greatest width 3.5; distance of dorsal 
from tip of snout 2.25; caudal 4; D. 5; A. 6. 

9. Bunocephalus amaurus sp. nov. (Plate I, fig. 2.) 
Bunocephalus amaurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 380 (name only). 

Type, 69 mm. Konawaruk. (Carnegie Museum Catalog of Fishes No. 
1555.) 

Cotype, 53 mm. Konawaruk. (I. U. Cat. No. 11973.) 

Head to gill-opening 5.66 in the length; greatest width 3.5; distance of dorsal 
from tip of snout 2.33 in the length; caudal nearly 5. D. 5; A. 7; depth of 
head 1.5 in distance from pectoral to tip of snout; length of coracoid process about 
equal to the distance between their bases; anterior margin of coracoid with an 
externally perceptible crest. Head verrucose but without knobs; nuchal crest 
prominent, a notch between it and the knobbed dorsal plate. 

Maxillary barbels reaching pectoral; pectorals not quite to ventrals; humeral 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



127 




process reaching last fourth of the pectoral spine; half of the last dorsal ray adnate; 
caudal peduncle terete; everywhere tuberculate, nine conspicuous series of tubercles 
on the tail. 

Dark chocolate, a light saddle between the dorsal and nuchal crest; back be- 
hind the dorsal with lighter blotches; dorsal, caudal, and anal fins black, their 
margins white, first rays of dorsal and anal 
and outer rays of caudal banded; ventrals 
mottled, margined with white, darkest just 
below the light edge; pectorals black, last 
rays with light mottlings; barbels banded. 

10. Bunocephalus chamaizelus sp. nov. 
(Plate II, fig. 1.) 
Bunocephalus chamaizelus Eigenmann, Repts. 

Princeton Univ. Exp. Patagonia, III, 

1910, 380 (name only). 

Type, 36 mm. Erukin. (Carnegie Mu- 
seum Catalog of Fishes No. 1556.) 

Cotypes, five specimens, 24-44 mm. 
Erukin. (C. M. Cat. No. 1557a and 6; I. 
U. Cat. No. 11974.) 

Cotypes, seven specimens, 34-39 mm 
and b; I. U. Cat. No. 11975.) 

Cotypes, six specimens, 30-37 mm. Gluck Island 
and b; I. U. Cat. No. 11976.) 

Head to gill-opening 5 in the length; greatest width 3.16; distance of dorsal 
from snout 2.36 in the length; caudal 4.4-6; D. 5; A. 8 or 9, rarely 7; depth of 
head about 1.5 in distance of pectoral from tip of snout; length of coracoid process 
about one-half the distance between its bases; anterior margin of coracoid without 
an externally visible crest; caudal peduncle terete; everywhere tuberculate, the 
regular rows of the tail somewhat obscured by the intervening tubercles; tubercles 
on the head variously developed. 

A faint ridge from eye to occiput; occipital with a slight knob, nuchal plate 
with two, dorsal plate with one, the four in a straight line. 

Maxillary barbel reaching pectorals; pectorals to ventrals in the smaller speci- 
mens; humeral process reaching third fifth of pectoral spine. 

Lighter or darker sand-color; a dark streak from pectoral forward to mouth 



Fig. 24. Bunocephalus amaurus Eigen- 
mann. Type. C. M. Cat. No. 1555. 

Tumatumari. (C. M. Cat. No. 1558a 
(C. M. Cat. No. 1559a 



128 



MEMOIRS OF THE CARNEGIE MUSEUM 



or chin, sometimes expanded downward behind gill-opening; a more or less evident 
dark streak across the nuchal plate ; a conspicuous dark band across the back and 
dorsal fin, extending forward below to the axil; one or two more or less evident 
dark blotches on the back of the tail, the anterior over the anal; fins colored like 
the adjoining portions of the body. 

Agmus 4 gen. nov. 
Agmus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 379. 

Type, Agmus scabriceps Eigenmann and Eigenmann (Plate IV). 

This genus differs from Bunocephalus in the great development of tubercles 
about the head, which at the occiput is almost as high as it is wide; the depth of the 
head at this point equals the distance of the pectoral from the snout. This genus 
reaches the limit of divergence from Aspredo. 

11. Agmus lyriformis sp. nov. (Plate III.) 
Agmus hjriformis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
379 (name only). 

Type, 56 mm. Gluck Island. (Carnegie Museum Catalog of Fishes No. 
1554.) 

Cotype, 49 mm. Rupununi. (I. U. Cat. No. 11972.) 

The only other species of the genus is 
A. scabriceps Eigenmann and Eigenmann 
from Jutahy, differing from lyriformis in its 
converging coracoid processes, mottled fins, 
and extremely tubercular head. 

Head to end of occipital process 2.66 
in its length ; depth of head at occipital pro- 
cess about equal to its width at gill-open- 
ings. D. 5; A. 6. 

Nuchal plate with two high knobs; 
dorsal plate with two small knobs, one on 
either side in front of the dorsal; a trans- 
verse ridge in front of the nuchal crest, 
curved backward on the sides and ending 
in a small knob; a knob over each eye, con- 
tinued backward as a low crest with a small 
knob near its middle and a larger one in front of the large occipital knob, the two 




Fig. 25. 
Type. C. M 



Agmus hjriformis Eigenmann. 
Cat. No. 1554. 



4 dynbs, a craggy place. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 129 

orbital knobs connected by a low ridge, forming a lyre-shaped figure with the 
crests extending backward from the orbital knobs, which approach each other be- 
hind; low crests extending forward from the orbital knob and meeting on the 
snout, each with a small knob forward of the eye; humeral process extending to 
the middle of the pectoral spine, a small knob on the sides above and behind its 
tip; coracoid process extending to the last fifth of the pectoral spine, but slightly 
converging behind; a transverse ridge joining the bases of the processes, the cora- 
coid outlined by another ridge. 

Maxillary barbels extending slightly beyond base of pectoral; mental barbels 
not reaching post-mentals, post-mentals not equal to interorbital. 

Body and head everywhere covered with warts, those on the tail in longitudinal 
series, those along the lateral line longest. 

Dark chocolate, mottled, some of the warts light; first rays of dorsal, anal, 
ventrals, and pectoral banded, the rest of these fins black, margined with white. 
Outer rays of the rounded caudal banded, the rest of the fin black, except the 
extreme tips of the rays, which are white; barbels banded with black and white. 

Ventrals in the cotype mottled. 

Family III. SILURID^. 

"Skin-fishes." 
Characters as given in the key, page 119. 

Key to the Genera of Silurid^e. 
a. Gill-membranes free from the isthmus. Or the nares approximate in Arius. 
b. Nares approximate, the posterior with a valve (Ariince). 

c. Mental barbels two; maxillary barbel broad, band-like. Pectoral spine, and usually the 

dorsal spine, with long band-like filaments Felichthys. 

cc. Mental barbels four. Palatine teeth fixed. Head and occipital process covered with very 
thin skin, granular. 

'/. Posterior nostrils connected by a membrane Selenaspis. 

■Id. Posterior nostrils not connected by a membrane. 

e. Palatine patches of teeth with a backward projecting angle on the inner margin. 
/. Dorsal plate enlarged, the occipital process correspondingly reduced. 

Sciadeichthys. 
//. Dorsal plate small, crescent-shaped. Occipital process linear or leaf-shaped. 

Notarius. 
ee. Palatine patches of teeth without a backward projecting angle. Eye above the 
level of the mouth; gill-rakers twenty-five or fewer. 
h. Teeth on palate granular; no teeth on vomer; gill-membranes united, a narrow 

membrane free Arius. 

hh. Teeth on palate villiform, vomer with or without teeth Hexanematichthys. 



130 MEMOIRS OF THE CARNEGIE MUSEUM 

bb. Nares remote; barbels six; adipose fin well-developed. 

i. Teeth incisor-like, in two series in the upper, in a single series in the lower jaw. First dorsal 

and pectoral rays not spine-like; adipose long (Callophysina?) Callophysis. 

ii. Teeth villiform, in bands ( Pimelodinas.) 

j. Vomer without teeth or with teeth in minute patches. 

k. Snout broad and produced, spatulate. Adipose short. First ray of the dorsal and 
pectoral fins articulate, not pungent, prolonged in filaments; barbels flat, 

not fringed Megalonema. 

kk. Adipose fin very long, barbels flat, ribbon-like; dorsal and pectoral spines not 

pungent, the dorsal spine produced Pinirampus. 

kkk. Snout not produced, barbels not flat. 
I. Orbit without a free margin. 

m. Dorsal and pectoral spines strong, pungent; body short. 

n. Dorsal surface of skull covered with thin skin; head about as broad 
as long; origin of ventrals behind middle of body, except 
sometimes in the young; sometimes a small circular fontanel 
at base of occipital process; frontal fontanel not extending 
backward behind the eye. 
o. Premaxillary patch of teeth with a backward projecting angle. 

Pseudopimelodus. 

oo. Occipital crest very short, not nearly reaching dorsal; premaxillary 

teeth without a backward projecting angle on the sides. 

Species with a light band across the occiput. . . Microglanis. 

nn. Dorsal surface of skull covered with a thick layer of muscle; occipital 

crest short ; origin of ventrals in front of middle. . . Brachyglanis. 

mm. Pectoral spines strong but short; dorsal spines small or replaced by a 

soft ray; skull covered with a thick layer of muscle; anal 17-21, 

body long, slender; occipital crest short. 5 

p. Caudal rounded; an occipital, no frontal fontanel; ventrals under 

posterior half of dorsal Leptoglanis. 

pp. Caudal forked; ventrals under posterior half of dorsal; a median 
ridge from the frontal fontanel to the occipital process; caudal 
without accessory rays, lower caudal lobe longer; adipose 

reaching caudal Myoglanis. 6 

mmm. No dorsal or pectoral spines; upper surface of head covered with the 

skin only; fontanel a narrow slit continued to base of occipital 

process; ventrals entirely under the dorsal or partly in front of it. 

much nearer snout than to caudal, body long and slender. 

q. Caudal rounded Heptapterus.' 

5 Skull covered with thin skin; A. 9. Imparfinis. 

6 It is probable that Heptapterus colletti Steindachner "with the ventrals under the origin of the 
dorsal; upper caudal lobe longer; caudal with fulcra; adipose not reaching caudal" should be the type of 
another genus. 

7 The genus Heptapterus Bleeker, so far as known with certainty, is confined to southeastern tropical 
America. It consists of the following species: Heptapterus mustelinus Valenciennes, from Rio Grande 
do Sul and the lower La Plata, and Heptapterus eigenmanni Steindachner, from Maldonado. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 131 

qq. Caudal forked. 

r. Anal of eighteen or more rays Acentronichthys. 8 

rr. Anal of about eleven rays. Premaxillary band of teeth with a 

backward projecting angle Chasmocranus. 

II. Orbit with a free margin. Head distinctly longer than broad, 
s. Occipital process not reaching the dorsal plate. 

t. Fontanel not continued behind the eye; a small pit or fontanel some- 
times at the base of the occipital process Rhamdia- 

tt. Fontanel continued to base of occipital process. A dorsal and a 

pectoral spine Rhamdella.' 

ss. Occipital process reaching the dorsal plate; adipose fin longer than high. 
u. Occipital process narrow; fontanel to base of occipital process; 

humeral process spine-like Pimelodella. 

uu. Occipital process tapering; fontanel not continued behind the eyes; 
humeral process broad, not spine-like. 

v. Caudal deeply forked Pimelodus. 

vv. Caudal obliquely rounded Gceldiella. 

jj. Teeth on vomer in moderate or large patches. 
w. Barbels not band-like. 

.r. Head as broad as long. D. 1,7. Upper surface of head with vermiculating 
ridges. Vomerine patch of teeth large, pentagonal, contiguous to the 
palatine patches. Occipital process large, semicircular, not meeting 
the reniform dorsal plate, upper half of the adipose fin usually rayed. 

Phractocephalus. 

xx. Head longer than broad; inner surface of gill-covers usually with one or more 

dermal pouches. D. 1,6-8. Caudal forked or rounded. 

y. Inner teeth of the upper jaw slender and freely movable, the band scarcely 

narrowed in the middle; teeth on vomer and palatines much smaller, 

(the palatine teeth smaller than those on the vomer), villiform. 

Adipose fin equal to or longer than the anal fin; caudal deeply 

forked, the lobes pointed Brachyplatystoma. 

yy. Teeth all similar in the upper jaw and on the vomer. 

2. Head narrowed forward, its width at the mouth scarcely if any more 
than two-thirds its greatest width; adipose fin longer than the 
anal; lower jaw produced beyond upper Hemisorubim. 

8 The genus Acentronichthys Eigenmann and Eigenmann contains with certainty but one species, 
the type, Acentronichthys leptos Eigenmann and Eigenmann. Heplaplerus sxirinamcnsis Bleeker may 
belong to this genus. It is certain that the Heptapterus collettii placed here by Eigenmann and Eigenmann 
is not an Acentronichthys, for it has a strong pectoral spine. 

An examination of the type of Heptapterus surinamensis in Leiden gives the following: 

Skull covered with thin skin, fontanel a narrow slit to base of occipital process; first dorsal ray 

just like the second, not spinous; last ventral ray and third dorsal ray about equidistant from the tip 

of the snout; A. 18; caudal with numerous accessory rays, especially on the ventral side; middle rays 

radiating, all broken, probably rounded; teeth on each pre-maxillary in a band one-half wider than deep. 

It is therefore a Heptapterus if the caudal was rounded or an Acentronichthys if it was forked. 

9 No dorsal spine; first pectoral ray spinous at its base only; upper caudal lobe longer. Rhamdia- 
glanis of southeastern Brazil. 



132 MEMOIRS OF THE CARNEGIE MUSEUM 

zz. Head depressed, its width at the mouth about equal to its greatest 
width. Adipose fin shorter than the anal; caudal forked, the 
rays much branched. Maxillary band of teeth much narrowed 
in the middle; teeth on the vomer separated on the median 
line, closely joined to the palatine patches, together forming, 
on either side, a figure somewhat like a comma. Top of head 
osseous; the occipital process produced, meeting or nearly 
meeting the dorsal plate; fontanel extending from the middle 
of the snout to behind the eyes, and continued to the occipital as 

a groove Pseudoplatystoma. 

aa. Gill-membranes united and joined to the isthmus; nares remote, without barbels. 
A. A series of bony plates along the sides. (Doradince.) 

B. Eye small, in anterior portion of head; snout depressed; teeth well-developed; humeral 
process much longer and stronger than the coracoid process; anterior nares near the 

upper lip Doras. 

BB. Eye in middle or behind the middle of the head. 

C. Barbels all simple, teeth none Oxydoras. 

CC. Maxillary and mental barbels fringed. 

D. Teeth none; a single large pectoral pore Leptodoras. 

DD. Teeth in one or both jaws; numerous pectoral pores Hemidoras. 

A A. No plates along the sides. 

E. Maxillary and mental barbels present. (Auchenipterinm.) 

F. Mental barbels in two pairs. Adipose fin shorter than the anal fin. 

G. Anal short, 7-11; mouth terminal; jaws equal; caudal forked; V. 6. . . Centromochlus. 
GG. Anal 19-41. 

//. Caudal obliquely truncate or slightly emarginate; outer margin of pectoral 
spine serrate; mouth terminal, jaws equal or the lower longer; no promi- 
nent bony orbit. V. 6-10, A. 19-40 Trachycorystes. 

HH. Caudal deeply forked; outer margin of pectoral spine smooth or granular. 

V. 8; A. 17-21 Pseudauchenipterus. 

FF. Mental barbels arranged in a series near the symphysis; adipose fin short; dorsal fin 

well-developed, 1,6. Teeth villiform. V. 12-15 Auchenipterus. 

EE. Maxillary barbels only. (Ageneiosince.) 

I. Air-bladder projecting into the abdominal cavity, naked laterally, the skin over it 
forming a large pseudo-tympanum; snout short, about equal to the eye. 

Tympanopleura. 

//. Air-bladder minute, concealed under peritoneum and largely covered with bone; no 

pseudo-tympanum. Snout much longer than eye Ageneiosus. 

Subfamily Ariinje. 
Felichthys Swainson. 10 

10 A specimen of Felichthys 295 mm. long marked filamentosus is in the Leiden Museum, from Ind. 
Occid., probably collected by Schomburgk. 

Dorsal from snout 3 in the length; highest anal ray 6+ in the length, base of anal 7; pectoral 
spine 4 in the length, dorsal spine 4.S; anal lobe with numerous black dots; A. 19; distance of adipose 
from dorsal 2.6 in the length. This specimen would therefore be bahiensis. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 133 

Gaff-topsail Catfishes. 
Breviceps Swainson, Class. Fishes, Amph., and Rept., I, 1838, 328 (bayre). 
Felichthys Swainson, Class. Fishes Amph., and Rept., II, 1839, 305, substitute 

for Breviceps Swainson, preoccupied (bagre). 
Ailurichthys Baird and Girard, Proc. Acad. Nat. Sci. Phila., 1854, 26 (marinus). 
Mlurichthys Gill, Proc. Acad. Nat. Sci. Phila., 1863, 172, emendation. 
Mystus Gronow, Cat. Fish, ed. Gray, 1854, 165 (carolinensis), name preoccupied. 
Pimelodus Bleeker, " Silures de Suriname," 1864, 65 (bagre), not of Lacepede, as 

restricted by Gill. 

Nostrils close together, separated by a valve; lower jaw with only two barbels, 
band-like; dorsal and pectoral spines prolonged into filaments. 

Key to the Species of Felichthys. 
a. Distance of dorsal fin from tip of snout 3.33 in the length; distance of adipose from the dorsal fin 2.6 
times in the length, or longer; base of anal 4.66 in the length, or longer. Anterior lobe of anal 
with minute dots; highest anal ray less than half the length of the base of the anal; vomerine and 

palatine patches of teeth separate; anal rays 32-35 bagre. 

aa. Distance of dorsal from tip of snout 3 in the length; distance of adipose from dorsal fin 3 in the 
length; highest anal ray about as high as the base of the anal, which is 5.8-6.5 in the length; anal 
rays 20-24 marinus. 

12. Felichthys bagre (Linnaeus). 

Silurus bagre Linnaeus, Syst. Nat., ed. 12, I, 1766, 505. — Gmelin, Syst. Nat., I, 

iii, 1788, 1360. 
Pimelodus bagre Lacepede, Hist. Nat. Poiss., V, 1803,93, 98 (Brazil). — Bleeker, 

" Silures de Suriname," 1864. 66 (Surinam)". 
Mlurichthys bagre Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Ailurichthys bagre Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 148 (Sao Matheos; Santos; Para; Curuca; Bahia; Pernambuco; Brit. 

Guiana); Occasional Papers Cal. Acad. Sci., I, 1890, 33. 
Felichthys bagre Gill, Proc. U. S. Nat. Mus., XIII, 1891, 354. — Jordan and Ever- 

mann, Bull. U. S. Nat. Mus. No. 47, I, 1896, 116. 
Galeichthys gronovii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 40 

(Guiana; Maracaibo; Mana; Cayenne; Bahia). — Muller and Troschel, in 

Schomburgk, Reisen, III, 1848, 628 (Waini and Barima). — Kner, SB. Akad. 

Wiss. Wien, XXVI, 1857, 392 (Cajutuba; Para). 
Mlurichthys gronovii Gunther, Catalogue, V, 1864, 178 (Demerara; West Indies). 
Galeichthys eidouxii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 43 

(Guayaquil). 



134 MEMOIRS OF THE CARNEGIE MUSEUM 

Mlurichthys eydouxii Jordan, Proc. U. S. Nat. Mus., VII, 1884, 40 (note on type). 
Bagrus macronemus Ranzani, Nov. Com. Acad. Sci. Inst. Bonon., V, 1842, 334, 

pi. 28 (Brazil). 
Mystus carolinensis Gronow, Cat. Fish, ed. Gray, 1854, 156. 
Pimelodus longifilis " Mus. L. B." (fide Bleeker). 

Eight specimens, 194-354 mm. Georgetown market. (C. M. Cat. No. 1270, 

1271; I. U. Cat. No. 11773.) 

With the characters given in the key. 

13. Felichthys marinus (Mitchill). 

Silurus marinus Mitchill, Trans. Lit. and Philos. Soc. N. Y., I, 1814, 433. 

Galeichthys marinus DeKay, Nat. Hist. New York, Zoology, IV, 1842, 178, pi. 37, 
fig. 118 (New York). 

Ailurichthys marinus Baird and Girard, Proc. Acad. Nat. Sci. Phila., 1854, 26. — 
Girard, U. S. and Mex. Boundary Survey, II, 1859, 31, pi. 14 (Indianola, 
Tex.). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 148 
(Rio de Janeiro; Para; Bay of Balaxy; Mobile Bay; Pernambuco; Victoria); 
Occasional Papers Cal. Acad. Sci., I, 1890, 36. 

jElurichthys marinus Gunther, Catalogue, V, 1864, 178 (North America). — 
Goode, Proc. U. S. Nat. Mus., II, 1879, 119 (St. Johns River, Florida) .— Stein- 
dachner, " Flussfische Siidamerika's," i, 1879, 10 (Orinoco near Ciudad Boli- 
var). — Jordan and Gilbert, Proc. U. S. Nat. Mus., V, 1882, 246 (abun- 
dant from Pensacola, Florida, to Galveston, Texas), 584 (Charleston, S. C). — 
Jordan, Proc. U. S. Nat. Mus., VI, 1883, 106 (Key West, Florida) .—Jordan 
and Gilbert, Synopsis Fishes N. Am., 1883, 111 (Cape Cod to Mexico). — 
Jordan, Cat. Fishes N. Am., 1885, 16 (name only); Proc. U. S. Nat. Mus., IX, 
1886, 26 (Beaufort, N. C). 

Felichthys marinus Gill, Proc. U. S. Nat. Mus., XIII, 1891, 354. — Jordan and 
Evermann, Bull. U. S. Nat. Mus. No. 47, I, 1896, 118. 

Galeichthys parrce Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 33 
(New York; Charlestown; New Orleans; Rio Janeiro). — Castelnau, Anim. Am. 
Sud, Poiss., 1855, 37 (Bahia). — Hyrtl, Denkschr. Akad. Wiss. Wien, XVI, 
1859, 17 (vertebra? 13 + 7 + 30). 

Several specimens, Georgetown market. (C. M. Cat. No. 1484.) 
With the distinguishing characters given in the key. 

Sciadeichthys Bleeker. 
Sciades Muller and Troschel, Horae Ichth., Ill, 1849, 8 (emphysetus et pictus). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 135 

Sdadeichthys Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 62, 66 {emphysetus), 

not Sciadeichthys Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 99. 

Type, Bagrus emphysetus Muller and Troschel. 

This genus is distinguished from other South American Silurids by the approxi- 
mate nares, the enlarged dorsal plate, the backward projecting angle of the palatine 
patches of teeth, and the absence of an internarial membrane. The species are 
indiscriminately called " gillbacker." 

Only four species were secured, but several others found at Cayenne may 
occur occasionally or seasonally in Guiana. 

Key to the Species of Sciadeichthys. 
a. Teeth on the palate villiform or bluntly conical. 

6. Dorsal plate pointed in front, entering the notched occipital process. 

c. Eye 8 in interorbital; dorsal plate as wide as the cranium behind the eye; granulations not 

extending forward to eyes flavescens. 

cc. Eye 4 in interorbital; dorsal plate much narrower than the cranium behind the eye, its sur- 
face striate; maxillary barbel reaching past origin of ventrals emphysetus. 

66. Dorsal plate notched in front, receiving the point of the occipital process. Eye nearer snout 
than to preopercle; jaws subequal; occipital process broader than long, mucronate at tip. 

Eye 1.25 in snout proops. 

aa. Teeth on the palate granular parkeri. 

14. Sciadeichthys flavescens (Cuvier and Valenciennes). (Plate V, fig. 1.) 
Bagrus flavescens Cuvier and Valenciennes, Hist. Nat. Poiss., XIV, 1839, 462 

(Cayenne).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 386 (locality ?). 
Arius flavescens Gunther, Catalogue, V, 1864, 151 (copied). 
Galeichthys flavescens Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus flavescens Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 141 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 53. 
Sciadeichthys flavescens Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 

1896, 123. 

The head of a specimen of this species was secured in the Georgetown market. 
It measures 305 mm. to the dorsal. (C. M. Cat. No. 1265.) 

15. Sciadeichthys emphysetus (Muller and Troschel). (Plate IX, fig. 1.) 

Bagrus (Sciades) emphysetus Muller and Troschel, Horse Ichth., Ill, 1849, 8 
(Surinam). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 627 
(Waini and Barima). 

Arius emphysetus Gunther, Catalogue, V, 1864, 150 (copied). 

Sciades emphysetus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 91 (name only). 



13G MEMOIRS OF THE CARNEGIE MUSEUM 

Galeichthys emphysetus Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559. 
Tachisurus emphysetus, Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 144; Occasional Papers Cal. Acad. Sci., I, 1891, 53. 
Arius physacanthus Vaillant, Bull. Mus., d'Hist. Nat., V, 1899, 155; Nouv. Arch. 

Mus. d'Hist. Nat., (4), II, 1900, 128, pi. 7, fig. 1-lc (French Guiana). 

I have examined the type of emphysetus in the Berlin Museum and five speci- 
mens, 250-500 mm., Georgetown market. (C. M. Cat. No. 1487, 1735, 2486; 
I. U. Cat. No. 12110.) I have not been able to find any specimens in the Berlin 
Museum from Guiana. The type from Surinam is undoubtedly identical with the 
specimens described below and with Vaillant's physacanthus. 

Head 3.8; depth 5.75; D. I, 7; A. 17 or 18; adipose fin 9.5 in the length; eye 3 
in the snout, 4 in the interorbital, 10 in the head. 

Head depressed forward, the snout broad; width of the head at the rictus equal 
to the greatest depth; dorsal plate shield-shaped, its pointed anterior end fitting 
into the notched occipital process, its width 1.3 in the width of the skull behind the 
eyes; occipital process about half as wide as broad; surface of dorsal plate pitted; 
occipital process with rows of nodules, the median row being most prominent; 
skull striate to in front of eye; maxillary barbels reaching past base of ventrals; 
outer mental barbel to middle of pectoral. Teeth all small, those of the roof of 
the mouth in four contiguous patches, the palatine patches large, subcircular. 

Basal half or more of the dorsal spine swollen, its length equal to the width of 
the head at the eyes or the opercle; anterior half of the swollen part of the dorsal 
spine tuberculate, the part beyond with recurved notches both in front and behind; 
pectoral spine about equal to the dorsal spine, the outer margin tuberculate to 
near the tip, where it is notched, the posterior surface serrate; caudal deeply 
forked, the upper lobe longer, 4 in the length; anal emarginate. 

Bluish gray above, white below; tips of dorsal, pectorals, ventrals and anterior 
part of anal dusky. 

16. Sciadeichthys proops (Cuvier and Valenciennes). (Plate V, fig. 2; 

Plate VI, figs. 1-3.) 
Bagrus proops Cuvier and Valenciennes, Hist. Nat. Poiss., XIV, 1839, 457 
(Antilles; Guiana; Surinam; Porto Rico). — Muller and Troschel, in Schom- 
burgk, Reisen, III, 1848, 627 (Waini and Barima). — Kner, SB. Akad. Wiss. 
Wien, XXVI, 1857, 386 (locality ?). 
Arius proops Gunther, Catalogue, V, 1864, 148 (copied). 

Netuma proops Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 67; " Silures de Suri- 
name," 1864, 62, pi. 7, pi. 12, fig. 2 (Surinam). 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 137 

Galeichthys proops Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus proops Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 

141 (Pernambuco) ; Occasional Papers Cal. Acad. Sci., I, 1890, 57. 
Sciadeichthys proops Jordan and Evermann, Bull. U. 8. Nat. Mus. No. 47, I, 

1896, 123. 

Several specimens, 245-680 mm. Georgetown market. (C. M. Cat. No. 
1263, 1264, 1280; I. U. Cat. No. 11774.) 

I have also examined the specimens in the Leiden and Berlin Museums men- 
tioned in the synonymy. 

Head 4-4.33; depth 7; D. 1,7; A. 18. Eye 1.25-1.5 in snout, 5.5-8 in head, 
1.75-2.66 in the interorbital. 

Slender and elongate, broader than deep. Head depressed, its width 1.33 in 
its length, its depth 2, width at mouth 2; anterior portion of the head flat above; 
top of the head, humeral process, and dorsal plate coarsely granular, the granules 
arranged in series along the fontanel. Occipital process mucronate, broader than 
long; dorsal plate large, butterfly-shaped. Opercle striate; fontanel 1.5 times as 
long as the eye, its center in front of the middle of the eye, continued as a shallow 
groove. 

Jaws subequal; teeth all villiform, the intermaxillary band very wide and 
shallow; teeth on the roof of the mouth in six contiguous patches. 

Gill-membranes meeting in an angle, forming a broad fold across the isthmus. 
Gill-rakers 5 + 10. Pectoral pore large; vertical series of pores present. 

Distance of dorsal spine from snout 2.8 in the length; the dorsal spine granular 
in front, striate on the sides, weakly serrate behind, its length 1.25-1.5 in the head. 
Space between dorsal and adipose fins 2.75-3 in the length, the adipose fin little 
shorter than the dorsal, the posterior margin free. Caudal deeply forked, its upper 
lobe longer, 4-4.5 in the length. Anal emarginate, as high as long, 2-2.33 in the 
head. Ventrals 2 in the head. Pectoral spine rough or granular in front, serrate 
behind, 1.2-1.33 in the head. 

Plumbeous above, with blue lustre, white below; maxillary barbels dark, the 
mental barbels white; fins all more or less dotted with brown. 

Abundant at Georgetown. The skull is prepared and sold in souvenir stores 
as the "Crucifix Fish." 

17. Sciadeichthys parked (Traill). (Plate V, fig. 3.) 
Silurus parkeri Traill, Mem. Wern. Soc, VI, 1832, 377, pi. 6, fig. 1 (muddy 
water of rivers of Guiana). — Schomburgk, Fishes Brit. Guiana, I, 1843, 
188 (Guiana). 



138 MEMOIRS OF THE CARNEGIE MUSEUM 

Arius parkeri Gunther, Catalogue, V, 1864, 153 (copied). 

Galeichthys parkeri Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 

Tachisurus parkeri Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 

141 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 65. 
Selenaspis parkeri Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 1896, 

123. 
Arius guadriscutis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

111 (Cayenne; Mana).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 389 

(Para). 
Netuma quadriscutis Bleeker, "Silures de Suriname," 1864, 59, pi. 8, pi. 13, fig. 2 

(Surinam). 

Several specimens, 238-408 mm. Georgetown market. (C. M. Cat. No. 
1272-1279; I. U. Cat. No. 11775.) 

I have also examined the specimen of quadriscutis mentioned by Bleeker. 

Head 3.6; depth 5.33-5.5; D. 1,7; A. 15-18. 

Body comparatively stout, the greatest width equaling the greatest depth. 
Head large, flatfish above; profile descending; width of head 1.17 in its length; 
width at the mouth 2-2.4, its depth at the base of the occipital process scarcely 
less than its greatest width. Top of head coarsely granular in young, the granules 
becoming finer and more regularly arranged in the adult; opercles smooth; humeral 
process with radiating lines of granules. Dorsal plate large, emarginate in front, 
receiving the pointed occipital process. Middle of the fontanel above the posterior 
margin of the eye. No skinny flap connecting the posterior nostrils. 

Maxillary barbels extending little beyond the base of the pectoral or shorter; 
mental barbels short. Teeth in jaws coarse, conical, those on the palate and 
vomer finely granular, the patches separate in the young, but united and covering 
most of roof of mouth in the adult. Gill-membranes forming a broad marginal 
flap across the isthmus. Gill-rakers 3^1 + 7-9. 

Distance of dorsal from tip of snout 2.33 in the length; the spine 1.33-1.6 
in the head, granular in front, serrate behind. Distance of adipose fin from the 
dorsal 4-4.5 in the length, the adipose fin twice as long as high, adnate, as long 
as the dorsal fin. 

Caudal forked, the upper lobe longer, 4.33-4.5 in the length. Anal fin about 
as long as high, 2.15-2.25 in the head. Ventrals 1.75-2 in the head. 

Pectoral spine stout, 1.25-1.16 in the head, granular in front (serrate in young), 
striate on sides, serrate along inner margin. 

Yellow in life. The most abundant catfish of the Georgetown market. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 139 

Selenaspis Bleeker. 
Selenaspis Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 62 (herzbergii) . 
Leptarius Gill, Proc. Acad. Nat. Sci. Phila., 1863, 170 (dowii). 

Type, Silurus herzbergii Bloch. 

This genus is distinguished from Sciadeiehthys by the internarial membrane. 
The character is scarcely of generic importance, especially since in the young of 
S. proops a slit or incipient membrane is often present between the posterior nares. 

Two species are found on the Atlantic coast of America, and a third one on 
the Pacific coast of Panama. 

Key to the Species of Selenaspis. 
a. Upper jaw distinctly longer than lower; snout 3.5 in the head; palatine teeth forming a U-shaped 

figure herzbergii. 

aa. Upper jaw distinctly shorter than the lower; snout about 7 in the head; palatine teeth forming a 
transverse patch without backward projecting angles passany. 

18. Selenaspis herzbergi (Bloch). (Plate VII, fig. 1.) 
Silurus herzbergii Bloch, Ausl. Fische, VIII, 1794, 33, pi. 367 (Surinam). — Bloch 

and Schneider, Syst. Ichth., 1801, 383 (Surinam). 
Bagrus herzbergii Cuvier and Valenciennes, Hist. Nat. Poiss., XIV, 1839, 453 

(Mana; Cayenne).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 386 (Para). 
Selenaspis herzbergii Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 63. — Jordan and 

Evermann, Bull. U. S. Nat. Mus. No. 47, 1, 1896, 125. — Eigenmann and Bean, 

Proc. IT. S. Nat, Mus., XXXI, 1907, 659 (Amazon). 
Arius herzbergii Gunther, Catalogue, V, 1864, T44 (British Guiana; Demerara).— 

Vaillant, Nouv. Arch. Mus. d'Hist. Nat,, (4), II, 1900, 124 (Mahury, French 

Guiana). 
Netuma herzbergii Bleeker, " Silures de Suriname", 1864, 61, pi. 9, pi. 13, fig. 3, 

(Surinam). 
Galeichthys herzbergii Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus herzbergii Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 141 (Para; Curuca; Bahia); Occasional Papers Cal. Acad. Sci., I, 

1890, 59. 
Pimelodus argenteus Lacepede, Hist. Nat. Poiss., V, 1801, 94, 102. 
Bagrus pemecus Cuvier and Valenciennes, Hist. Nat. Poiss., XIV, 1839, 456 

(Cayenne) . 
Bagrus mesops Cuvier and Valenciennes, Hist. Nat, Poiss., XIV, 1839, 456.— 

Muller and Troschel, in Schomburgk, Reisen, III, 1848, 627 (Waini and 



140 MEMOIRS OF THE CARNEGIE MUSEUM 

Barima).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 384, pi. 1, fig. 2 (Para). 
Arius mesops Gunther, Catalogue, V, 1864, 145 (copied). 
Galeichthys mesops Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus mesops Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 

141 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 57. 
Sciadeichthys mesops Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 

1896, 123. 
Bagrus coelestinus Muller and Troschel, Horse Ichth., Ill, 1849, 7 (Guiana).— 

Muller and Troschel, in Schomburgk, Reisen, III, 1848, 627 (Waini and 

Barima) . 
Hexanematichthys hymenorhinus Bleeker, Versl. en Med. Akad. Wet. Amsterdam, 

XIV, 1862,377 (Surinam); " Silures de Suriname," 1864, 57, pi. 11, fig. 2, 

pi. 13, fig. 4 (Surinam). 
Netuma dubia Bleeker, Versl. en Med. Akad. Wet. Amsterdam, XIV, 1862, 382 

(Surinam); ''Silures de Suriname," 1864, 63, pi. 15, fig. 2, pi. 13, fig. 5 

(Surinam). 
Arius dubius Gunther, Catalogue, V, 1864, 144 (copied). 
Galeichthys dubius Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus dubius Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 141 (name only). 

Many specimens, 230-335 mm. Georgetown market. (C. M. Cat. No. 1266- 
1269; I. U. Cat. No. 11776.) 

Several specimens, to 197 mm. Mahaica. (C. M. Cat. No. 1733). 

Head 3.66-3.75; depth 5-6; D. 1,7; A. 18. Eye 1.75-2.5 in snout, 2.33-4 in 
interorbital, 5.5-8 in head. 

Elongate, the width equal to or greater than the depth. Width of the head 
1.25-1.33 in its length, at the angle of the mouth about 2; its depth 1.66-1.75 in its 
length. Humeral process, dorsal plate, and top of head to between the eyes, granular. 
Occipital process wider than long, scarcely keeled. Fontanel not continued behind 
the eyes and without backward projecting groove. Posterior nares connected by a 
membrane. 

Barbels flattish, those of the maxillary reaching to near the ventrals (to middle 
of pectorals in older individuals) ; post-mental to or beyond base of pectoral, mental 
to gill-opening. Teeth villiform, vomerine and palatine patches of about equal 
size and shape in the young, a separate patch behind the palatines being developed 
sooner or later. The teeth of the palate differ more than in any other species. 

Gill-membranes meeting in an angle, forming a fold across the isthmus. Gill- 
rakers 6 + 10. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 141 

Distance of dorsal spine from snout 2.5-2.75 in the length; dorsal and pectoral 
spines subterete, the outer margin roughened, the sides striate; the dorsal spine 
slightly serrate behind, a little shorter than the pectoral spine, 1.4-1.6 in the head; 
pectoral spine strongly serrate behind. Space between the dorsal and adipose fins 
3.6-4 in the length. Adipose fin as long as the dorsal. Upper caudal lobe the 
longer, about 4 in the length. Anal as high as long, 2 in head. Ventral 1.6-2 in 
head. Pectoral pore minute; sides with vertical series of pores. Plumbeous above, 
silvery on sides, fins dusky. 

I have examined the types of coelestinus, hymenorhinus, dubius, and mesops. 
They are all identical with herzbergi. 

In the types of Bagrus coelestinus Miiller and Troschel in the Berlin Museum, 
215-275 mm. long, from Guiana, there is a distinct but narrow streak between the 
posterior nostrils. The teeth are just as in a specimen of herzbergi 270 mm., col- 
lected by me. 

The mesops of Miiller and Troschel, about 320 mm., is like coelestinus, but 
the posterior patches of teeth are not so highly developed as in the latter. 




Fig. 26. Teeth of Selenaspis herzbergi (Bloch). Total length of specimens the teeth of which are fig- 
ured in order from left to right: 140 mm.; 240 mm.; 300 mm. , 

Three specimens of herzbergi, hymenorhinus, and dubius, 255, 207, and 170 mm. 
long, in the Leiden Museum, have the dorsal aspect of the head alike, and the maxil- 
lary barbels extend respectively not quite to the end of the pectoral, to the ventral, 
and a little beyond the origin of the ventral. The internasal membrane is most devel- 
oped in the largest and least in the smallest specimen. In the second in size the 
posterior palatine patches are not developed, corresponding with a specimen 210 
mm. long collected by me and now in the Berlin Museum. In the smallest the 
two palatine patches are close together and the posterior patches much larger in 
proportion. 

19. Selenaspis passany (Cuvier and Valenciennes). (Plate VII, fig. 2.) 
Bagrus passany Cuvier and Valenciennes, Hist. Nat. Poiss., XIV, 1839, 458 
(Cayenne). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 627 
(Waini and Barima). 



142 



MEMOIRS OF THE CARNEGIE MUSEUM 



Arius passany Gunther, Catalogue, V, 1864, 149 (copied). 

Galeichthys passany Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 

Tachisurus passany Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 141; Occasional Papers Cal. Acad. Sci., I, 1890, 58. 

I have examined the specimen about 543 mm. long collected by R. Schomburgk 
and now in the Berlin Museum, No. 2968. 

It is very similar to herzbergii but can easily be distinguished by its short snout 
or rather abbreviated upper jaw and the peculiar dentation of the palate. 




Fig. 27. Teeth of Selenaspis -passany (Cuvier and Valenciennes). 

Not arius Gill. 
Arius Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 91 (grandicassis) , not Arius 

Bleeker, 1858. 
Notarius Gill, Proc. Acad. Nat. Sci. Phila., 1863, 171 (grandicassis). 

Type, Arius grandicassis Cuvier and Valenciennes. 

Distinguished by its peculiar and variable occipital crest. Dorsal plate small ; 
occipital crest not wider, usually much narrower at its base than towards its 
middle or tip. 

But three species of this genus are known. They range along the coast of 
South America from near Bahia to Guiana. All three are abundant in the George- 
town market. 

Key to the Species of Notarius. 

a. Occipital process narrowly and deeply constricted at base, its margins regularly and strongly convex. 

grandicassis. 
aa. Occipital process broadly and deeply constricted, its margins describing a double curve; convex 

toward tip, concave toward base parmocassis. 

aaa. Occipital process narrowed, its margins scarcely convex stricticassis. 

20. Notarius grandicassis (Cuvier and Valenciennes). (Plate VIII, fig. 1.) 
Arius grandicassis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 54, pi. 

427 (Guiana?).— Gunther, Catalogue, V, 1864, 153 (copied). 
Galeichthys grandicassis Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name 

only) . 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 143 

Tachisurus grandicassis Eigenmann and Eigenmann, Proc. Cal. Acad. ScL, (2), I, 
1888, 141 (Maranhao; Bahia) ; Occasional Papers Cal. Acad. Sci., I, 1890, 65. 

Netuma grandicassis Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 
1896, 126. 
Several specimens, 335-490 mm. Georgetown market. (C. M. Cat. No. 

1254-1259; I. U. Cat. No. 11777.) 




Fig. 28. Outlines of occipital processes of various individuals of Notarius grandicassis (Cuvier and 
Valenciennes). Total length of specimens the processes of which are figured in order from left to right: 
335 mm.; 435 mm.; 400 mm.; 490 mm. 

Head 3.4-3.75; depth 5.66-6; D. 1,7; A. 18. Eye 3-3.5 in snout, 4-4.5 in 
interorbital, 8.5-10 in head. 

Body cylindrical in front, tapering to a slender caudal penduncle. Head greatly 
depressed, profile almost straight, descending, the width of the head 1.33-1.4 in 
its length, its depth 1.8-2 in its length. Occipital process with a deep constriction 
where it joins the occiput, shaped like a clover leaflet, much longer than broad, 
sometimes keeled. Center of the fontanel over the middle of eye, the fontanel 
not continued backward as a groove. Occipital process, top of head, and humeral 
process granular; interorbital region with four ridges, the inner ones bounding the 
fontanel, the outer ones running obliquely backward from near the posterior nares. 

Maxillary barbels reaching to the base of the pectorals, mentals to gill-opening, 
post-mentals a little longer. 

Upper jaw projecting a diameter of the eye or more, the lip very wide, espe- 
cially in front, making the nose pointed; teeth of both jaws rather large, those on 
the palate somewhat smaller; the depth of the premaxillary band 7-9 in its 
width; the mandibulary band very shallow; vomerine teeth present in adult ; pala- 
tine patches triangular, produced backward; four patches in adult, the two additional 
ones placed just back of the two triangular ones in front. 

Gill-membranes meeting in an angle, forming a fold across the isthmus. Gill- 
rakers 6 + 10. 

Distance of dorsal spine from snout 2.33-2.5 in the length. Distance of 
adipose fin from the dorsal 3.6-4 in the length; adipose fin at least as long as the 



144 



MEMOIRS OF THE CARNEGIE MUSEUM 



dorsal fin, adnate. Caudal fin forked, the upper lobe longer, about 5 in the length. 
Anal fin longer than high. Ventrals small. Pectoral pore large. 
Light brown above, somewhat smutty below. 

21. Notarius parmocassis (Cuvier and Valenciennes). (Plate VIII, fig. 2.) 
Arius parmocassis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 57 

(Bahia). — Gunther, Catalogue, V, 1864, 154 (copied). 
Tachisurus grandicassis parmocassis Eigenmann and Eigenmann, Proc. Cal. Acad. 

Sci., (2), I, 1888, 141 (Bahia; San Matheos; Maranhao); Occasional Papers 

Cal. Acad. Sci., I, 1890, 68. 
Netuma stricticassis Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 

1896, 126, part. 





Fig. 29. Outlines of occipital processes of various individuals of Notarius parmocassis (Cuvier 
and Valenciennes). Total length of specimens the processes of which are figured in order from left to 
right: 376 mm.; 418 mm.; 480 mm.; 435 mm.; 375 mm.; 232 mm. 



Several specimens, 232-480 mm. Georgetown market. (C. M. Cat. No. 
1250-1253; I. U. Cat. No. 11779.) 

This species differs from grandicassis in having the occipital process separated 
from the occiput by a broader constriction and the process more elongate-ovate. 

Vomerine teeth are present in the adult. No patches of teeth are found back 
of the two triangular palatine patches. 

22. Notarius stricticassis (Cuvier and Valenciennes). (Plate VIII, fig. 3.) 
Arius stricticassis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 58 

(Cayenne). — Gunther, Catalogue, V, 1864, 154 (copied). — Bleeker, " Silures 

de Suriname," 1864, 55, pi. 5, pi. 12, fig. 4 (Surinam). 
Tachisurus grandicassis stricticassis Eigenmann and Eigenmann, Proc. Cal. Acad. 

Sci., (2), I, 1888, 141 (Bahia; Maranhao); Occasional Papers Cal. Acad. Sci., I, 

1890, 68. 
Netuma stricticassis Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 

1896, 126. 

Several specimens, 280-405 mm. Georgetown market. (C. M. Cat. No. 
1260-1262; I. U. Cat. No. 11778.) 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 14.") 

I have also examined the specimens in the Leiden Museum. 

This species differs from Notarius parmocassis in having the occipital process 
still narrower, the margins being little convex. No teeth on vomer; no patches 
behind the two triangular palatine patches. 




Fig. 30. Outlines of occipital processes of three specimens of Notarius stricticassis (Cuvier and 
Valenciennes). Total length of specimens the processes of which are figured in order from left to right: 
280 mm.; 400 mm.; 405 mm. 

Arius Cuvier and Valenciennes. 
Arius Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 53. — Bleeker, 

Ichth. Arch. Ind. Prodr., I, 1858, 62, 67 (arius). 

Type, Pimelodus arius Buchanan. 

Palatine patches of teeth without a backward projecting angle; teeth of the 
palate granular, none on the vomer; gill-membranes united to the isthmus, with a 
very narrow free margin across the latter. 

23. Arius spixi (Agassiz). 11 (Plate IX, fig. 2.) 

Pimelodus abidus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pi. 7, fig. 1 (Equa- 
torial Brazil). 

Pimelodus spixii Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 19. 

Arius spixii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 76 (copied). 

Tachisurus spixii Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 
146 (Maranhao; Bahia; Rio Janeiro; Para; Santos in Sao Paulo; Abrolhos); 
Occasional Papers Cal. Acad. Sci., I, 1890, 88. — Jordan and Evermann, Bull. 
U. S. Nat. Mus. No. 47, I, 1896, 131. 

Arius arenatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 106 (Cay- 
enne). — Gunther, Catalogue, V, 1864, 172 (copied). — Bleeker, " Silures de 
Suriname," 1864, 53, pi. 4, fig. 2 (Surinam). 

Galeichthys arenatus Jordan, Proc. U. S. Nat. Mus., IX, 1886, 558 (name only). 

Arius nuchalis Gunther, Catalogue, V, 1864, 171 (British Guiana). 

Galeichthys nuchalis Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 

11 Two specimens of fissus from Cayenne (from the Paris Museum) and one from Surinam (all in 
the museum at Leiden) have head 3.4 and 3.6 in the length; otherwise they are very similar to the specimens 
of arenatus ( = spixi) with head 3.9 in the length. The palatine patches of teeth are also smaller. 



146 MEMOIRS OF THE CARNEGIE MUSEUM 

Tachisurus nuchalis Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 

145 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 86. — Jordan and 

Evermann, Bull. U. S. Nat. Mus. No. 47, I, 1896, 131. 

There is no doubt that the specimens recorded below are identical with the 
nuchalis of Giinther, the types of which I have examined. Whether or not they 
are identical with spixi is not quite so certain. 

Several specimens, 128-235 mm. Georgetown market. (C. M. Cat. No. 
1287a-c; I. U. Cat. No. 11781.) 

Several specimens, 140 mm. Mahaica. (C. M. Cat. No. 1732.) 

Head 3.6-4; depth 5-5.5; D. 1,7; A. 21. Eye 1.5-2 in the snout, 5-6.5 in the 
head, 2.75-3 in the interocular. 

Body compressed, especially towards the caudal fin, the depth greater than 
the width. Head narrowed forward, its greatest width 1 .33 in its length, its greatest 
depth 1.5; width at the mouth 2.2 in the length of the head. Top of the head 
granular in the young, the granules becoming more or less united in the adult, 
forming fine reticulating ridges, especially on the occipital process; occipital process 
longer than broad, with a blunt median ridge, the margins concave. Fontanel 
narrowing without interruptions, continued as a deep tapering groove to near the 
base of the occipital process; interorbital area with four ridges; opercles and hu- 
meral process rough, covered with skin; sides of the head and snout with reticulating 
mucous canals. 

Maxillary barbels varying in extent, from about the middle of the pectoral 
to the base of the ventrals; post-mental barbels extending to base of pectoral or 
to near its tip; mentals to edge of gill-membrane or to beyond base of pectoral. 

Upper jaw projecting; lips more or less papillose; teeth on the premaxillary 
and the outer ones of the mandible villiform; the inner series of the mandible 
and the palate granular; the palatine patches of teeth small, subovate, sometimes 
contiguous in front. 

Gill-membranes united, joined to the isthmus, a very narrow free margin 
across it. Gill-rakers 6 + 11-13. Pectoral pore moderate. 

Distance of dorsal spine from snout 2.33-2.64 in the length; the spines 1.2-1.5 
in the head, serrated on its inner margin, granular or almost smooth on its outer 
margin. Distance of adipose from the dorsal fin 3.2-3.6 in the length, the adipose 
fin shorter than the dorsal fin, free posteriorly. Caudal forked, the upper lobe 
slightly the longer, 4-5 in the length. Anal fin scarcely longer than high, its highest 
ray about 2 in the head. Ventral fin 1.66-2 in the head. Pectoral spine strong, 
about as long as the dorsal spine, serrate on its inner margin, granular or scarcely 
roughened on the outer margin. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 147 

Color brownish above; sides and ventral surface silvery, sometimes with brown 

dots. 

Hexanematichthys Bleeker. 

Hexanematichthys Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 62, 65. 

Type, Bagrus sondaicus Cuvier and Valenciennes. 

Similar to Arius, but the palatine teeth villiform. The species are found largely 
on the Pacific Coast. But one species has been taken in British Guiana. 

24. Hexanematichthys rugispinis (Cuvier and Valenciennes). (Plate IX, fig. 3.) 

Arius rugispinis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 77 

(Cayenne).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 388 (Para).— Gun- 

ther, Catalogue, V, 1864, 156 (copied). — Vaillant, Nouv. Arch. Mus. 

d'Hist. Nat., (4), II, 1900, 124 (Carsevenne, French Guiana). 
Galeichthys rugispinis Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 
Tachisurus rugispinis Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 145 (Para); Occasional Papers Cal. Acad. Sci., I, 1890, 83. 

Several specimens, 235-420 mm. Georgetown market. (C. M. Cat. No. 
1281-1286; I. U. Cat. No. 11780.) 

Head 3.5-4; depth 5.5-6; D. I, 7; A. 19-21. Eye 3 in snout; 3.5 in inter- 
orbital, 10 in head. Slender, tail compressed. Head broad and depressed, tapering 
forward; width of the head 1.5-1.4 in its length, at the angle of the mouth 2.4-2.5; 
depth of head 1.6-2; profile rather steep. Top of head, humeral process, front 
and sides of the spines, and dorsal plate granular, the granulation not extending 
forward to above middle of cheeks. Occipital process triangular, about as long 
as broad, the median ridge not very prominent. Middle of the fontanel behind the 
eye, the posterior portion separated by a bridge, not continued backward as a 
groove; interorbital region with four ridges. 

Barbels villiform; maxillary barbel reaching to or beyond base of pectoral, 
post-mental to gill-opening, mental barbels much shorter. 

Mouth inferior, lower jaw included, lips thick; teeth villiform, the anterior 
ones in the jaws longer, depth of the premaxillary band 4 in its width; palatine 
patches of teeth one diameter of the eye apart, the width of the patches less than 
one diameter of the eye. 

Gill-membranes meeting in an angle, forming a fold across the isthmus. Gill- 
rakers 6 + 11. Pectoral pore none; vertical series of pores present. 

Distance of dorsal spine from the snout 2.33-2.5 in the length. Space between 
dorsal and adipose fins 4-4.66 in the length. Adipose fin adnate, as long as the anal 
fin. Ventrals 2.5 in the head; pectoral spine serrate behind. 



148 MEMOIRS OF THE CARNEGIE MUSEUM 

Subfamily Callophysin^e. 
Callophysus Miiller and Troschel. 

Callophysus Miiller and Troschel, Horse Ichth., Ill, 1849, 1 (sp.). — Bleekeh, 

Nederl. Tijdschr. Dierk,, I, 1863, 101 (macropterus). 
Pimelotropis Gill, Proc. Acad. Nat. Sci. Phila., 1859, 196 (lateralis = macropterus) . 
Pseudocallophysus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 102 (ctenodus = 

macropterus) . 

Type, Pimelodus macropterus Lichtenstein. 

One series of teeth in the lower jaw, two series in the upper; dorsal and pectoral, 
without spines; adipose long. A single species. 

25. Callophysus macropterus (Lichtenstein). 

Pimelodus macropterus Lichtenstein, Wiedem. Zool. Mag., I, iii, 1819, 59 (Brazil). 

Callophysus macropterus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 
629 (Essequibo); Horse Ichth., Ill, 1849, 1 (Brazil; Guiana). — Gunther, Cata- 
logue, V, 1864, 137 (copied).— Peters, MB. Akad. Wiss. Berlin, 1877, 470 
(Apure). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 120 
(Obidos; Lake Jose Assu; Cameta; Rio Negro; Santarem; Tonantins; Mana- 
capuru); Occasional Papers Cal. Acad. Sci., I, 1890,95. — Eigenmann and 
Bean, Proc. IT. S. Nat. Mus., XXXI, 1907, 659 (Amazon).— Eigenmann, 
Repts. Princeton Univ. Exp. Patagonia, III, 1910, 382. 

Pimelodus ctenodus Agassiz, Gen. et Spec. Pise. Bras., 1829, 21, plate 8a (Equa- 
torial Brazil). — Cuvter and Valenciennes, Hist. Nat. Poiss., XV, 1840, 186 
(copied). — Castelnau, Anim. Am. Sud, Poiss., 1855, 35 (Amazon). 

Callophysus ctenodus Muller and Troschel, Horse Ichth., Ill, 1849, 2 (Brazil). — 
? Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 422 (locality?).— Gunther, Cata- 
logue, V, 1864, 137 (copied). 

Pimelodus instants Schomburgk, Fishes Brit. Guiana, I, 1841, pi. 6 (not descr.). 

Pimelotropis lateralis Gill, Proc. Acad. Nat. Sci. Phila., 1859, 196 (Amazon). 

Callophysus lateralis Gunther, Catalogue, V, 1864, 136 (copied). — Steindachner, 
"Ichthyologische Beitriige," v, 1876, 105 (Santarem; Tabatinga; Montalegre; 
Obidos; Rio Negro; Tonantins; Lake Manacapuru; Jose Assu). — Cope, 
Proc. Am. Philos. Soc, XVII, 1878, 676 (Peruvian Amazon). — Vaillant, Bull. 
Soc. Philom., (7), IV, 1880— (Calderon). 
No specimens were secured. I have examined the specimen collected by 

Schomburgk and now in Berlin. 



EIGKNMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 149 

Head 4-4.66; depth 5-6; Br. 8-9; D. 7; A. 12; eye 3-4 in the snout, 2-3 
in the interorbital, 7-8 in the head. 

Barbels flat, those of the maxillary reaching to the end of the adipose or beyond. 
Color uniform light brown, or with spots on the sides and adipose. 

Subfamily Pimelodin^e. 
Pinirampus Bleeker. 
Pinirampus Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 198 (pirinampu). 
Pirinampus Gunther, Catalogue, V, 1864, 135. 
Type, Pimelodus pirinampu Spix. 

Barbels broad, flat with a membranous border behind; first dorsal and pec- 
toral rays articulate, not pungent; adipose fin much longer than the anal fin; no 
teeth on the vomer. A single species. 

26. Pinirampus pirinampu (Spix). 
"Mairipak." 

Pimelodus pirinampu Spix, Gen. et Spec. Pise. Bras., 1829, 20, pi. 8 (Brazil). — 
Schomburgk, Fishes Brit. Guiana, I, 1841, 183 (Guiana) .— Castelnau, Anim. 
Am. Sud, Poiss., 1855, 35 (Amazon). 

Pinirampus pirinampu Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 
1888, 121 (Cameta); Occasional Papers Cal. Acad. Sci., I, 1890, 104.— Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 383. 

Pimelodus pirinampus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 196 
(Brazil).— ?Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 416 (locality?). 

? Pimelodus barbancho Humboldt, Rec. Obs. Zool., II, 1833, 172 (Venezuela). 

Pinirampus typus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 100 (name only). 

Pirinampus typus Gunther, Catalogue, V, 1864, 135 (copied). 

A single specimen of this species 770 mm. long from the falls of the Mazaruni 

was secured for me by Mr. Fowler, Commissioner of Lands and Mines. (C. M. 

Cat. No. 2490.) 

Head 4.66, depth about 6; D. 1,6; A. 11; eye 5.5 in the snout (3.5 in young), 

10.75 in the head (7.5 in young), 5 in the interorbital (2.5 in young); adipose 2.2 

in the length. 

Head depressed, snout parabolic, body sub terete, slightly compressed above; 

caudal peduncle subterete. First dorsal ray prolonged, longer than the head. 

Pectoral spine equal to the head in length, not prolonged; adipose dorsal beginning 

near middle of last dorsal ray; maxillary barbel extending to end of ventrals. 
Steel blue above, white below. 



150 MEMOIRS OF THE CARNEGIE MUSEUM 

Megalonema gen. nov. 

Megalonema Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 383 

(name only). 

Type, Megalonema platycephalum sp. nov. 

Pimelodines without teeth on vomer, the pectoral and dorsal spines prolonged 
into filaments, articulate, not pungent; barbels flattened, not fringed; premaxillary 
band of teeth without backward projecting angles; occipital process narrow, not 
reaching dorsal plate; caudal deeply forked; eye in middle of head. 

27. Megalonema platycephalum sp. nov. (Plate X, fig. 2.) 
Megalonema platycephalum Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 383 (name only). 

Type, 173 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 
1684a.) 

Cotypes, four specimens, 37-65 mm. Tumatumari. (C. M. Cat. No. 1685a; 
I. U. Cat. No. 12060.) 

Head 3.66; depth 5.5, D. 1,6; A. 11; eye 2 in snout, 5 in head, equal to 
interorbital. 

Triangular in section at the dorsal, becoming oval at the caudal peduncle; 
profile nearly straight descending to the snout, ventral profile straight. 




Fig. 31. Outline of premaxillary band of teeth in Megalonema platycephalum Eigenmann. 

Head rounded at the occiput, flat between the eyes; occipital process spine- 
like, not quite reaching the dorsal plate; a pair of ridges from in front of the max- 
illary barbels converging to the base of the occipital process; fontanel not continued 
to the posterior margin of the eye; upper jaw projecting the width of the premax- 
illary band of teeth; snout broad, depressed, width of mouth equals half the length 
of the head; width of premaxillary band of teeth 7 in the length of its outer margin, 
its outer ends rounded. 

Maxillary barbel reaching tip of anal; outer mental barbel reaching tip of inner 
pectoral ray; the mental barbels some distance in advance of the outer or post- 
mentals, reaching base of pectorals; gill-membranes broadly overlapping, separate 
to below the angle of the mouth. 

Dorsal spine slender, articulate above, as long as the head, the rays decreasing 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 151 

in height, the second extending past the tip of the last; space between the dorsals 
6.5 in the length, base of adipose 4.25; caudal lobes slender, longer than head, the 
middle rays about one-third the length of the lobes; anal emarginate, the anterior 
rays extending past the tip of the last; ventrals not reaching anal; pectoral to 
ventrals. 

Straw-color in alcohol ; a pair of hidden spots at the base of the caudal, lower 
lobe dusky. 

In the specimen 65 mm. long the first pectoral ray is enormously prolonged, 
reaching past origin of the anal; first dorsal ray to the adipose; in the younger 
specimens they are shorter. In the young there is a faint lateral streak, an area along 
the base of the anal and along the middle of the back, four streaks on the snout, 
one from mouth up to base of maxillary barbel and then back to eye, and a pair 
along the middle of the snout, diverging in front and behind. 

Pseudopimelodus Bleeker. 

Pseudopimelodus Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 196, 207 (sp.); Nederl. 

Tijdschr. Dierk., I, 1863, 101 (raninus). 
Batrachoglanis Gill, Ann. Lye. Nat. Hist. N. Y., VI., 1858, 389. 

Type, Pimelodus raninus Cuvier and Valenciennes. 

Distinguished from Microglanis by the backward projecting angles in the 
premaxillary patches of teeth. 

In 1890 I identified Pimelodus bufonius with the Pimelodus zungaro of Hum- 
boldt. Humboldt's species is known only from his figure and description, which 
are said to have been taken from a fish three feet four inches long and reported 
to attain seven feet. It is very doubtful whether the zungaro of Eigenmann and 
Eigenmann from Goyaz is identical with Humboldt's species. It is also very 
doubtful whether Pimelodus mangurus Valenciennes from the La Plata is syn- 
onymous with zungaro. This elimination of synonyms leaves the genus Pseudo- 
pimelodus, as here understood, consisting of raninus Cuvier and Valenciennes 
(the type), bufonius Cuvier and Valenciennes, acanthocheira Eigenmann and 
Eigenmann, cottoides Boulenger, and the two species here described. 

Key to the Species of Pseudopimelodus. 

a. Occipital crest not meeting the dorsal plate; dorsal, caudal and ventrals in adult spotted, the latter 
two not margined with white; dorsal with a median or submedian light bar on the last rays, its 
margin sometimes white; no humeral spine, pectoral teeth not as wide as the spine .. villosus. 
aa. Occipital crest meeting the dorsal plate; a humeral spine. 

b. Teeth on anterior margin of the pectoral spine as wide as the spine or wider. 



152 MEMOIRS OF THE CARNEGIE MUSEUM 

c. Nape usually without a distinct light band; dorsal, caudal, anal and ventrals edged with 
white. 
d. Maxillary barbels not quite reaching gill-opening; dorsal spine rough on both edges. 

albomarginatus. 

dd. Maxillary barbels reaching a little beyond tip of humeral process raninus. 

(cc. Nape with a zigzag cross-band; anal margined with white acanthochira. 

66. Teeth on anterior margin of the pectoral less than half the width of the spine cottoides and 

bufonius.) 

28. Pseudopimelodus villosus sp. nov. (Plate X, fig. 1.) 

? Pimelodus raninus (not of Cuvier and Valenciennes) Muller and Troschel, 

in Schomburgk, Reisen, III, 1848, 628 (all rivers). 
Pimelodus (Pseudopimelodus) raninus Peters, MB. Akad. Wiss. Berlin, 1877, 470 

(Apure). 
Pseudopimelodus villosus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 384 (name only). 

Type, 148 mm. Potaro Landing. (Carnegie Museum Catalog of Fishes 
No. 1677.) 

Cotypes, two specimens, 148 and 142 mm. Potaro Landing. (I. U. Cat. No. 
12056.) 




Fig. 32. Outline of Pseudopimelodus villosus Eigenmann. Type. C. M. Cat. No. 1677. 

Cotype, one specimen, 38 mm. Kumaka, Demerara. (C. M. Cat. No. 1680.) 
Cotype, one specimen, 52 mm. Wismar. (C. M. Cat. No. 1679.) 
Head 3-3.2; depth 5-5.3; D. 1,6; A. 11; eye 3 in snout, 10 in head, 5 in 
distance between the eyes. 

Everywhere covered with fine hair-like filaments, these especially abundant 
above the pectoral. Width of head scarcely less than its length; depth of head a 
little more than half its length; head flat above; anterior nostrils with very short 
tubes; jaws equal; width of mouth equaling length of head without snout; depth 
of premaxillary bands of teeth 6 in their width; a sharp backward prolongation at 
the outer angle; maxillary barbel reaching middle of pectoral, outer mental barbel 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 153 

to the base of the last ray; inner mental barbels considerably in advance of the 
outer. 

Distance of dorsal spine from snout 2.4 in the length, the spine about half the 
length of the head, roughened with antrorse notches in front towards the tip, 
smooth behind; dorsal rays nearly all of the same height, equal to head less snout; 
caudal notched, the upper lobe longer, nearly equal to the length of the head; and 
rounded, reaching caudal; ventrals to anal; pectorals not to ventrals; pectoral 
spine strong, about equal to head without snout, with retrorse teeth along its 
entire posterior margin, its anterior margin with antrorse teeth which, in the adult, 
are nearly as long as the spine is wide. 

Marbled, dark and light brown, without distinct markings on the body, the 
area between the dorsals and below the posterior part of the adipose lighter in the 
younger specimens. Margin and a variable median band on the posterior rays 
of the dorsal light; caudal, anal, ventrals and pectorals profusely spotted, the 
margins hyaline. 

In the specimens mentioned by Miiller and Troschel and by Peters the premaxil- 
lary band of teeth have a backward projecting angle. Both are in such a bad state 
of preservation that I am not sure whether they are to be referred to this species 
or not. 

29. Pseudopimelodus albomarginatus sp. nov. (Plate XI, fig. 1.) 

Pseudopimelodus albomarginatus Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 384 (name only). 

Type, 98 mm. Tukeit. (Carnegie Museum Catalog of Fishes No. 1680.) 
Cotypes, twenty-one specimens, 33-108 mm. Tukeit. (C. M. Cat. No. 1681 
a-d; I. U. Cat. No. 12057.) 

Cotype, one specimen, 90 mm. Waratuk. (C. M. Cat. No. 1682.) 
Head 2.66-2.9; depth 4.66; D. 1,6; A. 10; eye 4 in snout; 12 in head, 5 in 
space between the eyes. 

Snout much depressed, head flat above; width of head but very little less 
than its length, its height equal to half its width; anterior nostrils with a tube 
projecting slightly beyond the upper lip; jaws equal, width of mouth equals length 
of head without the snout; width of premaxillary bands of teeth about 6 in their 
anterior margin, a long pointed backward projecting angle; maxillary barbel not 
quite reaching gill-opening; outer mental barbel scarcely shorter. 

Distance between snout and dorsal spine 2.25-2.3 in the length, the spine 
slightly rough on the upper half of its margins; dorsal rays of nearly equal height, 



154 MEMOIRS OF THE CARNEGIE MUSEUM 

2 in the head; caudal notched, the upper lobe much longer, nearly or quite equal 
to the length of the head; anal reaching lobe of caudal, ventrals to anal; pectorals 
not to ventrals; pectoral spine less than half the length of the head, its inner margin 
with strong recurved hooks, its outer margin with still larger teeth, antrorse near 
the tip, retrorse near the base. 

Black, with markings of brown, the lighter color forming a blotch on the 
sides, below the space between the dorsal and a few smaller irregular ones in front 
of it; adipose and upper surface of caudal peduncle and a spot on or near the lower 
surface of the peduncle also light brown. Dorsal black, its margin and a wedge 
entering the posterior rays hyaline; caudal with a median spotted area near its 
base, the margin white, the rest of the fin black; anal, ventrals and pectorals each 
with a light, clouded area at the base, and a broad black band and white margin, 
which is very narrow on the pectoral. 

30. Pseudopimelodus raninus (Cuvier and Valenciennes). 

Pirnelodus raninus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 157 

(Mana; Rio Janeiro).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 421 (Barra 

do Rio Negro; Guapore; Mattogrosso). 
Pseudopimelodus raninus Steindachner, " Flussfische Siidamerika's," iv, 1882, 

4 (Rio Huallaga). — Eigenmann and Eigenmann, Occasional Papers Cal. 

Acad. Sci., I, 1890, 111. 
Batrachoglanis raninus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 383 (name only). 

No specimens of this species were secured by me. The specimens mentioned 
by Giinther as from the Essequibo do not belong to this species. I examined the 
types. Three specimens, 91-110 mm. " De la Mana, Leschenault," in the Jardin 
des Plantes. 

Dorsal plate long, nearly touching the occipital process. Dorsal spine smooth; 
pectoral spine with strong teeth in front and behind, as wide as the spine. 
Maxillary barbel reaching a little bej^ond the tip of the humeral spine; a band be- 
tween the gill-openings, a submedian band on the last dorsal rays, tips of rays 
hyaline, anal similar, base and subterminal band of caudal dark. 

Two of the specimens are nearly uniform dark brown, one has a very distinct 
band between the gill-openings, and all have the entering wedge of light on the 
dorsal and anal and have the vertical fins margined with white. Villose as in 
villosus. 

All have backward projecting angles to the premaxillary bands of teeth. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 155 

Microglanis gen. nov. 11 

Type, Microglanis pcecilus sp. nov. 

Small Pimelodines, reaching a maximum length of 110 mm., with the head as 
wide as long, the skull covered by skin only; the occipital crest small; frontal 
fontanehnot extending much if any behind the eye, sometimes a minute occipital 
fontanel. Eye without a free orbital margin; dorsal and pectoral spines well- 
developed; premaxillary patches of teeth without backward projecting angles. 

The species of this genus parahybce and pulcher are variegated and marked 
with three more or less well-defined cross-bands, one over the nape, one behind the 
dorsal, and one across the caudal peduncle. 

31. Microglanis pcecilus sp. nov. 12 (Plate XII, fig. 2.) 

Eight specimens, 22-37 mm. Below Packeoo Falls. (C. M. Cat. No. 1676 
a and b; I. U. Cat. No. 12055.) 

The larger of the two specimens in the Carnegie Museum (a) may be considered 
the type. 

Head as wide as long, 3.4 in the length; depth 6; D. 1,6; A. 9; eye 2.5 in 
snout, 8 in head, 3.5 in distance between the eyes. 

Head depressed, snout rounded; barbels banded, the maxillary barbel reaching 
tip of humeral process, post-mental to base of last pectoral ray; mental barbel 
considerably in advance of the post-mentals; mouth wide, but its angle in front 
of the eye; lower jaw slightly projecting; anterior nares not tubular. 

Distance of dorsal from snout 2.4 in the length, the spine about twice as long 
as the eye; pectoral spine strong, with large teeth along the entire length of both 
margins, half of those of the outer margin retrorse, the other half antrorse; ventrals 
inserted behind the vertical from the last dorsal ray, just reaching the rounded 
anal; base of dorsal, adipose, and anal about equal in length; upper caudal lobe 
longer than head. 

A light, wavy band across the nape from the pectoral to pectoral; a light spot 
at base of dorsal spine; a light band downward and backward from behind the 
dorsal, joining another light band which extends upward but not to the dorsal spine; 
an oval light area in front of adipose; a light band across caudal peduncle; some 
light vermiculations about the snout; the light areas sometimes bordered by white, 
the extent of light and dark brown varying greatly, sometimes one and sometimes 
the other predominating. Pectoral light, with an oblique dark band; dorsal black, 

11 filxpos, small, 7Xai'is J cat-fish. 

12 The duplicates of this new species were distributed as Batrachoglanis raninus. 



156 MEMOIRS OF THE CARNEGIE MUSEUM 

its margin and a wedge near the middle of the posterior rays hyaline; caudal 
spotted, sometimes a narrow subterminal black band; anal and ventrals spotted; 
lower surface profusely but faintly spotted. 

Brachyglanis 13 gen. nov. 
Breviglanis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 384 

(name only). 

Type, Brachyglanis frenata sp. nov. 

Dorsal and pectoral spines well-developed, pungent; skull covered with a thick 
layer of muscle; ventrals under posterior half of dorsal; caudal forked, the lobes 
short and about equal; adipose fin not joined to the caudal; anal short; occipital 
process very short, the skull with a median ridge to near the eye, the fontanel 
short; eyes small, not strictly superior, without a free orbital notch; premaxillary 
patch of teeth without a backward projecting angle. 

Key to the Species of Brachyglanis. 

a. Maxillary barbel in the adult not reaching gill-openings when laid back, to the pectoral in the young; 

a dark streak from anterior nares through eyes to gill-openings; a light streak in front of dorsal. 

frenata. 
aa. Maxillary barbel extending to below the dorsal. 

b. Color uniform melas. 

bb. A broad quadrate light spot on the back in front of the dorsal phalacra. 

32. Brachyglanis frenata sp. nov. 

Breviglanis frenata Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
384 (name only). 

Type, 49 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1670.) 
Cotypes, two specimens, 41 and 68 mm. Amatuk. (I. U. Cat. No. 12052.) 
Head 3.5; depth about 5; D. 1,6; A. 7 or 8; eye 2 in the snout, 7.5 in the 
head, 1.5 in the distance between the ej-es. 

Tail compressed, depth nearly uniform from caudal peduncle to occiput; head 
tapering to the flat snout; head slightly rounded above, its width equal to its 
length exclusive of the part in front of the posterior nares, its depth equal to the 
postorbital part of the head; angle of mouth below front margin of eye; the tubular 
anterior nares projecting beyond the upper lip; maxillary barbel in the smallest 
extending to the pectoral spine, not to gill-opening in the largest; inner mental 
barbels but slightly in advance of the outer. 

Dorsal spine equal to snout and eye or a little less, the dorsal rays of nearly 

13 /Spax^s, short, y\dvis, cat-fish. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 157 

equal height, 2 in head; distance from snout to dorsal 2.7 in the length; adipose 
fin beginning at the tip of the dorsal, its margin rounded, free posteriorly; caudal 
short and very broad; anal short, rounded, its origin near the vertical from the 
middle of the adipose; pectoral fin reaching ventral, the spine short, pointed, with 
recurved hooks on both margins. 

Light brown, spotted and marbled with darker; a clavate light area in front 
of the dorsal; a dark streak from the anterior nares to the upper angle of the gill- 
opening; bases of dorsal and caudal opaque, then abruptly hyaline, the margin of 
the opaque area of the caudal blackish. 

33. Brachyglanis melas sp. nov. (Plate XI, fig. 2.) 

Breviglanis melas Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
384 (name only). 

Type, 60 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1672.) 
Cotypes, nine specimens, 36-53 mm. Crab Falls. (C. M. Cat. No. 1673a-6; 
I. U. Cat. No. 12053.) 

Cotype, one specimen, 44 mm. Georgetown market. (C. M. Cat. No. 1674a.) 
Cotypes, two specimens, 32-48 mm. Warraputa. (C. M. Cat. No. 1675a; 
I. U. Cat. No. 12054.) 

Head 3.8; depth 5.5-8; D. 1,6-9; A. 8, rarely 7. Maxillary barbel extending 
to below the dorsal; outer mental barbel to base of last pectoral ray or to gill- 
opening; origin of adipose fin some distance behind the tip of the dorsal, 5-5.5 in 
the length. Light brown to blue-black; no markings; fins as in frenat a. 

34. Brachyglanis phalacra sp. nov. (Plate XII, fig. 1, and Plate XIII, fig. 1.) 

Breviglanis phalacra Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

384 (name only). 

Type, 81 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1671.) 

Very similar to frenata. 

D. 1,8; eye 3 in snout, 11 in head, 2 in distance between the eyes; maxillary 
barbel reaching to below the middle of the dorsal, outer mental barbel to the gill- 
opening. 

Light brown, a dark margin to the opaque portion of the caudal; a large quad- 
rate yellow spot just behind the head, connected with a light bar extending down 
over the opercle. 

Otherwise as in frenata. 



158 MEMOIRS OF THE CARNEGIE MUSEUM 

Leptoglanis 14 gen. nov. 

Leptoglanis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 384 

(name only). 

Type, Leptoglanis essequibensis sp. nov. 

First dorsal ray soft or a minute spine; pectoral spine short but strong; origin 
of ventrals under posterior half of dorsal, far in advance of the middle; adipose 
fin long and low, continuous with caudal; caudal rounded; anal long; top of head 
covered with a thick layer of muscle ; an oval fontanel at the base of the occipital 
process; premaxillary patch of teeth subrhomboidal, with the outer posterior angle 
prolonged backward. 

35. Leptoglanis essequibensis sp. nov. (Plate XIII, fig. 2.) 

Leptoglanis essequibensis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 
III, 1910, 384 (name only). 

Type, 156 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1652.) 
Cotypes, four specimens, 90-170 mm. Crab Falls. (I. U. Cat. No. 12041.) 
Cotypes, five specimens, 50-170 mm. Warraputa. (C. M. Cat. No. 1653a; 
I. U. Cat. No. 12042.) 

Cotype, one specimen, 66 mm. Konawaruk. (C. M. Cat. No. 1654a.) 
Head 4-4.9; depth 9.5; D. 7 or 1,6; A. 15-17; eye 2.5-3 in snout, 8-11 in 
head. 

Elongate, depth of caudal peduncle equals depth at eyes; depth behind dorsal 
equals depth of head, which is equal to half its width; occipital crest very short, 
not nearly reaching dorsal; eye superior; anterior nostrils tubular, extending be- 
yond upper lip; posterior nostrils nearer the eyes than to the anterior; head, and 
especially the snout, depressed; mouth terminal, the lips thin, plicate; premaxillary 
patch of teeth subrhomboidal, the outer angle much prolonged, its depth at the 
middle about 1.5 in its outer edge; an oval fontanel at the base of the occipital 
process; no frontal fontanel. 

Angle of the mouth considerably in advance of the eye; maxillary barbel reach- 
ing to middle of dorsal in the adult, farther in the young; outer mental barbels on a 
line with the angles of the mouth, reaching the opercle; inner mental barbels con- 
siderably in advance of the outer, their distance from the edge of the lower lip 
equal to the distance between the outer barbels; four large pores on the lower lip. 
Pectoral spine strong, its length equal to half the length of the head, with 
teeth along the basal parts of both edges, much stronger in the young; pectorals 

14 XorrAs, slender, yXdvis, cat-fish. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 159 

not reaching ventrals; distance from snout to dorsal 3.3-3.4 in the length, the spine 
evident in the young, less than twice the length of the eye, becoming soft with age; 
adipose dorsal long and low, connected with a forward extension of the caudal, 
3.5 in the length; origin of ventrals near vertical from middle of dorsal or farther 
back. 

Ashy to steel-blue above; fins hyaline. 

Myoglanis 15 gen. nov. 
Myoglanis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 384. 

Type, Myoglanis potaroensis sp. nov. 

First ray of dorsal soft; pectoral spine very strong; skull entirely covered above 
by a thick layer of muscle; ventrals under posterior half of dorsal; caudal forked, 
the lower lobe longest ; adipose long and low, continued to the caudal, there being 
no caudal fulcra; a frontal fontanel, scarcely extending beyond the minute eyes; 
skull behind the fontanel narrow, with a median ridge; occipital crest narrow and 
short; eyes very smaU, directed slightly sidewise, mostly upward, no free orbital 
margin; the two premaxillary patches of teeth forming a crescent; anal long. 

It is probable that the Acentronichthys collettii of Steindachner belongs to this 
genus. 

36. Myoglanis potaroensis sp. nov. (Plate XIV, fig. 1.) 

Myoglanis potaroensis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 381 (name only). 

Type, about 58 mm. Creek at Tukeit. (Carnegie Museum Catalog of Fishes 
No. 1664.) 

Cotypes, sixteen specimens, the largest 60 mm. Tukeit. (C. M. Cat. No. 
1665a-d; I. U. Cat, No. 12048.) 

Cotypes, three specimens, 99-113 mm. Potaro Landing. (C. M. Cat. 
No. 1666a; I. U. Cat, No. 12049.) 

Cotypes, three specimens, 35-40 mm. Waratuk. (C. M. Cat, No. 1667a; 
I. U. Cat. No. 12050.) 

Cotype, one specimen, 33 mm. Erukin. (C. M. Cat. No. 1668a.) 

Cotypes, eight specimens, 32-80 mm. Amatuk. (C. M. Cat. No. 1669a-6; 
I. U. Cat. No. 12051.) 

Head 4-4.3; depth 5.3-8; D. 6 to 8; A. 16-21; width of head equals its length 
without snout; depth of head 2 in its length; eye 14 in head, 3.5 in snout, 5 in space 
between the eyes. 

i6 m5s, muscle, TXdm, cat-fish. 



160 MEMOIRS OF THE CARNEGIE MUSEUM 

Compressed behind, depth from occiput to middle of anal nearly equal; head 
not greatly depressed, rounded above; occipital process short, its tip a little nearer 
to the dorsal than to the line between the posterior margins of the eye: anterior 
nostril very close to the lip; lips very thin, smooth; angle of snout below the eye; 
maxillary barbel reaching tip of pectoral in the adult, somewhat farther in the 
young; inner mental barbel in advance of the line joining the outer. 

Distance from dorsal to snout 2.6 in the length; tip of dorsal about reaching 
adipose, which is about 3 in the length; caudal frequently divided to the base, 
the lower lobe the longer; pectoral spine strong, not quite half the length of the 
head, with recurved spines on both margins; anal long, the tips of some of the 
rays reaching caudal, its base 3.5-4 in the length. 

Purplish brown, lighter below, the rayed fins lighter. No distinct markings. 

Chasmocranus 16 gen. nov. 
Chasmocephalus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

384 (name only, preoccupied). 

Type, Chasmocranus longior sp. nov. 

First rays of pectoral and dorsal soft ; origin of ventrals under origin of dorsal 
or but slightly behind it, far in advance of the middle; caudal forked; top of skull 
covered with skin only; fontanel narrow, extending to the base of the occipital 
interrupted over the eyes and again some distance behind the eyes; occipital crest 
short and narrow; eyes superior, without a free orbital margin; adipose fin low, 
not connected with the caudal; premaxillary patch of teeth subrhomboidal, its 
outer posterior angle extended backward; anal short. 

Closely allied to Heptapterus and Acentronichihys. 

Key to the Species op Chasmocranus. 

a. Adipose fin 3.5-4.5 in the length longior. 

aa. Adipose fin about 6 in the length brevior. 

37. Chasmocranus longior sp. nov. (Plate XIV, fig. 2.) 

Chasmocephalus longior Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 384 (name only). 

Type, 110 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1655.) 

Cotypes, twelve specimens, 40-93 mm. Amatuk. (C. M. Cat. No. 1656a-c; 
I. U. Cat. No. 12043.) 

Cotypes, three specimens, 95-129 mm. Maripicru ? (C. M. Cat. No. 1657a; 
I. U. Cat. No. 12044.) 

16 x«m«, a gaping, xpimr, head. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 161 

Cotype, one specimen, 89 mm. Waratuk. (C. M. Cat. No. 1658a.) 

Cotypes, two specimens, 67 and 68 mm. Konawaruk. (C. M. Cat. No. 
1659a; I. U. Cat. No. 12046.) 

Cotypes, twelve specimens, 38-83 mm. Warraputa. (C. M. Cat. No. 1660 
a-c; I. U. Cat. No. 12046.) 

One specimen, 60 mm. Warraputa. (C. M. Cat. No. 1661a.) This may 
prove to be distinct. 

Very similar to Leptoglanis. 




Fig. 33. Chasmocranus longior Eigenmann. Type. C. M. Cat. No. 1655. 

Head 4.5-5; depth 9-10; D. 7; A. usually 11 or 12, rarely 10; width of head 
less than its length, its depth 2 or 3 in its length; eye 6-7 in head. 2-2.66 in snout, 
1-1.33 in distance between the eyes. 

Head depressed, tail compressed ; tip of occipital crest about equidistant from 
snout and dorsal; anterior nostril nearer the snout than to posterior nostril; lips 
thin, plicate; mouth terminal, its angle about midway between anterior and pos- 
terior nostrils; depth of premaxillary patch of teeth about 1.5 in the length of its 
outer margin; maxillary barbel extending to or a little beyond origin of pectoral; 
outer and inner mental barbels in a straight line, their distance from the edge of 
the lower lip equal to the distance between the inner barbels. 

Distance of dorsal from tip of snout 2.5-2.66 in the length, the rays from the 
second to the sixth of about equal height; ventrals and dorsal equidistant from 
tip of snout; pectorals rounded, equal to head less snout in length; origin of anal 
under origin of adipose, its base long, last but fourth ray highest or of equal height 
with those immediately in front of it; caudal slightly forked, the lobes rounded, of 
nearly equal length, considerably less than length of head. 

Dark brown to black; sometimes a light streak across back from gill-opening 
to gill-opening; a light spot at base of first dorsal ray; fins light brown or blackish 
with white margins. 



162 MEMOIRS OF THE CARNEGIE MUSEUM 

38. Chasmocranus brevior sp. nov. (Plate XV, fig. 1.) 

Chasmocephalus brevior Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 384 (name only). 

Type, 56 mm. Waratuk. (Carnegie Museum Catalog of Fishes No. 1662a.) 
Cotypes, two specimens, 69 mm. Waratuk. (I. U. Cat. No. 12047.) 
? One specimen, 23 mm. Amatuk. (C. M. Cat. No. 1663a.) 
This species differs from longior in having more pointed caudal lobes, and 

especially in the length of the adipose fin, which is contained six times in the length. 

Rhamdia Bleeker. 

Pimelodus Lacepede, Hist. Nat. Poiss., V, 1803, — (sp.). — Cuvier, Regne Animal, 

II, 1817, 203 (sp.).— Gunther, Catalogue, V, 1864, 114 (sp.). 
Pteronotus Swainson, Class. Fishes, Amph., and Rept., II, 1839, 309 (5-tentaculatus) , 

preoccupied in mollusks. 
Rhamdia Bleeker, Icth. Arch. Ind. Prodr., I, 1858, 197, 207 (sp.); Nederl. 

Tijdschr. Dierk., I, 1863, 101 (queleni). 
Pimelonotus Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 391 (yilsoni). 
Notoglanis Gunther, Catalogue, V, 1864, 136 {multiradiatus) . 

Type, Pimelodus quelen Quoy and Gaimard. 

Eye with a free orbital margin. Teeth on vomer none or minute; occipital 
process short, not reaching the dorsal plate; no parietal fontanel; head covered 
with skin, not granular; caudal forked; barbels terete. 



Key to the Guiana Species of Rhamdia. 
a. D. 1,6 or 7. 

b. Premaxillary band of teeth rounded laterally. 

c. Maxillary barbel not or very rarely extending to middle of adipose. Space between the eyes 

2.2-2.6 in the head, both caudal lobes rounded, not quite as long as head, the sixth ray 

of the upper lobe from the median cleft longest; eye 3 in the snout, 6.5-7 in the head, 

3 in the space between the eyes; adipose dorsal 2.5 in the length quelen. 

cc. Maxillary barbel extending past middle of adipose; upper caudal lobe pointed; the fifth ray 

of the upper lobe from the median cleft longest: space between the eyes about 2.33 in 

the head sebae. 

bb. Premaxillary band of teeth with a backward projecting angle laterally. Maxillary barbel not 

extending to middle of adipose; space between the eyes 3 in the head; caudal cleft, both 

lobes rounded, the third or fourth ray from the cleft in the upper lobe longest; adipose dorsal 

2-2.4 in the length holomelas. 

aa. D. 1,10; A. 6; maxillary barbel to tip of ventrals arekaima. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 163 

39. Rhamdia quelen (Quoy and Gaimard). 

Pimelodus quelen Quoy and Gaimard, Voy. Uranie, Zool., 1824, pi. 49, figs. 3-4. 

Rhamdia quelen Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 
126 (Santa Clara; Rio Mucuri; Juiz de Fora; Campos; Rio Jequitinhonha; 
Mendez; Rio de Janeiro; Macacos; Sao Matheos; Rio Parahyba; Canna- 
vierias; Rio Grande do Sul); Occasional Papers Cal. Acad. Sci., I, 1890, 127; 
Proc. U. S. Nat. Mus., XIV, 1891, 28.— Berg, An. Mus. Nac. Buenos Aires, 
IV, 1895, 133.— Eigenmann and Norris, Rev. Mus. Paulista, IV, 1900, 350 
(Taubate). — Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 
499 (Estancia la Armonia; Asuncion; Campo Grande). — Eigenmann and Bean, 
Proc. U. S. Nat. Mus., XXXI, 1907, 660 (Amazon).— Eigenmann, Ann. Car- 
negie Mus., IV, 1907, 113 (Corumba); Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 386. 

Rhamdia queleni Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 101 (name only). 

Pimelodus queleni Gunther, Catalogue, V, 1864, 123 (Brazil). — Boulenger, 
Boll. Mus. Zool. Anat. Comp. Torino, XV, 1900, — (Carandasinho). 

Pimelodus {Rhamdia) queleni Steindachner, " Siisswasserfische Siidostlichen 
Brasilien," iii, 1876, 64 (Rio Parahyba, near Juiz de Fora; Campos; Rio 
Doce; Porto Alegre; Cannavierias; Amazon, near Para; Bahia). 

Heterobranchus sextentaculatus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 28, 
pi. 11 (12 in. long; locality?). 

Pimelodus sellonis Muller and Troschel, Horse Ichth., Ill, 1849, 2 (Brazil). 

? Pimelodus bahianus Castelnau, Anim. Am. Sud, Poiss., 1855, 35, pi. 16, fig. 2 
(Bahia). 

Pimelodus sebce Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 417, fig. 19 (Maar- 
bitanos) . 

Silurus sapipoca (ex Natterer, MS.) Kner, SB. Akad. Wiss. Wien., XXVI, 1857, 418. 

Pimelodus wuchereri Gunther, Catalogue, V, 1864, 123 (Bahia). 

Pimelodus (Rhamdia) queleni cuprea Steindachner, "Siisswasserfische Siidostlichen 
Brasilien," iii, 1876, 65 (Juiz de Fora). 

Pimelodus (Rhamdia) cuyabce Steindachner, " Siisswasserfische Siidostlichen 
Brasilien," iii, 1876, 75, footnote (Cuyaba). 
Six specimens, 112-169 mm. Gatuck Creek, Potaro Highlands. (C. M. Cat. 

No. 1594a-b; I. U. Cat. No. 11999.) 

Forty-one specimens, 71-230 mm. Aruataima. (C. M. Cat. No. 1595a-i; 

I. U. Cat. No. 12000.) 



164 MEMOIRS OF THE CARNEGIE MUSEUM 

Six specimens, 107-184 mm. Yackeatonuk Fall, Potaro River. (C. M. Cat. 
No. 1596a-&; I. U. Cat. No. 12001.) 

Eight specimens, 86-168 mm. Nickaparu Creek. (C. M. Cat. No. 1604a-c; 
I. U. Cat, No. 12002.) 

Fifteen specimens, 80-219 mm. Guiana, label not legible, collected by Indians 
in the upper Potaro or upper Rupununi. (C. M. Cat. No. 1605a-e; I. U. Cat. 
No. 12005.) 

One specimen, 215 mm. Potaro Landing. (C. M. Cat, No. 1597a.) 

Thirteen specimens, 78-164 mm. Holmia, creeks. (C. M. Cat. No. 1598a-e; 
I. U. Cat, No. 12003.) 

Three specimens, 205-242 mm. Chipoo Creek, branch of the Ireng. (C. M. 
Cat, No. 1599a; I. U. Cat, No. 12004.) 

This species inhabits the plateaus of Guiana. It has not been recorded from 
Guiana before. It is very closely allied to sebce, from which it differs principally 
in its longer maxillary barbel. 

Head 4.16-4.5; depth 5-4.3; D. 1,6; A. 11. 

Head about an orbital diameter longer than broad; eye in middle of head, 6.5 
in head in adult, 2.5 in interorbital ; maxillary barbel reaching middle of adipose 
in the young, not to middle in the old; outer or post-mental barbel not reaching 
beyond pectoral; dorsal spine equaling snout in adult; pectoral spine a little 
longer; spines shorter in the young; adipose fin half of the length without the head; 
caudal cleft to its base, the upper lobe narrower, both lobes rounded, equal to the 
head. Ashy above, blotched with darker; base of dorsal opaque at base, then 
hyaline, darker above; other fins uniform. 

40. Rhamdia sebae (Cuvier and Valenciennes). 

" Rhamdia ou bagre de rio " Marcgrave, Hist, Rer. Nat. Bras., IV, 1648, 149. 
- Seba, Locupl. Rer. Nat, Thes. Ace. Descr., Ill, 1748, pi. 29, fig. 5. 



" Mystus " No. 83, Gronow, Mus. Ichth., 1, 1754, 34; No. 384, Zoophyl., 1763, 125. 

Pimelodus sebce Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 169 
(Surinam; Cayenne; Rio Janeiro; Buenos Aires). — Muller and Troschel, 
in Schomburgk, Reisen, III, 1848, 628 (all Guiana rivers). — Hyrtl, Denkschr. 
Akad. Wiss. Wien, XVI, 1859, 16 (vertebrae 11 + 2 + 26).— Quoy and 
Gaimard, Voy. Uranie et Physicienne, Zool., 1824, 228, pi. 49, figs. 3 and 4.— 
Gunther, Catalogue, V, 1864, 119 (Demerara; British Guiana; Brazil). 

Pimelodus [Rhamdia) sebm Steindachner, " Siisswasserfische Siidostlichen 
Brasilien," iii, 1876, 68 (Demerara; Essequibo; St. Martha, mouth of 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 165 

Magdalena) ; " Fisch-Fauna Magdalenen-Stromes," 1878, 17 (Magdalena) ; 

" Fisch-Fauna des Cauca," etc., 1880, 7 (Cauca). 
Rhamdia sebce Eigenmann and Eigenmann, Proc. Cal. Acad. Sci. (2), I, 1888, 126 

(Tonantins; Gurupa; Rio Janeiro; Bahia; Xingu; Santa Cruz; Cudajas; Sao 

Matheos; Rio Doce; Serpa; Tabatinga; Goyaz; Para; Teffe; Surinam; 

Villa Bella); Occasional Papers Cal. Acad. Sci., I, 1890, 123; Proc. U. S. 

Nat. Mus., XIV, 1891, 28.— Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 385. 
Pimelodus stegelichii Mulle and Troschel, in Schomburgk, Reisen, III, 1848, 628 

(forest brooks); Horae Ichth., Ill, 1849, 3 (Surinam). — Gunther, Catalogue, 

V, 1864, 121 (Demerara; Surinam). 
Pimelodus musculus Muller and Troschel, Horse Ichth., Ill, 1849, 4 (America). 
Pimelodus mulleri Gunther, Catalogue, V, 1864, 119 (River Capin; Para; Surinam). 
Rhamdia queleni Bleeker (not of Quoy and Gaimard), " Silures de Suriname," 

1864, 75 (Surinam). 

Twenty-nine specimens, 96-246 mm. Mud creek in Aruka River. (C. M. 
Cat. No. 1588a-e; I. U. Cat. No. 11194.) 

One specimen, 119 mm. Below Packeoo Falls, Essequibo. (C. M. Cat. No. 
1589a.) 

Seven specimens, 118-226 mm. Creek in Barima River. (C. M. Cat. No. 
1590a-6; I. U. Cat. No. 11995.) 

Five specimens, 150-280 mm. Creek in Mora Passage. (C. M. Cat. No. 
1591o-6; I. U. Cat. No. 11996.) 

Fourteen specimens, 129-228 mm. Gluck Island, Rockstone. (C. M. Cat. 
No. 1592a-e; I. U. Cat. No. 11997.) 

One specimen, 153 mm. Kumaka. (C. M. Cat. No. 1593.) 

One specimen, 294 mm. Lama Stop-Off . (I. U. Cat, No. 11998.) 

One specimen, 200 mm. Georgetown, mud-flats. (C. M. Cat. No. 1601.) 

One specimen, 220 mm. Botanic Gardens. (C. M. Cat. No. 1602.) 

One specimen, 244 mm. Wismar. (C. M. Cat. No. 1603.) 

I have also examined the types of stegelichii in Berlin. 

Head 4-4.25; depth 3.3-5.16; D. 1,6; A. 10-12; eye in the middle or slightly 
in advance of the middle of the head, 6-6.5 in the head in the adult, 2-2.5 in the 
interorbital; maxillary barbel reaching beyond middle of adipose, to tip of caudal 
in some young; post-mental barbels to tip of pectoral or beyond origin of ventral. 
Dorsal spine somewhat longer than snout in adult (shorter in young) ; pectoral 
spine somewhat longer than snout and eye in the adult; adipose fin nearly half the 



166 MEMOIRS OF THE CARNEGIE MUSEUM 

length from eye to caudal. Upper caudal lobe more pointed than in quelen, equal 
to the length of the head. Ashy to black, with darker mottlings, or plain, other- 
wise as in quelen. 

One of the types, 262 mm. long, in the Jardin des Plantes has the maxillary 
barbel extending to the second third of the adipose only (the specimen mentioned 
by Cuvier and Valenciennes from Guayaquil is another species), upper caudal 
lobes rounded, the fourth ray longest. 

41. Rhamdia holomelas (Gunther). 
Pimelodus holomelas Gunther, Ann. and Mag. Nat. Hist., (3), XXII, 1863, 442 

(Essequibo); Catalogue, V, 1864, 120 (Essequibo). 

I have examined the types in the British Museum and seven specimens, 275- 
345 mm. Lama Stop-Off . (C. M. Cat. No. 1600« and 2227a-c; I. U. Cat. No. 12413.) 

Head 4-4.2; depth 5.5-5.66; D. 6; A. 11-13; adipose dorsal 2-2.4 in the length. 

Head about an orbital diameter longer than broad, its depth half of its length; 
interorbital flat, the snout distinctly depressed, the upper jaw longer; premax- 
illary band of teeth five and a half times as long as deep, a distinct backward pro- 
jecting angle laterally; maxillary barbel extending beyond the base of the pectoral 
but not to its tip, post-mental a little beyond the base of the pectoral. Caudal cleft 
to the base, one short ray on either side of the cleft; the second ray of the upper lobe 
nearly as long as the third and fourth ; both lobes rounded ; pectoral spine equal to 
the postorbital portion of the head or a little longer, with retrorse hooks in front, 
slightly rough near the middle behind. Black, with obscure marblings. 

42. Rhamdia arekaima (Schomburgk) . 
Pimelodus arekaima Schomburgk, Fishes Brit. Guiana, I, 1841, 178 (not pi. 5), 

(Upper Essequibo). — Muller and Troschel, in Schomburgk, Reisen, III, 

1848, 643 (all rivers of the savannah). 
Pimelodus multiradiatus Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 414 (Borba 

on the Rio Madeira; Forte do Rio Branco on the Rio Takutu). 
Notoglanis multiradiatus Gunther, Catalogue, V, 1864, 136 (copied). 
Rhamdia multiradiatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 126 (name) ; Occasional Papers Cal. Acad. Sci., 1, 1890, 130. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 386, part. 

Habitat, Amazon and its tributaries, and northward. 

This species is placed here on the authority of Schomburgk. The plate of 
Schomburgk 's arekaima is apparently Pimelodus clarias and the description does 
not fit it. The specimen from which the drawing was made was said to be two feet 
three inches long, of fine flavor, and called "Tiger fish." 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 167 

Rhamdella Eigenmann and Eigenmann. 

Rhamdella Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 129 

{eriarcha) . 

Type, Rhamdella eriarcha Eigenmann and Eigenmann. 

This genus differs from Rhamdia in the presence of a long slit-like parietal 
fontanel. Most of the species are found in southeastern Brazil. 

43. Rhamdella foina (Midler and Troschel). 
Pimelodus foina Muller and Troschel, in Schomburgk, Reisen, III, 1848, 628 

(Takutu); Horse Ichth., Ill, 1849, 5 (Guiana). — Gunther, Catalogue, V, 

1864, 130 (copied). 
Rhamdia foina Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 126 

(name); Occasional Papers Cal. Acad. Sci., I, 1890, 126; Proc. U. S. Nat. Mus., 

XIV, 1891, 28. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 386. 

This species has been taken but once before; I have examined the type in 
Berlin and five specimens, 141-201 mm. Warraputa Cataract. (C. M. Cat. No. 
1587a-b; I. U. Cat. No. 12007.) 

Head 4; depth 5-6.5; D. I, 6; A. 10. 

Head much depressed, its depth equal to eye and postorbital part of head, its 
width equal to the length behind the maxillary barbel; head evenly arched from 
its lower margin to its lower margin, the eyes directed upward and outward, 4 in 
the head, two-thirds of the interorbital; occipital fontanel long and narrow ; occip- 
ital process very short, extending about one-fourth of the distance to the dorsal 
spine. Premaxillary teeth fine, in a band of about equal width throughout. 
Maxillary barbel extending slightly beyond tip of pectoral; post-mental a little 
beyond their base. 

Dorsal spine two-fifths the length of the head; base of dorsal a little less than 
its distance from the adipose, which is 3.5 in the length. Caudal forked, not cleft 
to its base, the lower lobe rounded, the upper lobe pointed, .4 longer than the 
lower, 3.5 in the length; depth of caudal peduncle about half its length. 

Uniform blue-black to mottled ashy; dorsal uniform or its base darker. 

Pimelodella Eigenmann and Eigenmann. 
Pseudorhamdia Steindachner, " Siisswasserfische SiidostlichenBrasilien," iii, 1876, 

46 (lateristriga) , not Pseudorhamdia Bleeker. 
Pimelodella Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 131 

(cristatus) . 



168 MEMOIRS OF THE CARNEGIE MUSEUM 

Type, Pimelodus cristatus Miiller and Troschel. 

Similar to Pimelodus, but with a parietal fontanel persistent throughout life; 
the occipital process not tapering, but of nearly uniform width, in contact with 
the dorsal plate behind; no vomerine teeth. 

Species usually slender and of small size. 

Key to the Guiana Species of Pimelodella. 
a. Adipose fin 2.33-2.5 in the length. A narrow lateral band, conspicuous in young, becoming obscure 

with age. Maxillary barbels to below middle of adipose or beyond tip of caudal cristata. 

aa. Adipose fin 3 or more in the length. 

6. Eye 2.5 in the head, longer than snout; interorbital 2 in the eye; maxillary barbel reaching end of 
adipose or caudal; caudal lobes long, slender, the lower 3 in the length; pectoral spine little 

shorter than head megalops. 

66. Eye 3.5 in head, shorter than snout; tip of dorsal dusky; maxillary barbel reaching middle of 
adipose; pectoral spine about equal to snout and eye macturki. 

44. Pimelodella cristata (Miiller and Troschel). 

? Pimelodus insignis Schomburgk, Fishes Brit. Guiana, 1, 1841, 180 (not plate). — 
Muller and Troschel, in Schomburgk, Reisen, III, 1848, 643 (Takutu and 
Rio Branco). 

Pimelodus cristatus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 628 
(Takutu and Mahu Rivers); Horae Ichth., Ill, 1849, 4 (Guiana, in Esse- 
quibo). — Gunther, Catalogue, V, 1864, 117 (Guiana; Essequibo; River Capin, 
Para).— Vaillant, Bull. Soc. Philom., (7), IV, 1880, 152 (Calderon) .— Stein- 
dachner, " Flussfische Siidamerika's," iv, 1882, 4 (Rio Huallaga). — ? Perugia, 
Ann. Mus. Genova, (2), X, 1891, 631 (Tucuman). 

Pimelodella cristata Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 
132 (San Goncallo; Avary; Villa Bella; Jutahy; Tapajos; Rio Mucuri; 
Tabatinga; Hyavary; Coary); Occasional Papers Cal. Acad. Sci., I, 1890, 150.— 
Eigenmann and Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 660 (Amazon).— 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 388. 

Pimelodus agassizii Steindachner, " Icthyologische Beitrage," v, 1876, 99 
(Peruvian Amazon; Hyavary). 

Pimelodus (Pseudorhamdia) wesselii Steindachner, " Stisswasserfische Siidostlichen 
Brasilien," iii, 1876, 56, footnote (Essequibo). 

? Pimelodella wesselii Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 
1888, 132 (Cudajas; Para; Marajo; Rio Madeira; Rio Puty; Santarem); 
Occasional Papers Cal. Acad. Sci., I, 1890, 152. 

Pimelodus ophthalmicus Cope, Proc. Am. Philos. Soc, XVII, 1878, 675 (Upper Ama- 
zon). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 169 

Without opening the question whether the specimens recorded by Eigenmann 
and Eigenmann as cristatus and wesselii belong to distinct species, I am inclined 
to consider the wesselii of Steindachner as a synonym of the cristatus of Miiller 
and Troschel. I have examined the type of cristatus and: 

Twelve specimens, 81-137 mm. Tumatumari. (C. M. Cat. No. 1686a-d; 
I. U. Cat, No. 12062.) 

One specimen, 145 mm. Below Packeoo Falls. (C. M. Cat, No. 1687.) 

One specimen, 105 mm. Rockstone. (C. M. Cat. No. 1688.) 

Two specimens, 115-150 mm. Konawaruk. (C. M. Cat. No. 1689; I. U. 
Cat, No. 12063.) 

Twelve specimens, 160-205 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1690a- f /; I. U. Cat. No. 12064.) 

Two specimens, 133-158 mm. Twoca Pan. (C. M. Cat, No. 1691a; I. U. 
Cat. No. 12065.) 

Essequibo and creeks of the interior, most abundant in the lower Potaro River. 

Head 4.5; depth 4.5-5.75; D. 1,6; A. 13-15; adipose fin 2.25-2.4; eye 3.5-4 
in the head, interorbital 4.25-5; half the eye or all of it in the posterior half of 
the head. 

Occipital crest more than three times as long as wide, reaching the dorsal 
plate; fontanels of about equal width, the posterior becoming very narrow behind; 
maxillary barbels extending to the base of the caudal or slightly beyond its tip; 
outer mental barbels reaching ventrals or in the largest specimens a little shorter. 

Dorsal rounded, the spine slender, about equal to the fourth ray in height; 
anterior margin of the dorsal spine with recurved notches on its distal half or less, 
posterior margin with small recurved hooks; interspace between the dorsals about 
equal to the eye; caudal deeply forked, frequently split to the base, the lower lobe 
much the broader; ventrals not reaching anal; pectoral not to ventral; pectoral 
spine with small hooks along the posterior margin, its anterior margin rough, with 
recurved notches on distal half. A narrow blue-black stripe from below origin 
of dorsal, disappearing near caudal, and becoming obscure with age; dorsal 
with the usual hyaline band. 

45. Pimelodella megalops sp. nov. (Plate XV, fig. 2.) 

Pimelodella megalops Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 389. 

Type, 100 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 1692.) 
Cotypes, fifty-six specimens, 67-96 mm. Tumatumari. (C. M. Cat. No. 

1693a-e; I. U. Cat. No. 12066.) 



170 MEMOIRS OF THE CARNEGIE MUSEUM 

Three specimens, 56-90 mm. Crab Falls. (C. M. Cat. No. 1694; I. U. Cat. 
No. 12067.) 

Allied to macturki, but with a distinctly larger eye and a longer and more slender 
lower caudal lobe. 

Head 4.75-5; depth 6.5-7; D. 1,6; A. 11 to 13; adipose fin 3.33 in the length; 
eye 2.5 in the head, its center a little behind the middle of the head; interorbital 
5.5 in the head. 

Width of occipital crest 2.5-3 in its length, reaching dorsal plate; posterior 
fontanel considerably wider than the anterior for a short distance, narrowed back- 
ward; maxillary barbel reaching to near end of adipose or base of caudal; outer 
mental barbels reaching the ventrals. 

Dorsal spine slender, equal to the third or fourth ray in height ; a few scarcely 
evident recurved notches near the tip in front, and fine recurved teeth for nearly its 
entire length behind; space between the dorsals considerably greater than the 
large eye; caudal very widely forked and sometimes split to the base, the lower 
lobe longer than the upper by nearly the length of the eye, 2.75-3 in the length; 
pectoral spine but little shorter than head, with minute straight teeth along its 
anterior margin to the tip, where they are replaced by recurved hooks, posterior 
margin with about eighteen recurved spines near the tip, the spines largest near 
the middle. 

A dark median band; dorsal hyaline, a narrow streak of chromatophores along 
the front of each ray. 

46. Pimelodella macturki sp. nov. (Plate XVI, fig. 1.) 

Pimelodella macturkii Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 389. 

Type, 69 mm. Creek in Mora Passage. (Carnegie Museum Catalog of Fishes 
No. 1695.) 

Cotypes, fourteen specimens, 46-76 mm. Creek in Mora Passage. (C. M. 
Cat. No. 1696a-e; I. U. Cat, No. 12068.) 

Cotypes, two specimens, 66 and 65 mm. Georgetown trenches. (C. M. Cat. 
No. 1697; I. U. Cat, No. 12069.) 

Cotypes, fifteen specimens, 49-71 mm. Choca trenches at Morowhanna. (C. 
M. Cat. No. 1698a-rf; I. U. Cat. No. 12070.) 

This species takes the place of cristata along the coast from Georgetown to 
Morowhanna. It differs notably in the length of the adipose and barbels, the color 
of the dorsal, and the serration on the pectoral spine/ 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 171 

Head 4-4.5; depth 5.25; dorsal 1,6; A. 10-13; adipose fin 3.5-4 in the length; 
eye 3.33-4; interorbital 4.5; eye about in middle of the head. 

Occipital crest more than three times as long as wide, reaching the dorsal 
plate; fontanels of about equal width, the posterior becoming narrower backward; 
maxillary barbel reaching origin or end of base of anal; outer mental barbel to 
near tip of pectoral or a little shorter. 

Dorsal low, rounded, the spine equal to the third or fourth ray, rough near 
the tip in front and on the distal half of the posterior margin; space between the 
dorsals much greater than the eye; caudal deeply forked, the lower lobe broader, 
a little longer than the head, 3.5 in the length; ventrals not reaching anal ; pectorals 
not to ventrals; pectoral spine equal to snout and eye in length or a little longer, 
with minute teeth along its anterior margin to near the tip, with twelve long re- 
curved spines along the middle of its posterior margin, the larger nearest the tip. 

An obscure lateral stripe; tip of caudal dusky. 

Pimelodus Lacepede. 
Pimelodus Lacepede, Hist. Nat. Poiss., V, 1803, — (species of several genera). — ■ 

Cuvier, Regne Animal, II, 1817, 203 (species having a single band of teeth in the 

upper jaw). — Swainson, Class. Fishes, Amph., and Rept., II, 1839, 305 

(quadrimaculatus) . — Lutken, Dan. Vidensk.-Selsk., Skr., (5), XII, 1875, 163 

(macidatus = clarias). 
Pseudariodes Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 99 (clarias). 
Pseudorhamdia Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 101 (macidatus = 

clarias) . 
Pseudorhamdia Lutken, Dan. Vidensk.-Selsk. Skr., (5), XII, 1875, 49, 169 (fur). 

Type, Pimelodus macidatus Lacepede. 

Eye with a free orbital margin; teeth on vomer none or minute; occipital 
process reaching the dorsal plate; no parietal fontanel; head covered with thin skin, 
granular; caudal forked; humeral process broad; barbels terete. 

Key to the Guiana Species of Pimelodus. 
a. Adipose dorsal about 4 or more than 4 in the length. 

b. Occipital process broad at base, tapering to the dorsal plate. 

c. Pectoral spine smooth or nearly smooth in front. Dorsal without a conspicuous spot; sides 
spotted, striped or plain; snout narrowed, its width less than half the length of the 
head; posterior nares large; upper jaw but little projecting; dorsal spine reaching 

considerably beyond tip of last ray clarias. 

cc. Pectoral spine with antrorse teeth in front and retrorse teeth behind. Dorsal with a con- 
spicuous black blotch near the middle of the front half of the fin; a light streak from 



172 MEMOIRS OF THE CARNEGIE MUSEUM 

dorsal spine to above ventral and then back to the middle caudal rays, another light 
streak above it; snout broad, depressed, the width of the mouth about half the length 
of the head; posterior nares small; upper jaw considerably projecting; dorsal spine not 

nearly reaching tip of last ray ornatus. 

bb. Occipital process narrow at the base, scarcely tapering to the tip; pectoral spine with retrorse 

teeth on the basal half of the posterior margin; without conspicuous markings, the chroma- 

tophores in an area between the anal and dorsal aggregated along the septa. .heteropleurus. 

aa. Adipose dorsal very long, 2.4-2.6 in the length; caudal lobes produced, twice as long as the head, 

maxillary barbels extending much beyond the tips of the caudal altipinnis. 

47. Pimelodus clarias (Bloch). 

Silurus clarias Bloch, Ausl. Fische, 1795, pi. 35, figs. 1-2 = Silurus clarias Linnaeus 
in part; not Silurus clarias Hasselquist, which is Synodontis clarias from the Nile. 

Pimelodus clarias Lacepede, Hist. Nat. Poiss., V, 1803, 93 (? 8 dorsal rays); Cas- 
telnau, Anim. Am. Sud, Poiss., 1855, 34 (Crixas; Araguay; Ucayale; Ama- 
zon). — Steindachner, "Fisch-Fauna Magdalenen-Stromes," 1878, 15 (Mag- 
dalena River); "Flussfische Siidamerika's," xiv, 1882, 4 (Rio Huallaga).— 
Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 134.— 
Eigenmann, Ann. N. Y. Acad. Sci., VII, 1894, 633 (Rio Grande do Sul) .- 
Eigenmann and Norris, Rev. Mus. Paulista, IV, 1900, 353 (Iguape). — Eigen- 
mann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 499 (Asuncion; Arroyo 
Trementina). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 388. 

Bagrus (Ariodes) clarias Muller and Troschel, in Schomburgk, Reisen, III, 1848, 
627 (Waini and Barima). 

Ariodes clarias Muller and Troschel, Horse Ichth., Ill, 1849, 10 (British 
Guiana).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 413. 

Pseudariodes clarias Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 99 (name only). — ■ 
Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 194, 199 (Guiana). 

Silurus callarias Bloch and Schneider, Syst. Ichth., 1801, 379, part. 

Pimelodus maculatus Lacepede, Hist. Nat. Poiss., V, 1801, 94, 107 (Rio Plata). — 
Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, pi. 1, figs. 1-3 (La 
Plata to Mexico, Lake Maracaibo). — Cuvier and Valenciennes, Hist. Nat. 
Poiss., XV, 1840, 192 (Cayenne; Maracaibo). — Schomburgk, Fishes Brit. 
Guiana, 1, 1841, 175 (Rivers of Guiana generally; Rio Negro; Amazon). — Stein- 
dachner, " Icthyologische Notizen," vi, 1867, 32 (La Plata) ; ix, 1869, 6 (Monte- 
video). — Hensel, Archiv fur Naturg., I, 1870, 69 (Jacuhy). — Lutken, Dan. 
Vidensk.-Selsk. Skr., (5), XII, 1875, 163, fig. (Rio das Velhas). — Steindachner, 
"Siisswasserfische Siidostlichen Brasilien," iii, 1876, 40 (La Plata ; Rio San Fran- 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 173 

cisco; Rio das Velhas; Amazon between Para and Santarem; Rio Grande do Sul; 
Porto Alegre).— Peters, MB. Akad. Wiss. Berlin, 1877, 470 (Calabozo) — 
Boulenger, Proc. Zool. Soc. London, 1891, 233 (Rio Grande do Sul). — Peru- 
gia, Ann. Mus. Genova, (2J, X, 1891, 630 (Rio Durazno; Rio de La Plata; 
Paraguay; Parana; Montevideo; Buenos Aires). — von Ihering, Slisswasser- 
fische Rio Grande do Sul, 1893, 17.— Lahille, Rev. Mus. la Plata, VI, 1895, 
271 (very abundant every where in La Plata) . — Boulenger, Boll. Mus. Zool. 
ed Anat. Comp. Torino, XII, 1897 (Mission San Francisco). — Perugia, Ann. 
Mus. Genova, (2), XVIII, 1897, 149,— (Puerto 14 de Mayo).— Pellegrin, 
Bull. Mus. d'Hist. Nat., V, 1899, 157 (Apure).— Vaillant, Nouv. Arch. Mus. 
d'Hist. Nat. (4), 1900, 124 (Carsevenne, French Guiana). — Steindachner and 
von Bayern, Denkschr. Akad. Wiss. Wien, LXXII, 1902, 135. — Eigenmann and 
Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 668 (Amazon) ; Eigenmann, Ann. 
Carnegie Mus., IV, 1907, 115 (Porto Murtinho; Bahia Negra; Corumba). 

Pimelodus rigidus Agassiz, Selecta Gen. et Spec. Bras., 1829, 19, pi. 7, fig. 2. 

Pimelodus blochii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 188 
(Cayenne; (Surinam). 

Paramutana blochii Gunther, Catalogue, V, 1864, 111 (copied). — Vaillant, Bull. 
Soc. Philom., (7), IV, 1880, 152 (Calderon). 

? Pimelodus arekaima Schomburgk, Fishes Brit. Guiana, I, 1841, 178, plate, not 
descr. (Essequibo). 

Mystus ascita Gronow, Cat. Fish, ed. Gray, 1854, 156 (based on Mus. Ichth., I, 
1754, 35; Zoophyl, I, 1763, 125, No. 385). - 

Pimelodus schomburgkii Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 208 (for 
B. maculatus Schomburgk). 

Pseudorhamdia ascita Bleeker, Versl. en Med. Acad. Wet. Amsterdam, XIV, 
1862, 384 (Surinam). 

Pimelodus macronema Bleeker, " Silures de Suriname," 1864, 79, pi. 14 (Surinam). 

Pseiidorhamdia piscatrix Cope, Proc. Am. Philos. Soc, XI, 1870, 569 (Pebas); 
Proc. Acad. Nat. Sci. Phila., 1872, 262 (Ambyiacu River) ; Proc. Am. Philos. 
Soc, XVII, 1878, 674 (Peruvian Amazon). 

Pseudariodes pantherinus Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 
192, 199 (Venezuela). 

Pseudariodes albicans Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 194, 
198, not Aims albicans Valenciennes (La Plata and its tributaries). — Stein- 
dachner, " Fisch-Fauna Magdalenen-Stromes," 1878, 61, note. 

Piramutana macrospila Gunther, Ann. and Mag. Nat. Hist. (5), VI, 1880, 10, 
pi. 2 (Rio Plata). 



174 MEMOIRS OF THE CARNEGIE MUSEUM 

The following is a general description, applicable to all the varieties. 

Head 3.75-3.85; depth 4-4.2; D. 1,6; A. 12 or 13. 

Top of head, occipital process, dorsal plate and humeral process granular; 
profile steep, rising with more or less of an angle from the base of the occipital 
process. Dorsal spine striate on the sides, with weak retrorse teeth near its tip on 
the anterior margin; posterior margin with a few similar hooks near the tip; spine 
about equal to the head in length, the last ray two-fifths the length of the spine. 
Base of dorsal slightly greater than its distance from the adipose, which is slightly 
longer than the dorsal; its height 2.5 in its length. Upper caudal lobe two-fifths 
longer than the lower; anal emarginate; pectoral spine striate above and below, 
its outer margin nearly smooth in the adult, retrorse spines along its inner margin. 
Humeral process broad, obliquely truncate behind, not spine-like. 

The following varieties were collected. 



One specimen, 98 mm. (maxillary barbel 115). Koriabo Rubber Plantation. 
(C. M. Cat. No. 1617.) 

One specimen, about 127 mm. (maxillary barbel 150). Issorora Rubber Planta- 
tion. (I. U. Cat, No. 12009.) 

Ten specimens, 53-68 mm. Creek in Mora Passage. (C. M. Cat. No. 1683 
a-d; I. U. Cat. No. 12059.) 

One specimen, 238 mm. (maxillary barbel 270). Lama Stop-Off. (C. M. Cat. 
No. 1608.) 

Here belongs also the macronema of Bleeker. 

Maxillary barbel extending beyond tip of caudal; vomerine teeth present; 
upper caudal rays 2.5 in the length; eye 1-1.4 in the interorbital. 

Ashy, lateral line light; no spots. 

B. 

Four specimens, 115-253 mm. (maxillary barbel 133-238). Wismar. (C. M. 
Cat. No. 1609; I. U. Cat. No. 12010.) 

Three specimens, about 67-108 mm. (maxillary barbel 138). Locality ? (C. M. 
Cat. No. 1610; I. U. Cat. No. 12011.) 

114 specimens, 50-173 mm. Bartica Sand-bank. (C. M. Cat. No. 1611a-i; 
I. U. Cat. No. 12012.) 

Two specimens, 92 (maxillary barbel 100) to about 96 mm. (maxillary barbel 
100). Rockstone. (C. M. Cat. No. 1612; I. U. Cat. No. 12013.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 175 

Two specimens, 89-93 mm. (maxillary barbel 110-115). Crab Falls. (C. M. 
Cat. No. 1613; I. U. Cat. No. 12014.) 

Two specimens, 111 mm. to base of lower caudal lobe. Rupununi. (C. M. 
Cat. No. 1614; I. U. Cat. No. 10215.) 

Vomerine teeth present; upper caudal lobe 2.66 in the length; eye greater 
than interorbital to 1.5 in interorbital; color in young ashy to below the lateral 
line, lateral line and a narrower line half-way between it and the back light, the 
dark streak below the lateral line breaking into spots at times, the light line on the 
upper part of the sides becoming irregular; a dark predorsal spot; a darker streak 
along humeral spine to above the ventral; dorsals spotted; color especially bright 
in Nos. 1614 C. M. Cat. and 12015 I. U. Cat.; color of adult uniform ashy, without 
spots. 

A single small specimen, 50 mm. long, from Tumatumari, probably belongs 
here. 

Two specimens, 275 (maxillary barbel 171, not reaching to caudal)-330 mm. 
(maxillary barbel 235, reaching to caudal). Botanic Gardens. (C. M. Cat. No. 
1615; I. U. Cat. No. 12016.) 

Five specimens, 190-172 mm. Lama Stop-Off. (C. M. Cat. No. 1616; I. U. 
Cat. No. 12017.) 

Steel-blue, with light reticulations breaking the blue into small spots; lateral 
line white. 

Maxillary barbel usually not reaching the caudal. Eye 1.5 in interorbital. 

48. Pimelodus ornatus Kner. 

Pimelodus ornatus Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 411, fig. 18 
(Surinam; Rio Negro; Cujaba). — Gunther, Catalogue, V, 1864, 116 (River 
Capin, Para).— Peters, MB. Akad. Wiss. Berlin, 1877, 470 (Calabozo) — 
Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 134 (Goyaz). — 
Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 499 (Asuncion; 
Arroyo Trementina). — Eigenmann, Ann. Carnegie Mus., IV, 1907, 115 
(Corumba); Repts. Princeton Univ. Exp. Patagonia, III, 1910, 388. 

Pseudorhamdia ornata Bleeker, " Silures de Suriname," 1864, 77 (Surinam). 

Silurus megacephalus (ex Natterer, MS.) Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 
413. 
Five specimens, 140-283 mm. Creek below Potaro Landing. (C. M. Cat. No. 

1618a and 6; I. U. Cat. No. 12018.) 

Twenty-six specimens, 45-167 mm. Tumatumari. (C. M. Cat. No. 1619a- 

e; I. U. Cat. No. 12019.) 



176 MEMOIRS OF THE CARNEGIE MUSEUM 

Three specimens, 114-144 mm. Rockstone. (C. M. Cat, No. 1620; I. U. Cat. 
No. 12020.) 

One specimen, 55 mm. Crab Falls. (C. M. Cat. No. 1621.) 

Head 3.3-3.5; depth 4.4-5.5; D. 1,6; A. 12-13. 

Profile nearly straight, interorbital slightly depressed; surfaces of head covered, 
scarcely granular in the adult, Dorsal spine slender, smooth or slightly rough in 
front, not quite equal to snout and eye; last dorsal ray about half the length of 
the highest, the spine not reaching beyond the middle of the last ray when depressed, 
usually shorter; base of dorsal a little greater than its distance from the adipose, 
which is longer than the dorsal; caudal lobes slender, the upper 3.5-4 in the length; 
posterior margin of anal subtruncate; pectoral spine about equal to the snout, 
with antrorse teeth in front and retrorse teeth behind. Maxillary barbel reaching 
to base or to tip of caudal, post-mental to middle of pectoral; no teeth on the 
vomer; humeral process spine-like. Dorsal with a conspicuous black blotch near 
the middle of the front half of the fin; a light streak from dorsal spine to above 
ventral and then back to the middle caudal rays, and above this again another 
light streak. 

49. Pimelodus heteropleurus sp. nov. (Plate XVI, fig. 2.) 

Type unique, 46 mm. Rupununi Pan. (Carnegie Museum Catalog of Fishes 
No. 1734.) 

Head 4; depth 5.3; D. 1,6; A. 11; adipose 4 in the length; eye 3.3 in the 
length, but little shorter than the snout, one-fourth longer than width of interorbital. 

Form of Pimelodus clarias, the occipital process narrow at its base, scarcely 
tapering to its tip, which just reaches the dorsal plate; fontanel not quite reaching 
to the posterior margin of the eye, a bridge over the middle of the eye, the part 
back of it narrower, not continued as a groove; jaws equal, the teeth in bands of 
equal width in the two jaws; maxillary barbels reaching a little beyond middle of 
adipose, outer mental barbel just beyond base of pectoral. 

Dorsal spine slender, equal to head without snout in length, about equal to 
the distance between the dorsals; anal rounded; ventrals not reaching anal; pec- 
toral spine a little longer than the dorsal spine, rough in front, with retrorse teeth 
behind which increase in size to the middle of the spine, where they cease abruptly; 
humeral process spine-like. 

Sides punctate, the chromatophores in the median area between the dorsal 
and anal gathered along the septa; a median series of chromatophores along the 
sides; back along base of dorsal and between the dorsals dark. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 177 

50. Pimelodus altipinnis Steindachner. 

Pimelodus altipinnis Steindachner, " Icthyologische Notizen," i, 1864, 14, pi. 2, 
figs. 3 and 4 (Demerara) ; " Icthyologische Beitrage," iv, 1876, 55, pi. 11 (Para; 
Santarem; Cameta). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., 
(2), 1, 1888, 135 (Para); Occasional Papers Cal. Acad. Sci., I, 1890, 180 (Para). 
— Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 388 — 
? Perugia, Ann. Mus. Genova, (2), XVIII, 1897, 18 (Rio Beni).— Eigen- 
mann and Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 660 (Amazon). 
The type of this species came from Demerara. It is 86 mm. long. No speci- 
mens were secured by me. The species has the general characters of a Pimelodella, 
and it would not be surprising if the small type in the Vienna Museum should 
prove to be a Pimelodella and distinct from the specimens subsequently referred to 

the same name. 

Gceldiella Eigenmann and Norris. 

Goeldiella Eigenmann and Norris, Rev. Mus. Paulista, IV, 1900, 353 (eques). 

Type, Pimelodus eques Miiller and Troschel. 

This genus differs from the related genera Pimelodus and Pimelodella in the 
character of the caudal fin, which is unequally lobed. 

51. Goeldiella eques (Miiller and Troschel). 

Pimelodus eques Muller and Troschel, in Schomburgk, Reisen, III, 1848, 628 (all 
rivers of Guiana); Horse Ichth., Ill, 1849, 5 (Guiana). — Gunther, Catalogue, 
V, 1864, 116 (copied). — Steindachner, "Icthyologische Beitrage," v, 
1876, 99 (Amazon near Fonteboa; Teffe; Obidos; Villa Bella; Jose Fernandez; 
XingujTonantins; Hyutahy; Lake Hyanuary ) . — Eigenmann and Eigenmann, 
Proc. Cal. Acad. Sci., (2), 1888, 134 (localities given by Steindachner); Occa- 
sional Papers Cal. Acad. Sci., I, 1890, 166; Proc. U. S. Nat. Mus., XIV, 1891, 
29.— Pellegrin, Bull. Mus. d'Hist, Nat., V, 1899, 405 (Manaos). 

Goeldiella eqties Eigenmann and Norris, Rev. Mus. Paulista, IV, 1900, 353. — 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 388. 
Eleven specimens, 91-148 mm. Rupununi. (C. M. Cat. No. 1606o-c; I. U. 

Cat. No. 12008.) 

One specimen, 205 mm. Rockstone. (C. M. Cat. No. 1607.) 

Head 3.5-3.75; depth 4.75-5.25; D. 1,6; A. 10 or 11. 

Profile in front of dorsal nearly straight, lower outline nearly straight from 

caudal to below eye; interorbital flat; bones of the head from the nares to the 

dorsal plate and the dorsal plate with reticulated ridges; occipital fontanel a 

narrow slit in specimens up to a length of at least 150 mm. 



178 MEMOIRS OF THE CARNEGIE MUSEUM 

Eye 4.5-5.5, 1.3-1.5 in interorbital, somewhat behind the middle of the head; 
premaxillary teeth in a narrow band of the same width throughout. Maxillary 
barbel extending to the middle of the caudal or farther, post-mental not quite to 
tip of pectoral. 

Dorsal spine with retrorse notches in front, roughened behind, about equal 
to snout and eye in length; pectoral spine strong, striate above and below, with 
antrorse teeth in front and retrorse teeth behind; adipose fin nearly or quite half 
as long as the body without the head; caudal peduncle half as high as long. 
Caudal slightly notched, the upper lobe shorter than the lower, projecting for 
about one-fourth of its length beyond the fork. 

A dark saddle downward and forward from front of dorsal, covering nearly 
the entire opercle; an irregular mottled dark band along the lateral line and just 
below it; base of caudal dark, the fins irregularly mottled. Lower surface white. 

Phractocephalus Agassiz. 

Phractocephalus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 22 (bicolor = 

hemilopterus) . 

Large. Vomer with a large pentagonal patch of teeth in contact with the 
palatine patches. Occipital process large, semicircular, not meeting the reniform 
dorsal plate. Upper half of adipose usually rayed. Barbels subterete. Caudal 
forked; head as broad as long. 

Type, Silurus hemiliopterus Bloch and Schneider. 

52. Phractocephalus hemiliopterus (Bloch and Schneider). 

Silurus hemiliopterus Bloch and Schneider, Syst. Ichth., 1801, 385. 

Phractocephalus hemiliopterus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 
1840, 3, pi. 421. — Schomburgk, Fishes Brit. Guiana, I, 1841, 169 (Guiana, 
everywhere). — Muller and Troschel, in Schomburgk, Reisen, III, 1849, 643 
(all rivers of Guiana). — Castelnau, Anim. Am. Sud, Poiss., 1855, 47, pi. 15, 
fig. 4 (Rio Crixas; Araguay; Amazon). — Gunther, Catalogue, V, 1864, 110 
(River Cupai).— Vaillant, Bull. Soc. Philom., (7), IV, 1880, 152 (Calderon).- 
CoPE,Proc. Am. Philos. Soc, XVII, 1878, 674 (Peruvian Amazons). — Eigen- 
mann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 135 (Xingu; Coary; 
Teffe; Manacapuru; Obidos; Lake Hyanuary); Occasional Papers Cal. Acad. 
Sci., I, 1890, 188. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 390. 

Phractocephalus bicolor Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 23 (Amazon). 



eigenmann: the FRESHWATER PISHES OF BRITISH GUIANA 179 

Pirarara bicolor Spix, Gen. Spec. Pise. Bras., 1829, 23 (Amazon). 

No specimens of this species were preserved. Parts of a head were seen in 
the Georgetown market. Schomburgk states that it reaches a length of four feet 
and is "common to all rivers." The description is takan from Eigenmann and 
Eigenmann. 

Head 3.33; depth 4.75; Br. 9; D. 1,7; A. 9; eye 9 in head, 3 in snout, 5 in inter- 
orbital, 2 diameters behind the rictus. 

Body rapidly tapering towards caudal; head heavy, broad, flattened between 
the eyes; greatest width of the head equals its length; width at the angle of the 
mouth 2 in its length. 

Maxillary barbel on edge of lip, opposite anterior nostril, reaching beyond the 
tips of the pectoral fin; mental barbels two-thirds to one-half as long as post- 
mental barbels, which reach the pectoral. Lower jaw included; teeth all alike, 
those on the intermaxillaries in a broad band of equal depth throughout; vomerine 
teeth in a much broader patch; palatine teeth in narrower, wedge-shaped patches 
contiguous to the vomerine patch. Gill-membranes separate to below anterior 
margin of the eye. Gill-rakers short and fleshy, 4 + 15. Bones behind eye 
variously grooved and granulated; the occipital process broadly rounded behind, 
not meeting the reniform dorsal plate. 

Dorsal spine midway between snout and tip of adipose dorsal, and between 
bases of pectoral and ventral fins; last dorsal ray over base of ventral, the length 
of the spine 2.25 in head. 

Adipose dorsal short, high, its upper portion generally transformed into true 
rays; its base longer than that of the anal. 

Caudal broad, slightly emarginate. The rays of the dorsal and caudal thick 
and terete, once or twice branched. Ventrals extending for half their length 
beyond the vent. 

Pectoral spine two or three times as thick as the dorsal spine, broad lamellae 
in front and sharp recurved teeth behind; its length 2 in the head. 

Between pectorals and anal dark brown; lower part of head, a narrow band 
above pectorals and along sides, spreading over the lower three-fourths of the tail, 
white (yellow in life), region above this brownish; a round white spot on each side 
of dorsal spine; orbit bordered with white above, head and ante-dorsal region with 
darker spots or vermiculations; sometimes all of the lower parts are white. 

Brachyplatystoma Bleeker. 

Platystoma Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, -- (sp.). 
Brachyplatystoma Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (vaManti). 



180 MEMOIRS OF THE CARNEGIE MUSEUM 

Piratinga Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 100 (reticulata). 
Malacobagrus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 100 (filamentosus). 

Type, Platystoma vaillanti Cuvier and Valenciennes. 

Vomer and palate with villiform teeth; inner teeth of the jaws slender and 
freely movable; caudal forked; head covered with skin; occipital process short, 
concealed, not reaching the dorsal in the adult. 

53. Brachyplatystoma vaillanti (Cuvier and Valenciennes). (Plate XVII, fig. 3.) 

"Laulau." 

Platystoma vaillanti Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 21, pi. 
423 (Cayenne and Surinam) .— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 397 
(Para). — Gunther, Catalogue. V, 1864, 108 (Demerara). — Peters, MB. Akad. 
Wiss. Berlin, 1877, 469 (Calabozo). 
Brachyplatystoma vaillanti Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (name 
only) ; ' ' Silures de Suriname, ' ' 1 864, 70 (Surinam) . — Eigenm ann and Eigenmann, 
Proc. Cal. Acad. Sci., (2), 1, 1888, 136 (Tabatinga; Para; Porto do Moz; Arary; 
Rio Puty; Juiz de Fora); Occasional Papers Cal. Acad. Sci., I, 1890, 196. — 
Eigenmann and Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 662 (Amazon).— 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 390. 
Platystoma affine Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 24 
(Brazil). — Castelnau, Anim. Am. Sud, Poiss., 1855, 40 (Araguay).— 
Gunther, Catalogue, V, 1864, 109 (copied). 
I have examined the specimen mentioned by Bleeker and: 
One specimen, head only. Rockstone. (C. M. Cat. No. 1288.) 
Sixteen specimens, 178-290 mm. to tip of middle caudal rays. Georgetown 
market. (C. M. Cat. No. 170a-d; I. U. Cat, No. 12083.) 

Head 3.4-3.5; depth 5.5; D. 1,6; A. 13; eye 4 in snout; 10 in head, 2.5 in 
interorbital in a specimen 280 mm. long to tip of middle caudal rays, 4 in snout, 
9 in head, and 2.5 in interorbital in a specimen 178 mm. long to tip of middle 
caudal rays; adipose fin 4.4-4.5 in the length. 

Subtriangular in section at the dorsal fin, the snout much depressed, the tail 
moderately compressed; occipital crest narrow, not much tapering, its width near 
the middle one-fourth its length in the Georgetown specimens, reaching but not join- 
ing the dorsal plate. An elongate depression along middle of the head ; fontanel nar- 
row, extending to the posterior margin of the eye; mouth lunate from below, the 
upper jaw scarcely projecting ; maxillary barbel extending beyond tip of middle 
caudal rays in all the Georgetown specimens; mental barbels opposite angle of 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 181 

mouth, the post-mentals reaching beyond the ventrals. Dorsal and anal emar- 
ginate, the first ray in each reaching beyond the tip of the last; dorsal and pectoral 
spines slender, with recurved hooks on the posterior margin, most marked toward 
the tip; pectoral and ventral falcate; caudal deeply forked, the outer rays normally 
about 4 times as long as the middle ones, but prolonged in the young to equal the 
length from snout to caudal. 

Pale below, darker above. 

The young of this species can be readily distinguished by its long barbels 
and prolonged caudal tips. 

Hemisorubim Bleeker. 

Platystoma Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 27 (sp.), pre- 
occupied in Diptera. 
Hemisorubim Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (platyrhynchos). 
Type, Platystoma platyrkynchos Cuvier and Valenciennes. 
Upper jaw thin and truncate, shorter than the lower jaw; snout narrowed; the 
width at the angle of the mouth 1.5 times in the greatest width of the head; mental 
barbels approximate and near the edge of the lip; premaxillary band of teeth much 
shallower at the middle than at the ends; the palatine patches large. Occipital 
process shorter than the dorsal plate and meeting it; postorbital portion of the 
head striate and granulate; skin on the sides of the head and snout reticulate. 

54. Hemisorubim platyrhynchos Cuvier and Valenciennes. 

Platystoma platyrhynchos Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 
27 (no locality). — MtJLLERand Troschel, in Schomburgk, Reisen, III, 1848, 
628 (Rupununi). — Castelnau, Anim. Am. Sud, Poiss., 1865, 40 (Amazon).— 
Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 398 (Barra do Rio Negro). 

Hemisorubim platyrhynchos Bleeker, Nederl. Tijdschr. Dierk., I, 1863,97 (name 
only). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 138 
(Manacapuru; Rio Negro; Montalegre; Rio Puty; Lago Alexo; Obidos; Coary; 
Tabatinga; Hyavary; Tonantins; Sao Paolo) ; Occasional Papers Cal. Acad. 
Sci., I, 1890, 206.— Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 390. 

Hemisorubim platyrhynchus Gunther, Catalogue, V, 1864, 109 (copied). — Peters, 
MB. Akad. Wiss. Berlin, 1877,470 (Calabozo).— Cope, Proc. Am. Philos. Soc, 
XVII, 1878, 674 (Peruvian Amazon).— Vaillant, Bull. Soc. Philom., (7), IV, 
1880, 152 (Calderon). 
No specimens of this species were obtained. 



182 MEMOIRS OF THE CARNEGIE MUSEUM 

I have been able to examine a specimen collected by Schomburgk and now 
in the Berlin Museum. 

Head 3; depth 6-7; D. 1,6; A. 10; Br. 11; eye 7 in head, 3 in snout, 1.75 
in interorbital. 

Head depressed, rounded on occiput; eye directed largely upward. Lower 
jaw projecting and entering profile. Maxillary barbels extending past dorsal fin; 
mental barbels approximate, extending to below eyes; post-mentals to pectorals. 
Teeth in the lower jaw in a narrow band. Vomerine and palatine teeth close 
behind the premaxillary teeth, the vomerine teeth in a single patch separate from 
the palatine patches. 

Dorsal spine weak and slender, 2.5 in head, its distance from the snout greater 
than its distance from the posterior margin of the adipose fin, much nearer base 
of ventrals than base of pectorals; with retrorse teeth behind. Adipose fin longer 
than anal. Lower caudal lobe wider and longer than upper, rounded in adult, 
pointed in young. Ventrals extending two-fifths their length beyond the vent. 
Pectoral spine 1.6 in head, usually with equally strong teeth in front and behind. 

White below, olivaceous above, with a few jet-black spots scattered on sides, 
and usually a similar spot at base of upper caudal lobe; fins plain. 

Pseudoplatystoma Agassiz. 

Platystoma Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 23 (sp.). 
Sorubim Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pis. 12-15 (sp.). 
Pseudoplatystoma Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (fasciatum). 
Hemi-platystoma Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 (tigrinum). 

Type, Silurus fasciatus Linnseus (in part). 

Upper jaw little longer than lower; teeth of the jaws alike; vomerine and 

palatine patches of teeth more or less united, the two forming a comma-shaped 

patch on each side of the palate; gill-rakers short, spine-like, not overlapping; 

caudal deeply lobed, the lobes rounded (except in very young), the rays very much 

branched, giving the fin a leathery texture. Branchiostegals 14 or 15; barbels 

short. 

55. Pseudoplatystoma fasciatum (Linnseus). 

Tiger-fish. 

Silurus fasciatus Linnaeus, Syst, Nat., ed. 12. I, 1766, 505.— Gmelin, Syst. Nat., 
I, iii, 1788, 1359.— Bonnaterre, Tabl. Enc. Meth., Ichth., 1788, 154,252.- 
Bloch, Ausl. Fische, VIII, 1794, 30, pi. 366.— Bloch and Schneider, Syst. 
Ichth., 1801,382. 



EIGENMANM : THE FRESHWATER FISHES OF BRITISH GUIANA 183 

Pimelodus fasciatum Lacepede, Hist. Nat. Poiss., V, 1803, 94, 99, 100. 

Platystoma fasciatum Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 14 
(copied).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 401 (Surinam).- 
Gunther, Catalogue, V, 1864, 107 (Essequibo; Surinam; River Capin, Para).— 
Peters, MB. Akad. Wiss. Berlin, 1877, 469 (Calabozo). — Steindachner, 
"Fisch-Fauna Magdalenen-Stromes," 1878, 15 (Magdalena River). — Cope, 
Proc. Am. Philos. Soc., XVII, 1878, 674 (Peruvian Amazon). — Stein- 
dachner, ''Fisch-Fauna des Cauca," etc., 1880, 5 (Cauca); "Icthyologische 
Beitrage," viii, 54 (Surinam); "Flussfische Stidamerika's," iv, 1882, 4 (Rio 
Amazonas ; Iquitos) . 

Pseudoplaty stoma fasciatimi Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 97 
(name only); "Silures de Suriname," 1S64, 72 (Surinam). — Eigenmann 
and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 138 (Obidos; Coary; 
Hyavary); Occasional Papers Cal. Acad. Sci., I, 1890, 208.— Steindachner 
and von Bayern, Denkschr. Akad. Wiss. Wien, LXXII, 1902, 136 (Rio 
Lebrija, Colombia). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 
III, 1910, 39. 

Platystoma truncation Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 27, pi. 13a 
(Rio Japura and Solimoens). — Cuvier and Valenciennes, Hist. Nat. Poiss., 
XV, 1840, 20 (Brazil).— Hyrtl, Denkschr. Akad. Wiss. Wien, XVI, 1859, 
17 (vertebra? 13 + 33).— Gunther, Catalogue, V, 1864, 108 (copied). 

Platystoma tigrinum (not of Cuvier and Valenciennes) Schomburgk, Fishes Brit. 
Guiana, 1, 1841, 185 (most of the rivers). — Muller and Troschet., in Schom- 
burgk, Reisen, III, 1848, 627 (nearly all rivers). 

Platystoma punctifer Castelnau, Anim. Am. Sud, Poiss., 1855, 40, pi. 19, fig. 2 
(Amazon). 
Four specimens, 245-295 mm. Rupununi Pan. (C. M. Cat. No. 1699a; I. U. 

Cat. No. 12082.) 

One specimen, 455 mm. Wismar. (C. M. Cat. No. 1295.) 

Head 2.66-2.75; depth 6.5-7.25; D. 1,6; A.ll-14; eye 6 in snout, 12 in head, 2.5 

in interorbital. 

Snout much depressed; body slender, subterete at the dorsal; groove of the 

fontanel not continued to the occipital process; a deep groove across the head at 

base of the occipital process; maxillary barbel reaching to near tip of dorsal. 

Dorsal spine nearer tip of adipose than to tip of snout. 

Dark brown above, abruptly white on the lower part of the sides; about ten 

black cross-bands, margined with white in front; some dark spots along the line of 



184 MEMOIRS OP THE CARNEGIE MUSEUM 

the lower ends of the bars; vertical fins, and sometimes tips of ventrals, spotted. 
The specimen in the Leiden museum mentioned by Bleeker agrees with the above. 

Subfamily Doradin^e. 

Doras Lacepede. 17 

Doras Lacepede, Hist. Nat. Poiss., V, 1803, 116 (carinatus and costatus) — Cuvier 

and Valenciennes, Hist. Nat. Poiss., XV, 1840, 267 (costatus). 
Centrochir Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 14 (crocodili). 
Lithodoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 84 (lithog aster) . 
Pterodoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 84 (granulosus). 
Platydoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 86 (costatus) = Doras 

Cuvier and Valenciennes. 
Acanthodoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 86 (cataphr actus) . 
Astrodoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 86 (asterifrons) . 
Amblydoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 86 (affinis). 
Zathorax Cope, Proc. Acad. Nat. Sci. Phila., 1872, 271 (monitor) = Astrodoras 

Bleeker. 
Agamyxis Cope, Proc. Amer. Philos. Soc, XVII, 1878, 101 (pectinifrons) . 

Type, Silurus costatus Linnseus. 

Doradines with anterior nares on or near the upper lip ; the snout short, the eye 
in anterior half of the head; teeth well-developed; adipose fin usually with a well- 
defined anterior margin. 

Key to the Species of Doras. 

a. Caudal forked; dorsal spine serrate in front and behind, the serrae of the anterior margin antrorse. 
Sides of dorsal spine with striations (Doras). 
6. Plates of the sides increasing in height to the caudal peduncle, the highest about .4 the height of 
the peduncle; caudal peduncle naked above and below, spotted, without lateral bands. 

granulosus. 

66. Plates of sides decreasing in height regularly from the dorsal to the caudal, not meeting along a 

median line above or below; caudal peduncle with a series of plates above and below. 

Slate-colored above, with a yellow band from the fontanel along the sides to the tip of the 

middle caudal rays; ventral surface without ossifications costatus. 

aa. Caudal very slightly emarginate or rounded; dorsal spine without serrations either in front or behind, 
the sides of the spine with smooth striations; plates of the sides decreasing in height from the 
dorsal to the caudal, not meeting above and below; caudal peduncle largely naked above and 
below, the caudal fulcra continued about half-way to adipose and anal fins; chocolate brown with 
an irregular dark band below the median hooks of the lateral plates, and other darker blotches; 

nuchal region roof -shaped. (Amblydoras) hancocki. 

17 Doras maculatus Valenciennes, Miiller and Troschel, in Schomburgk, Reisen, III, 1S48, 629 (Esse- 
quibo). 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 185 

aaa. Caudal rounded; dorsal spine with a series of straight teeth along its anterior margin, its sides with 
a regular or several irregular (in old), series of straight teeth, its posterior margin without teeth; 
plates of sides of about the same height from dorsal to anal, those of opposite sides meeting along 
the median line on upper and lower surfaces of the caudal peduncle of the adult; a narrow light 
line from the upper margin of the eye to the caudal; a light line from dorsal spine forward to the 
fontanel; nuchal region broadly rounded. (Acanthodoras) cataphractus. 

56. Doras granulosus Valenciennes. (Plate XVII, fig. 4.) 

Doras granulosus Valenciennes, in Humboldt, Rec. Obs. Zool., II, 1811, 184.— 

Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 392. 
Pterodoras granulosus Bleeker, Nedeii. Tijdschr. Dierk., I, 1863, 15 (name only) 

" Silures de Suriname," 1864, 36 (Surinam). 
Doras maculatus Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 7, 
pi. 5, fig. 3. — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 281 
(Buenos Ayres). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 
629.— Steindachner, Denkschr. Akad. Wiss. Wien, XLI, 1879, 47 (Rio de la 
Plata). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sei., (2), I, 1888, 150 
(Arary?); Occasional Papers Cal. Acad. Sci., I, 1890, 229 (Arary ?; Uruguay; 
Buenos Aires, Serfa). 
Doras murica (ex Natterer, MS.) Kner, SB. Akad. Wiss. Wien, XVII, 1885, 129 

(Cujaba). 
Doras muricus Gunther, Catalogue, V, 1864, 202 (Demerara ?) . 

No specimens were secured. I have examined a specimen about 395 mm. 
long collected by Schomburgk in Guiana. 

Head 4, depth about 4; D. 1,6; A. 11; plates 35; eye 3.5 in the snout, 10 
in the head, 3.5 in the interorbital. 

Lateral plates beginning on the vertical from just in front of the dorsal, the 
twelfth about equal to the eye in height, the highest on the caudal peduncle .4 
the height of the peduncle, with a median but no lateral spines. Dorsal spine 
nearly as long as the head, the spines of the posterior margin much longer than 
those of the anterior; pectoral spine longer than the head, its posterior spines about 
twice as long as its anterior; caudal forked, the lower lobe longer. Humeral spine 
very slender, reaching to below the dorsal spine. Maxillary barbel reaching to the 
tip of the pectoral ; free margin of the nasal plate but little pectinate. 
Chocolate, marbled; the fins spotted. 

57. Doras costatus (Linnaeus). 

Silurus costatus Linnaeus, Syst. Nat., ed. 12, I, 1766, 506. 
Cataphractus costatus Bloch, Ausl. Fische, VIII, 1794, 82, pi. 376. 



186 MEMOIRS OF THE CARNEGIE MUSEUM 

Doras costatus Lacepede, Hist. Nat. Poiss., V, 1803, 116, part (South Amer- 
ica). — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 268 (Guiana). — 
Castelnau, Anim. Am. Sud, Poiss., 1855, 48 (Amazon). — Gunther, Cata- 
logue, V, 1864, 201 (British Guiana; River Cupai). — Eigenmann and Eigen- 
mann, Proc. Cal. Acad. Sci., (2), I, 1888, 161 (Rio Preto; Rio Puty; San Gon- 
callo ; Xingu Cascade ; Obidos ; Gurupa ; Teffe) ; Occasional Papers Cal. Acad. Sci. , 
I, 1890, 231.— Perugia, Ann. Mus. Genova, (2), 1891, 34 (Villa Maria, Para- 
guay). — Kindle, Ann. N. Y. Acad. Sci., VIII, 1895, 251 (Trocera on the Tocan- 
tins). — Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903,500 (Para- 
guay). — Eigenmann, Ann. Carnegie Mus., XXXI, 1907, 1 16 (Corumba; Laguna 
Ipacarai); Repts. Princeton Univ. Exp. Patagonia, III, 1910, 393. 
Platydoras costatus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 16 (name only); 

" Silures de Suriname," 1864, 38 (Surinam). 
Doras cataphractus (not of Linnaeus) Schomburgk, Fishes Brit. Guiana, I, 1841, 

158 (Rio Negro). 
Doras armatidus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 629 
(Rupununi; Awaricura). 

Two specimens, 105 and 108 mm. Twoca Pan. (C. M. Cat. No. 1638; I. U. 
Cat. No. 12030.) 

Four specimens, 75-90 mm. Gluck Island. (C. M. Cat. No. 1639; I. IT. Cat. 
No. 12031.) 

One specimen in the Berlin Museum from Guiana and two from Calabozo. 
Head 3.75; depth 4.25; D. 1,6; A. 11; lateral plates 2 + 30 or 31. Eye 
1.66-2 in snout, 4-5 in head; 1.5-2 in interorbital. Ventral surfaces of coracoid 
not exposed. Width at tip of humeral processes greater than the depth; nuchal 
region bluntly roof-shaped. Head granular to in front of posterior nares; nasal 
bone with blunt serration, scarcely raised; orbit with granular margin; maxillary 
barbel reaching to tip of humeral process, outer mental to base of pectoral. 18 Upper 
jaw longer; width of mouth less than half the distance between the gill-openings. 
Pectoral spine striate above and below, strongly serrate in front and behind, reach- 
ing beyond base of ventrals; dorsal spine shorter than pectoral spine, its sides 
striate, serrate on its anterior and posterior margin, the serrse on the posterior 
margin much smaller; teeth on front margin of dorsal spine antrorse; largest near 
the tip; humeral process reaching to fourth fifth of the pectoral spine; caudal 
forked; height of highest lateral plate about half the length of the head, each plate 
with numerous small backward-directed spines, in several vertical rows in front, 

18 To its middle in the larger specimen at Berlin. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 187 

in a marginal row behind; median spines strong, recurved; caudal peduncle entirely 
covered with a median series of plates above and half-way to the anal below. 

Slaty blue, a light band from the fontanel along the middle to the tip of the 
caudal; lower surface and margin of head to near the eye light. Barbels dark, 
dark streak back from the maxillary barbel; dorsal with a dark band across its 
upper part; center and margins of caudal light, a pair of submarginal dark bands; 
anal with a dark streak; ventrals hyaline; pectoral dusky. 

58. Doras hancocki ( luvier and Valenciennes. 
" Saurauwari," "Yarauira." 
Doras costata (not of Linnseus) Hancock, Zool. Journ., IV, 1828, 242 (Demerara).— 

Schomburgk, Fishes Brit. Guiana, I, 1841, 156. 
Doras hancockii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 279.— 

Gunther, Catalogue, V, 1864, 202 (Demerara; Rio Cupai). — Eigenmann and 

Eigenmann, Occasional Papers Cal. Acad. Sci., I, 1890, 234. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 393. 

One hundred and ninety-five specimens, 9-120 mm. Lama Stop-Off. (C. M. 
Cat. No. 1443a-t; I. U. Cat. No. 12033.) 

Ten specimens, 65-123 mm. Maduni Creek. (C. M. Cat. No. 1444a-6; 
I. U. Cat, No. 12034.) 

One specimen, 28 mm. Wismar. (C. M. Cat, No. 1445a). 

Nine specimens, 26-41 mm. Rockstone. (C. M. Cat. No. 1446a-6; I. U. 
Cat, No. 12035.) 

Twelve specimens, 28-36 mm. Gluck Island. (C. M. Cat, No. 1649a-6; 
I. U. Cat. No. 12038.) 

Four specimens, 68-98 mm. Tumatumari. (C. M. Cat. No. 1447a; I. U. 
Cat, No. 12036.) 

Eight specimens, 30-45 mm. Rupununi Pan. (C. M. Cat. No. 1448a-6; 
I. IT. Cat, No. 12037.) 

Head 4-4.3; depth 4.25; width at tip of humeral process 3.66; D. 1,6; A. 11- 
13; lateral plates 1 + 25; eye 1.5 in snout, 4.5 in head. 1.5 in interorbital. 

Coracoid and its process exposed below, striate; nuchal area with a blunt 
median keel, roof-shaped; head granular to the anterior nares; movable nasal bone 
large, forming part of the orbit ; maxillary barbel reaching tip of humeral process, 
outer mental barbel to its middle; jaws equal, mouth terminal, its width less than 
half the space between the gill-openings. 

Pectoral spine strongly serrate on its anterior and posterior margins, its upper 



188 MEMOIRS OF THE CARNEGIE MUSEUM 

surface with three sharp ridges, its lower striate, reaching past base of ventrals; 
dorsal spine shorter than pectoral spine, with four sharp ridges on each side and a 
median one in front, the latter sometimes broken up into teeth near the base of the 
spine; caudal truncate, very slightly emarginate or rounded; humeral process with 
lines of granules, which become stronger along the lower margin, and recurved spines 
towards its tip. 

Lateral plates regularly decreasing in height backward, each with a strong 
recurved hook, and ridges above and below which end in spines; caudal fulcra 
extending forward above and below on the caudal peduncle, but the latter largely 
naked. 

Ash-colored; head and body variously marked with black; an irregular black 
band along sides below the median hooks. A black spot at base of caudal; three 
more or less distinct black blotches on the back; one down and behind dorsal, 
one about adipose and one across caudal peduncle; dorsal and caudal, and to less 
extent the remaining fins, marked with black; lower surface variously marked. 

59. Doras cataphractus (Linnaeus). 

Silurus cataphractus Linnaeus, Syst. Nat., ed. 10, 1, 1758, 307; ed. 12, 1, 1766, 506. 
Doras cataphractus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 276 

(?).— Kner, SB. Akad. Wiss. Wien, XVII, 1855, 126 (Rio Guapore; Barra do 

Rio Negro). — Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 54. — Gunther, 

Catalogue, V, 1864, 204 (?). — Eigenmann and Eigenmann, Occasional Papers 

Cal. Acad. Sci., I, 1890, 234. — Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 393. 
Acanthodoras cataphractus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 17; " Silures 

de Suriname," 1864, 40 (Surinam). 
Cataphractus americanus Bloch and Schneider, Syst. Ichth., 1801, 107, pi. 

28.— Lacepede, Hist, Nat. Poiss., V, 1803, 124, 127 (Carolina?). 
Doras blochii Cuvier and Valenciennes, Hist. Nat, Poiss., XV, 1840, 277 (copied). 
? Doras castaneo-ventris Schomburgk, Fishes Brit, Guiana, I, 1841, 161, pi. 3 (Rio 

Pasawiri) . 
? Doras brunnescens Schomburgk, Fishes Brit. Guiana, I, 1841, 163 (Upper 

Essequibo) . 
Doras polyramma et polygramma (ex Heckel, MS.) Kner, SB. Akad. Wiss. Wien, 

XVII, 1855, 126, 127. 
Callichthys asper Gronow, Cat. Fish., ed. Gray, 1854, 157. 

One specimen, 170 mm. Kangaruma. (C. M. Cat. No. 1640.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 189 

One specimen, 84 mm. Georgetown. (C. M. Cat. No. 1641.) 

Twenty specimens, 53-112 mm. Gluck Island. (C. M. Cat. No. 1642a-c; 
I. U. Cat. No. 12032.) 

Head 3.75-4; depth equals head; width 3.16; D. 1,5; A. 10 or 11; lateral 
plates 2 or 3 + 22 to 27; eye 2.5 in snout, 9 in head, 3.5-4 in interorbital. 

Ventral surfaces of coracoid not exposed; head depressed, flat between the 
eyes, becoming slightly arched in the nuchal region, not roof-shaped, granulated 
to between the anterior nares; posterior nares just in front of the supraorbital 
ridge, scarcely protected by the low nasal bone; orbital margin, preopercle and 
opercle granular in the adult; maxillary barbel reaching to second third of humeral 
process in the adult, beyond its tip in the young; outer mental barbels scarcely 
shorter than the maxillary. Jaws equal or the upper but slightly longer; mouth 
strictly terminal, its width less than half the distance between the gill-openings. 

Pectoral spine strongly serrate on anterior and posterior margins; upper sur- 
face in young with a median series of straight teeth, in the adult with numerous 
irregularly placed teeth; lower surface rough in young, striate in adult; dorsal spine 
about two-thirds the length of the pectoral spine, its posterior surface smooth, its 
anterior surface with a series of straight spines, its sides with one or more series 
of similar spines; caudal rounded, humeral process reaching third fourth or fourth 
fifth of pectoral spine, with a series of large recurved spines in young, and smaller 
spines above them, the difference between large and small spines becoming less 
with age; lateral plates highest above origin of anal, those of opposite sides meeting 
along the median line from near the tip of the dorsal to the caudal and along the 
ventral line of the caudal peduncle; median spine of plates nearly straight, each 
plate from about the seventh with a series of teeth increasing in size toward the 
upper and lower margins; anterior plates with more numerous smaller spines. 

Black; a light median line along back of head and sometimes body; a light 
line from posterior nares following margin of skull and then along median line of 
spines. Caudal black, with hyaline bars; other fins black with hyaline blotches or 
bands; posterior margin of adipose light; lower surface and sides of head marbled. 

Oxydoras Kner. 
Oxydoras Kner, SB. Akad. Wiss. Wien, XVII, 1855, 115 (sp.); Bleeker, Nederl. 

Tijdschr. Dierk., I, 1863, 14 (niger). 
Pseudodoras Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 53 (niger). 
Rhinodoras Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 14 (Orbignyi). 

Type, Doras niger Valenciennes. 

Doradines with the barbels simple; no teeth; eye in posterior half of head, 
snout long and pointed. 



190 MEMOIRS OF THE CARNEGIE MUSEUM 

60. Oxydoras niger (Valenciennes). 
Doras niger Valenciennes, in Humboldt, Ree. Obs. ZooL, II, 1811, 184. — Cuvier 
and Valenciennes, Hist. Nat. Poiss., XV, 1840, 291 (?). — Schomburgk, Fishes 
Brit. Guiana, I, 1841, 165. — Muller and Troschel, in Schomburgk, Reisen, 

III, 1848, 629 (Rivers of Guiana).— Bleeker, Nederl. Tijdschr. Dierk.. I, 
1863, 14 (name only). 

Rhinodoras niger Gunther, Catalogue, V, 1864, 209 (Amazons). — Cope, Proc. Am. 
Philos. Soc, XVII, 1878, 678 (Nauta) .— Vaillant, Bull. Soc. Philom., (7), 

IV, 1880, 14 (Calderon). 

Oxydoras niger Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 

159 (Teffe; Gurupa; Manacapuru; Coary; Obidos); Occasional Papers Cal. 

Acad. Sci., I, 1890, 247.— Kindle, Ann. N. Y. Acad. Sci., VIII, 1894, 251 

(Para). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 393. 
Doras humboldt i 'Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 129, pi. 5 (Rio San 

Francisco, Brazil). — Agassiz, a Journey in Brazil, 1868, — . 
Corydoras edentatus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pi. 5. 
Rhinodoras prionomus Cope, Proc. Acad. Nat. Sci. Phila., 1874, 134 (Nauta); 

Proc. Am. Philos. Soc, XVII, 1878, 678 (Nauta). 
Rhinodoras teffeanus Steindachner, SB. Akad. Wiss. Wien, LXXI, 1875, 145, pi. 3 

(Teffe). 

One specimen, 178 mm. Rupununi. (C. M. Cat, No. 1622.) 

Head 3.3; depth 4.5; D. 1,6; A. 11; lateral plates 23; eye 3 in interorbital, 
4 in snout, 3 in preorbital part of head. 

Deepest in front of dorsal spine, the depth equal to the width; caudal peduncle 
depressed, its depth half the distance from anal to lower caudal rays. Head 
pointed, its width 1.4 in its length, almost equal to its depth. Opercle, top of 
head, and dorsal plate tubercular striate. Interorbital flat; fontanel narrow, in a 
wide groove continued beyond the fontanel, which does not extend beyond the 
middle of the eye. 

Lips and barbels thickly papillose, the barbels simple, free from the lips and 
not united; maxillary barbel extending a little beyond eye; distance between nares 
less than their distance from tip of snout or eye; distance between gill-openings 
equals width of mouth. Highest lateral scute less than one-fourth the length of 
the head, each scute with a very strong median hook, up to eight spines below the 
median hook and up to ten above it. 

Dorsal spine striate, with a few straight spines on its posterior surface and 
much more numerous and stronger antrorse hooks on its anterior margin. Pectoral 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 191 

spines with hooks of equal size in front and behind, the anterior antrorse, the 
posterior retrorse. Adipose fin low, gradually merging into the back in front. 
Caudal short and broad, its length equal to snout and eye. 
Slaty black, with lighter markings below; fins black. 

Leptodoras Boulenger. 

Leptodoras Boulenger, Ann. and Mag. Nat. Hist., (7), II, 1898, 477. 

Type, Oxydoras acipenserinus Giinther. 

No teeth; maxillary barbel fringed; anal 15-18; eye large. 

Boulenger creates the genus Leptodoras on account of the longer body and the 
longer anal fin, 15-17 rays. In another place (Trans. Zool. Soc, XIV, 1898,423) 
he rejects the genus Hemidoras as indistinguishable from Oxydoras. As the type 
of Hemidoras has thirteen anal rays and Hemidoras brevis has thirteen or fourteen 
it might be doubted whether Leptodoras can be separated from Hemidoras on the 
score of anal rays. Since, however, Leptodoras has no teeth it maybe kept distinct. 

The extralimital species of this genus are acipenserinus, juruensis and probably 
stubelii. I have been able to examine the types of the two former in the British 

Museum. 

Key to the Species of Leptodoras. 

a. Dorsal spine short, pungent, serrate in front. 

6. Eye 3.5 in the head; pectoral spine longer than snout and eye; reaching near middle of ventrals. 

linnelli. 
(66. Eye 5 in the head; pectoral spine longer, equal to snout and eye; reaching scarcely beyond origin 

of ventrals ". acipenserinus. 

aa. Dorsal spine prolonged, not pungent, roughened near its base; eye 6.5 in the head; pectoral 
spine reaching ventrals, head depressed juruensis.) 

61. Leptodoras linnelli sp. nov. (Plate XVII, fig. 1; Plate XVIII, fig. 1.) 

Leptodoras linnelli Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

395 (name only). 

Type, 190 mm. Tumatumari. (Carnegie Museum Catalog of Fishes 
No. 1626.) 

Cotypes, twenty-seven specimens, 64-209 mm. Tumatumari. (C. M. Cat. 
No. 1627a-e; I. U. Cat. No. 12022.) 

Cotypes, two specimens, 64 and 182 mm. Rockstone. (C. M. Cat. No. 1628; 
I. U. Cat. No. 12024.) 

Cotypes, six specimens, 75-103 mm. Crab Falls. (C. M. Cat. No. 1629a; 
I. U. Cat. No. 12023.) 



192 MEMOIRS OF THE CARNEGIE MUSEUM 

Cotype, one specimen, 174 mm. Georgetown market ? (C. M. Cat. No. 
1630.) 

Head 3.5; depth 6; D. 1,6; A. 12-14; lateral plates 38-39; eye 3.5-4 in head, 
1.75-1.8 in snout; interorbital 2 in eye. 

Slender; depth equal to width; caudal peduncle broad, depressed, its depth 
equal to half its width, less than the distance of the anal from the caudal ; fontanel 
continued as a groove to the tip of the occipital process. A small foramen on 
either side of the occipital process; no teeth; mouth nearly equal to the distance 
between the gill-openings. Maxillary barbel reaching gill-opening in the young, 
shorter in the adult. 

Lateral plates well-developed along the entire sides, each with a central hook 
and a series of marginal spines, those above the median hook close-set; median 
hook strongest on the plates, just behind the vertical from the anal; humeral 
process short, its upper margin greatly arched. 

Dorsal and pectoral spines of about equal length, little shorter than the head, 
the pectoral spine reaching to the middle of the ventrals or farther in the adult, 
not much beyond the base in the young; pectoral spine serrate on both edges, the 
teeth much stronger on the inner surface; dorsal spine with much feebler serrations; 
adipose free behind, its base nearly or quite equal to the base of the dorsal exclusive 
of the spine. A large pectoral pore. 

White beneath, uniform dark above; a pair of parallel bands on the caudal, 

the middle rays light. 

Hemidoras Bleeker. 

Doras Lacepede, Hist. Nat. Poiss., V, 1803, 116 (carinatus and costatus).— 

Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 13 (carinatus), not Doras Cuvier 

and Valenciennes. 
Oxydoras Kner, SB. Akad. Wiss. Wien, XXVII, 1855, 142 (sp.). 
Hemidoras Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 53 (stenopeltis) . 
Hassar Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 158 (orestes). 

Type, Doras stenopeltis Kner. 

Barbels fringed; eye large. One or both jaws with teeth; numerous pectoral 
pores. 

Key to the Guiana Species of Hemidoras. 

a. No foramen on either side of juncture between occipital process and dorsal plate. (Hemidoras.) 

b. Lateral plates of the anterior part of the body well-developed; teeth in the lower jaw small, in 

two patches. 

c. Groove of the fontanel not extending backward; maxillary barbel not reaching gill-opening. 

Eye 2.75 in head (1 in young); teeth very feeble, mouth half as wide as distance 

between gill-openings microstomus. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 193 

cc. Maxillary barbel extending to base of pectoral ; eye 4.5 in the head in the adult (3 in the young), 
2.75 in the snout (1.5 in young); teeth well-developed in both jaws; snout pointed; 

mouth 1-1.5 in distance between gill-openings carinatus. 

bb. Lateral plates of anterior part of body rudimentary or very small, increasing in size backward. 
d. Teeth of the lower jaw minute, in two separate patches; differing from carinatus largely 

in the rudimentary anterior plates micropoeus. 

dd. Teeth of the lower jaw large, brown-tipped, in a single median patch; maxillary barbel ex- 
tending beyond origin of pectorals; snout bluntly decurved; pectorals extending to 
ventrals; base of dorsal dark; a light band along the lateral hooks, bordered above 

and below by darker, which is most intense on base of caudal leporhinus. 

ao. A large foramen on either side of the juncture between dorsal plate and occipital process; dorsal with 
a conspicuous black spot. (Hassar.) 
c. Maxillary barbel extending to base of pectoral; orbit oval; snout long, conical; pectoral spine reach- 
ing ventrals; dorsal spine with hooks on the basal half of the anterior margin; humeral 

process elongate, its upper margin not greatly arched notospilus. 

(ee. Maxillary barbel to below posterior part of the eye; orbit ovate with a narrowing forward exten- 
sion; snout slender; origin of orbit behind the middle of the head; pectoral spine not 
reaching ventrals; dorsal spine with hooks along the basal two-thirds or three-fourths of its 
anterior margin; humeral process spatulate, its dorsal margin much curved. 

/. Scapula covered with skin; dorsal spot not extending to tip of the membranes orestes. 

//. Scapula granular; black spot extending to upper margin of dorsal membranes wilderi.) 



62. Hemidoras microstomus sp. nov. (Plate XVIII, fig. 2.) 

Hemidoras microstomus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 394 (name only). 

Type, 52 mm. Rockstone. (Carnegie Museum Catalogue of Fishes No. 1650.) 

Cotypes, twelve specimens, 35-51 mm. Crab Falls. (C. M. Cat. No. 1651 
a-b; I. U. Cat. No. 12040.) 

Cotype, one specimen, 52 mm. Rockstone. (I. U. Cat. No. 12039.) 

Head 3.75-4.2; depth 4.33-5.5; D. 1,6; A. 10-12; lateral plates 26-32; eye 
2.5-2.66 in the head, 1-1.33 in the snout; interorbital 1-1.66 in eye. 

Profile from dorsal to above eye straight, then descending rapidly; the snout 
very blunt, rounded; lower jaw much shorter, included; fontanel elliptical, little 
longer than eye, not continued as a groove; top of head convex. Width of mouth 
equal to half the distance between gill-openings. Teeth very feeble, if present. 
Maxillary barbels reaching gill-openings, or a little shorter; distance of dorsal 
spine from tip of snout 2.75-3 in the length. 

Dorsal spine as long as the head or a little longer, with serrse on the basal half 
of the anterior margin and entire length of posterior margin. Pectoral spine a 
little longer or shorter than the dorsal spine, reaching the ventrals; base of adipose 



194 MEMOIRS OF THE CARNEGIE MUSEUM 

less than diameter of eye. Lateral shields small, of uniform height, height 2.5-3.3 
in eye, hooks highest above tip of anal fin. Humeral process four times as long 
as broad, spine-like. 

Sides and back covered with minute black dots, thickest at base of dorsal 
and caudal fins, white underneath. 

63. Hemidoras carinatus (Linnseus). 

Silurus carinatus Linnaeus, Syst. Nat., ed. 12,1,1766,504. — Bloch and Schnei- 
der, Syst. Ichth., 1801, 108. 

Doras carinatus Lacepede, Hist. Nat. Poiss., V, 1803, 116 (Surinam). — Cuvier 
and Valenciennes, Hist. Nat. Poiss., XV, 1840, 288, pi. 442 (Cayenne). — 
M tiller and Troschel, in Schomburgk, Reisen, III, 1848, 629 (Essequibo). — 
Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 54; Nederl. Tijdschr. Dierk., I, 
1863, 13 (name only); " Silures de Suriname," 1864, 31 (Surinam). 

Doras (Oxydoras) carinatus Kner, SB. Akad. Wiss. Wien, XVII, 1855, 144 
(Surinam). 

Oxydoras carinatus Gunther, Catalogue, V, 1864, 206 (Surinam ; Essequibo River) . — 
Vaillant, Bull. Soc. Philom. (7), IV, 1880, 154 (Calderon). 

Hemidoras carinatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 
1888, 158; Occasional Papers Cal. Acad. Sci., 1, 1890, 258. — Eigenmann, Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 394. 

Doras oxyrhynchus Valenciennes, in Humboldt, Rec. Obs. Zool., II, 1833, 184. 
One hundred and thirty-three specimens, 44-320 mm. Tumatumari. (C. M. 

Cat. No. 1631«-2; I. U. Cat. No. 12025.) 

One specimen, 95 mm. Bartica. (C. M. Cat. No. 1632.) 

Ninety-two specimens, 48-267 mm. Rockstone. (C. M. Cat. No. 1633a-t; 

I. U. Cat, No. 12026.) 

Three specimens, 45, 113, and 247 mm. Georgetown market. (C. M. Cat. 

No. 1634a; I. U. Cat. No. 12027.) 

One hundred and sixteen specimens, 39-140 mm. Crab Falls. (C. M. Cat. 

No. 1635a-i; I. U. Cat. No. 12028.) 

Head 3.16-3.33; depth 4.25-4.5; D. 1,6; A. 11-14; lateral plates 33; eye 3- 

4.5 in the head, 1.5-2.75 in the snout, the snout proportionately longer in the 

old individuals; interorbital 1.3-1.5 in the eye. 

Heavy below the dorsal, the width 1.25 in the depth; caudal peduncle as 

wide as deep, its depth less than distance of anal from the lower caudal rays; 

occipital area roof-shaped, with a median groove which is not continued to the 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 195 

fontanel; profile abruptly descending in front of the eye, the snout sharp; a pair 
of patches of small teeth in each jaw; those of the upper jaw sometimes wanting; 
mouth narrow, 1-1.5 in the distance between the gill-openings. Maxillary barbel 
reaching to the gill-openings. 

Lateral plates nearly equally well-developed along the entire length; humeral 
process truncate, its upper and lower margins nearly parallel, its depth one-third 
of its length. 

Distance between snout and dorsal 2.5 in the length, dorsal spine as long as 
snout and eye or shorter; pectoral spine longer than dorsal spine, reaching the 
ventrals; adipose fin low, its base equal to the base of the dorsal without the spine. 
Axillary pores numerous. 

White below, ashy above, no definite markings. In the specimen from Bartica 
the dorsal spine is margined with dark. 

64. Hemidoras micropceus sp. nov. 

Hemidoras micropceus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 394 (name only). 

Type, 365 mm. Wismar. (Carnegie Museum Catalog of Fishes No. 1636.) 

Cotype, 217 mm. Wismar. 

Cotypes, two specimens, 250-270 mm. Lama Stop-Off. (C. M. Cat. No. 
1637; I. U. Cat. No. 12029.) 

These specimens differ from carinatus in having the plates from above the 
ventrals forward rudimentary. 

65. Hemidoras leporhinus sp. nov. (Plate XIX, fig. 1.) 

Hemidoras leporhinus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 394 (name only). 

Type, 56 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 
1624.) 

Cotypes, three specimens, 53-59 mm. Crab Falls. (C. M. Cat. No. 1625; I. 
U. Cat. No. 12021.) 

Readily distinguished by its peculiar leporine snout, and by its mouth, lower 
teeth, and coloration. 

Head nearly 4; depth 5; D. 6; A. 12; lateral plates 33 to 35; eye 2.4 in the head, 
equal to the snout; interorbital 1.6 in the eye. 

Depth equal to the width in front of the pectoral; caudal peduncle slender, its 
depth equal to the distance of the anal from the caudal fulcra; profile curved, 



196 MEMOIRS OF THE CARNEGIE MUSEUM 

sharply so in front of the eye; snout pointed; fontanel continued as a groove to the 
tip of the dorsal plate; a small foramen on either side of the juncture between the 
dorsal plate and occipital process; mouth 2 in the distance between the gill-open- 
ings; five to seven teeth in each ramus of the lower jaw, grouped in front so as to 
form one continuous patch; maxillary barbel reaching at least to base of pectoral; 
humeral process more than three times as long as wide, rounded behind. 

Lateral plates deepest above end of anal, their depth four-tenths of the length 
of the eye. 

Distance of origin of dorsal from tip of snout 2.7 in the length. 

Dorsal and pectoral spines about equal in length and equal to the length of the 
head. 

Belly white; sides of head and body thickly dotted, darkest on dorsal surface of 
caudal peduncle; a light stripe along the lateral plates and middle caudal rays; 
bases of the caudal fulcra and a band above and below the central light band black; 
tip of upper lobe dusky; a dark area on base of dorsal, highest on the spine. 

66. Hemidoras notospilus sp. nov. (Plate XIX, fig. 2.) 

Hemidoras notospilus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 394 (name only). 

Type unique, 70 mm. Crab Falls. (Carnegie Museum Catalog of Fishes 
No. 1623.) 

Head 3.33; depth 5; D. 1,6; A. 12; lateral plates 33; eye 3 in head, 1.5 in snout; 
interorbital a little more than half the eye. 

Profile from dorsal to above front of eye nearly straight, descending rapidly in 
front of eye; snout pointed, lower jaw much the shorter; fontanel continued as a 
groove to the occipital, not to the tip of the process or the dorsal plate; dorsal plate 
bat-shaped, a large foramen on either side of it in front; interorbital and snout 
narrow; depth of head greater than its width, 1.5 in its length. Eye oval, 1.75 
times as long as high. 

Maxillary barbel reaching pectoral, having numerous small barblets; mental 
barbels papillose. Distance of dorsal spine from tip of snout 2.5 in the length. 

Dorsal spine a little longer than snout and half the eye. Pectoral spine a 
little longer than the dorsal spine, reaching the ventrals. Base of adipose less than 
the length of the eye. 

Lateral shields highest above end of anal, their height 1.33 of the length of 
the eye. Humeral process more than three times as long as broad. 

Belly white, sides with an increasing amount of pigment toward the back; 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 197 

base of dorsal and sides of the spine dotted, rest of fin hyaline, except a conspicuous 
black spot near the tip of the first three dorsal rays. 

Subfamily Auchenipterin^e. 
Centromochlus Kner. 

Centromochlus Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 430 (megalops = 

heckelii) . 
Glanidium (ex Reinhardt, MS.) Lutken, Dan. Vidensk.-Selsk. Skr., XII, 1874, 31 

(albescens). 

Type, Centromochlus megalops Kner. 

Mental barbels in two pairs; adipose fin shorter than the anal; anal short, 
7-11; mouth terminal; jaws equal; caudal forked; V. 6. 

67. Centromochlus aulopygius Kner. (Plate XX, fig. 1.) 

Centromochlus aulopygius Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 432, pi. 8, 
fig. 25 (Rio Guapore). — Gunther, Catalogue, V, 1864, 198 (Essequibo). — 
Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 157 
(Cudajas); Occasional Papers Cal. Acad. Sci., I, 1890, 270. — Pellegrin, 
Bull. Mus. d'Hist. Nat., V, 1899, 158 (Apure) —Eigenmann, Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 395. 

One specimen, 65 mm. Creek below Potaro Landing. (C. M. Cat. No. 
1727.) 

One specimen, 65 mm. Wismar. (I. U. Cat. No. 12643.) 
Head 3.75-4.25; depth 4-5; D. 1,4 or 1,5; A. 9 or 10; eye 5 in snout, 3 in 
head, 2 in interorbital. 

Head blunt, bullet-shaped; tail compressed; top of head finely granular; an 
ovate fontanel, its posterior margin over the last third of the eye; jaws subequal; 
teeth conical, fixed, in narrow bands; lower margin of gill-opening on a level with 
the upper margin of the pectoral spine; maxillary barbel reaching slightly beyond 
the middle of the pectoral spine; mental barbels reaching beyond base of post- 
mentals, the post-mentals not to base of pectoral. 

Dorsal spine a little shorter than the pectoral spine, as long as the head; 
anterior margin of dorsal with large antrorse teeth, the posterior margin smooth; 
pectoral spine serrate on both margins, the teeth of the posterior margin larger. 
Ventrals not reaching to anal; anal rays crowded, especially in the Wismar speci- 
men; adipose fin shorter than the dorsal. 

Chocolate brown above, shading to white on the belly; sides of body and 
caudal with numerous horizontally-oval light spots; lower fins light. 



198 MEMOIRS OF THE CARNEGIE MUSEUM 

Trachycorystes Bleeker. 

Trachycorystes Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (typus = trachy- 
corystes) . 

Parauchenipterus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (galeatus). 
Type, Trachycorystes typus Bleeker. 
Mental barbels in two pairs; adipose fin shorter than the anal fin; anal 19-41; 

caudal obliquely truncate or slightly emarginate; outer margin of pectoral spine 

serrate. 

Key to the Species of Trachycorystes. 
a. Caudal oblique. 

6. Dorsal spine longer than the pectoral spine, which is 1.5 in the head; head covered with smooth 

skin glaber. 

66. Pectoral spine longer than dorsal spine, about as long as head; head granular, or covered with 

thin skin in the young; A. 22-28 galeatus. 

aa. Caudal emarginate; A. 19 or 20; dorsal spine serrate on its anterior edge; pectoral spine as long as 
the head obscurus. 

68. Trachycorystes glaber (Steindachner). 

Auchenipterus glaber Steindachner, " Siisswasserfische Siidostlichen Brasilien," iii, 

1876, 97, footnote (Demerara). 
Trachycorystes glaber Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 154 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 272, 275 — 

Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 395. 

No specimens of this species were obtained. It is known from the types in 
the Vienna Museum. 

D. 1,5; A. 23; dorsal spine smooth on outer, weakly serrate on inner margin, 
longer than pectoral spine, 1.25 in the head; pectoral spine 1.5 in the head; caudal 
obliquely rounded. 

69. Trachycorystes galeatus (Linnseus). 

Silurus galeatus Linnaeus, Syst. Nat., ed. 12, I, 1766, 503 (based on Seba, Locupl. 

Rer. Nat. Thes. Ace. Descr., Ill, 1748, pi. 29, fig. 7).— Gmelin, Syst. Nat., 

I, iii, 1788, 1357.— Bloch, Ausl. Fische, VIII, 1794, 39, pi. 369, fig. 1- 

Bloch and Schneider, Syst. Ichth., 1801, 384. 
Pimelodus galeatus Lacepede, Hist. Nat. Poiss., V, 1803, 97, 114 (South America). 
Auchenipterus galeatus Gunther, Catalogue, V, 1864, 196 (Guiana). — Peters, 

MB. Akad. Wiss. Berlin, 1877, 470 (Calabozo). 
Parauchenipterus galeatus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (name 

only); " Silures de Suriname," 1864, 45 (Surinam). 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 199 

Trachycorystes galeatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 155 (Pernambuco; San Goncallo; Rio San Francisco, below the falls; 

Tabatinga; Teffe; Rio Puty); Occasional Papers Cal. Acad. Sci., I, 1890, 

279. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 396. 
Auchenipterus maculosus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

216 (Cayenne). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 

639 (Essequibo).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 425 (Mara- 

bitanos). — Gunther, Catalogue, V, 1864, 196 (Surinam; Essequibo). — Vail- 

lant, Bull. Soc. Philom., (7), IV, 1880, 154 (Calderon). 
Auchenipterus immaculahts Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 

1840, 218 (Cayenne). 
Auchenipterus punctatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

219 (Brazil?). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 

629 (Essequibo).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 425 (Rio 

Branco). 
Auchenipterus lacustris Lutken, Dan. Vidensk.-Selsk. Skr., XII, 1875, 148, with 

fig. (Rio das Velhas). 
Auchenipterus robustus Gunther, Catalogue, V, 1864, 197 (Demerara). 
Trachycorystes robustus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 

I, 1888, 156 (name only). 

One specimen, 110 mm. Mud-flats, Demerara River, below Wismar. (C. M. 
Cat. No. 1717a.) 

One specimen, 132 mm. Barima River. (,C. M. Cat. No. 1718a.) 

Five specimens, 116-160 mm. Aruka River. (C. M. Cat. No. 1719a; I. U. 
Cat. No. 12096a-6.) 

Eleven specimens, 99-195 mm. Lama Stop-Off. (C. M. Cat, No. 1720a-6; 
I. U. Cat. No. 12093.) 

Four specimens, 130-228 mm. Georgetown trenches. (C. M. Cat. No. 1721a; 
I. U. Cat. No. 12094.) 

One specimen, 167 mm. Maduni Creek. (C. M. Cat. No. 2229.) 

Four specimens, 91-140 mm. Chipoo Creek. (C. M. Cat. No. 1722a-6; 
I. U. Cat. No. 12095.) 

Head 4-4.5; depth 3.5-4; D. 1,6; A. 22-27, most frequently 24; V. 6; P. 1,6. 
Eye 1.5-2 in snout, 5.5-6 in head, 3.5-4 in interorbital. 

Head heavy, its width equal to its length, depressed, profile but little concave 
at the nape, rounded forward, the lower jaw entering the profile; upper surface 
of head finely granular in the old, covered with thin smooth skin in the young; 



200 MEMOIRS OF THE CARNEGIE MUSEUM 

fontanel surrounded by bone; maxillary barbel reaching to or beyond tip of the 
humeral process, mental barbel 2.5-3 times as long as the eye. 

Dorsal spine equal to head without the snout or a little longer but not equal 
to the length of the head, rough in front, with recurved hooks for over half its 
length from the tip on the posterior margin; pectoral spine as long as the head, 
with antrorse teeth in front and larger retrorse teeth behind; caudal obliquely 
rounded. 

Color variable, much lighter in those inhabiting muddy water, with a light 
band across the head behind the eye, the dorsal plate also light, sides strigate; 
much darker to black in those inhabiting clear waters, the sides strigate. 

The specimens from Chipoo Creek, a tributary of the Ireng, differ from those 
near the coast in having the maxillary barbels a little shorter, reaching to or not 
quite to the tip of the humeral process, the mental barbels 1.5-1.75 times as long 
as the eye. 

70. Trachycorystes obscurus (Giinther). (Plate XVII, fig. 2.) 

Auchenipterus obscurus Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 442 

(Essequibo); Catalogue, V, 1864, 195. 
Trachycorystes obscurus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 

I, 1888, 154; Occasional Papers Cal. Acad. Sci., I, 1890, 275. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 396. 

I have examined the types in the British Museum and two specimens in the 
Berlin Museum, all collected by Ehrhardt. 

No specimens of this species were secured by me. 

The species is readily distinguished by its emarginate caudal. 

D. 1,5; A. 19-20; maxillary and post-mental barbel extending to, or somewhat 
beyond, the tip of the humeral process; mental barbel 2 or 3 times as long as the 
eye; dorsal serrate along its anterior edge; pectoral serrate along both edges; dorsal 
spine shorter than the pectoral spine, which equals the head in length; caudal 
emarginate, the upper lobe scarcely longer than the lower. Uniform brownish black. 

Pseudauchenipterus Bleeker. 

Felichthys Swainson, Class. Fishes, Amph., and Rept., II, 1839, 305 (sp). — Swain, 

Proc. Acad. Nat. Sci. Phila., 1882, 281 (nodosus). 
Pseudauchenipterus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (nodosus). 

Type, Silurus nodosus Bloch. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 201 

71. Pseudauchenipterus nodosus (Bloch). (Plate XX, fig. 2.) 

Silurus nodosus Bloch, Ausl. Fische, VIII, 1794, 35, pi. 368, fig. 1 (Tranque- 

bar?). — Bloch and Schneider, Syst. Ichth., 1801, 383. 
Arius nodosus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 70 

(copied). 
Auchenipterus nodosus MtJLLERand Troschel, Horse Ichth., Ill, 1849, 11. — Kner, 

SB. Akad. Wiss. Wien, XXVI, 1857, 424 (Surinam).— Gunther, Catalogue, 

V, 1864, 194 (British, Dutch, and French Guiana). 
Pseudauchenipterus nodosus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (name 

only); " Silures de Suriname," 1864, 43, pi. 11, fig. 1, pi. 13, fig. 6 (Surinam). 

—Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 396. 
Felichthys nodosus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 

154 (Para; Bahia); Occasional Papers Cal. Acad. Sci., I, 1890, 291. 
Auchenipterus furcatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

211 (Guiana). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 629 

(Essequibo) . 
Pseudauchenipterus guppyi Regan, Proc. Zool. Soc. London, 1906, 387 (Trinidad). 
Par auchenipterus paseadw Regan, Proc. Zool. Soc. London, 1906, pi. 23. 

Twenty specimens, 210-290 mm. Georgetown market. (C. M. Cat. No. 
1723a-e; I. U. Cat. No. 12097.) 

Three specimens, 137-145 mm. Mahaica. (C. M. Cat. No. 1724a; I. U. 
Cat, No. 12098.) 

Two specimens, 212 and 227 mm. Mud-flats of Demerara River, near Wismar. 
(C. M. Cat. No. 1725a; I. IT. Cat. No. 12099.) 

Head 4.2; depth 45-4.75, D. 1,6; A. 21 or 22; V. 8; P. 1,7. Eye about 1 
in snout, 4.25 in head, 2.5 in interorbital. 

Subtriangular in front, the head blunt, the tail compressed; maxillary barbel 
reaching posterior third of pectoral spine, mental barbel beyond base of pectoral, 
post-mental to middle of pectoral spine; head nearly as broad as long; frontal 
bones pitted, not much swollen; lower jaw included. 

Dorsal spine 3-3.6 in the length, feebly serrate behind; pectoral spine 3.5-3.75 
in the length, its outer margin striate, its inner finely serrate. Caudal forked; 
anal slightly emarginate. 

Back and sides dark blue; an undulating white streak follows the lateral line, 
dividing with it on the caudal; area above anal lighter than the rest of the sides; 
upper and lower margin of caudal light, the hinder margin black; tips of remaining 
fins light. 



202 MEMOIRS OF THE CARNEGIE MUSEUM 

Auchenipterus Cuvier and Valenciennes. 
Auchenipterus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 207 

{nuchalis) . 
Evanemus Muller and Troschel, Horse Ichth., Ill, 1849, 11 (colymbetes) . 

Type, Hypophthalmus nuchalis Spix. 

Mental barbels arranged in a line near the symphysis; a short adipose fin; 
anal long; ventrals with 12 to 15 rays; pectorals 1,11. 

Key to the Species of Auchenipterus. 

a. Mandibular barbels extending to the tip of the pectoral demerarae. 

aa. Mandibular barbels extending to the lower angle of the gill-opening brevior. 

72. Auchenipterus demerarae sp. nov. (Plate XXI, fig. 1.) 

Type, 115 mm. Wismar. (Carnegie Museum Catalog of Fishes No. 1714.) 

Cotype, 115 mm. Malali. (C. M. Cat. No. 1713.) 

Cotypes, two specimens, 101 and 118 mm. Wismar and mud-flats just below 
Wismar. (I. U. Cat. No. 12091.) 

Similar to Auchenipterus nuchalis (Spix), but with a lateral band. 

Head 5.25; depth 4.75; D. 1,6; A. 41 to 44; V. 12; P. 1,11; eye 3 in head, 
1.5 in interorbital, 1 in snout; depth of caudal peduncle 2 in the head. 

Head short, blunt, depressed; body much compressed; occipital process as 
long as wide, fontanel as long as the pupil, its anterior edge but slightly in advance 
of the posterior margin of the eye; lower jaw slightly included, the teeth in very 
narrow bands ; gill-membranes free to behind the lower margin of the pupil ; maxil- 
lary barbel extending to the tip of the pectoral, mandibular barbels to the middle 
of the pectorals; distance from tip of snout to dorsal 4.33 in the length, the spine 
equal to snout and eye, with a few recurved notches on the posterior margin near 
the tip; pectoral spine but little shorter than the head, smooth in front, with 
recurved teeth along its entire posterior margin; pectorals not reaching ventrals, 
ventrals to about the sixth anal ray ; highest anal ray equals snout and eye; middle 
caudal rays about half as long as the outer. 

Sides everywhere peppered; a dark median band from the gill-opening to the 
caudal; dorsal and caudal dusky, the tip of the upper caudal lobe sometimes quite 
dark; lower fins hyaline. 

73. Auchenipterus brevior sp. nov. 

Type, 71 mm. Tumatumari. (Carnegie Museum Catalogue of Fishes No. 
1715a.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 203 

Cotypes, twenty specimens, 50-73 mm. Tumatumari. (C. M. Cat. No. 1716 
a-d; I. U. Cat. No. 12108.) 

These specimens differ from demerarce notably in one observed particular : the 
mandibular barbels extend to about the lower angle of the gill-opening, not to the 
pectoral. 

The maxillary barbels are as long as in demerarce; depth 5.33. 

Subfamily Ageneiosin^e. 
Tympanopleura 19 gen. nov. 

Type, Tympanopleura piper ata sp. nov. 

Maxillary barbels only, short. Air-bladder projecting into the abdominal 
cavity, naked laterally, the skin over it forming a large pseudo-tympanum; snout 
short, about equal to the eye; profile very concave; first dorsal and first pectoral 
rays pungent; origin of anal equidistant from rictus and middle caudal rays. 

74. Tympanopleura piperata sp. nov. (Plate XX, fig. 3.) 

Type, a male, 64 mm. Crab Falls. (Carnegie Museum Catalog of Fishes 
No. 1708.) 

Cotypes, two males and five females, 57 -61 mm. Crab Falls. (C. M. Cat. No. 
1709a; I. U. Cat. No. 12090.) 

This is evidently a young fish. To what extent the large, protruding air- 
bladder and the large pseudo-tympanum are characters of immaturity I am unable 
to say. The short snout very probably is due to the age of the specimen. 

Head 4.5; depth 4.75; D. 1,5 or 6; A. 31; V. 7; P. 1,9; Br. 7; eye 1 in snout, 
2.8 in head, 1 in space between the eyes below. 

Profile much concave; fontanel open in front, continued as a groove to above 
the posterior margin of the pupil; snout rounded, the gape short; maxillary barbel 
in the male with an osseous base extending to below the anterior margin of the eye, 
the fleshy tip a little farther; in the female, minute, fleshy, reaching the rictus; 
gill-opening extending to below the posterior margin of the eye; dorsal spine with 
minute teeth on its front margin, its posterior margin smooth in the male, with 
recurved teeth along its entire length in the female; pectoral spine smooth in front, 
with recurved teeth along its entire margin behind; a large pectoral pore. Distance 
of dorsal from snout 3.66 in the length; origin of anal equidistant from rictus 
and caudal; ventrals reaching past origin of anal; pectorals not to ventrals. 

19 Tvniravov, tympanum, Tr\evpi, side. 



204 MEMOIRS OF THE CARNEGIE MUSEUM 

Sides everywhere lightly peppered with ehromatophores ; an hour-glass-shaped 
dark bar across the base of the caudal. 

Ageneiosus Lacepede. 

Ageneiosus Lacepede, Hist. Nat. Poiss., V, 1805, 132 (armatus); IX, 167. 
Pseudageneiosus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 108 (davalla). 
Ageniosus Gunther, Catalogue, V, 1864, 191 (sp.). 

Type, Ageneiosus armatus Lacepede. 

Maxillary barbels only; air-bladder minute, concealed under the peritoneum 

and largely covered with bone; no pseudo-tympanum. Snout much longer than 

the eye. 

Key to the Guiana Species of Ageneiosus. 

a. Caudal deeply forked. 

6. A. 45; back with obscure marblings; maxillary band of teeth comma-shaped, the teeth large; 
dorsal and pectoral spines slender, pungent; origin of anal a little nearer base of middle 
caudal rays than the rictus; pectorals not reaching ventrals. Head 4: P. 1,14; Br. 9. 

guianensis. 

aa. Caudal emarginate; dorsal and pectoral rays smooth on posterior margin, the pectoral ray not 

pungent. 

c. Dorsal spine strong, sinuate, rough or spinous in front; profile steep, concave, origin of anal 

equidistant from base of middle caudal rays and anterior margin of eye; pectoral falcate, 

the first ray reaching beyond origin of ventrals; head 3.66; P. 1,14; Br. 9; A. 34, dark 

above, lighter below brevifilis. 

cc. First dorsal ray not spinous; profile nearly straight and horizontal; origin of anal a little nearer 
origin of pectoral than to base of middle caudal rays; pectoral rounded, not reaching ven- 
trals; head 3.33; P. 16; Br. 10; A. 29. Conspicuously marked with light and dark. 

marmoratus. 

75. Ageneiosus guianensis sp. nov. (Plate XXI, fig. 2.) 

Type unique, a female, 175 mm. Wismar. (Carnegie Museum Catalog of 
Fishes No. 1712a.) 

Head 4; depth 5.5; D. 1,6; A. 45; V. 8; P. 1,14; Br. 9; eye 3 in snout, 6 
in head, 3.5 in space between the eyes below. 

Profile concave, not very steep, snout much depressed; width of head 1.4 in 
its length; length of snout less than interocular width by about an orbital diameter; 
fontanel reaching above middle of eyes, the groove considerably farther; cleft of 
mouth 3 in the length of the head; half the maxillary barbel osseous, its tip reaching 
rictus; premaxillary band of teeth comma-shaped, widest in front, its width half 
the length of the eye, the teeth comparatively large. Gill-openings extending 
to below the posterior margin of the eye, the space between them about equal to 
the diameter of the eye. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 205 

Distance from snout to dorsal 3.6 in the length; the spine slender, with minute 
wide-set teeth on the anterior margin, more numerous minute teeth on the posterior 
margin; pectoral spine slender, pungent, slightly rough in front, with small curved 
teeth along its entire inner margin; caudal deeply forked, the middle rays not half 
as long as the outer rays, which are 4.5 in the length; origin of the anal a little 
nearer to the base of the middle caudal rays than to the rictus; ventrals reaching 
beyond origin of anal; pectorals four-fifths the distance to the ventrals. 

Dark chocolate above, shading to the anal; ventral surface light; back ob- 
scurely marbled; dorsal, base and tips of caudal, upper surface of pectoral and 
ventral, except their last rays, dark. 

This species is near dentatus Kner and ucayalensis Castelnau, but differs in 
the width of the head, the length of the snout, the mouth, color, etc. 

76. Ageneiosus brevifilis Cuvier and Valenciennes. 

Ageneiosus inermis (not Silurus inermis Linnaeus or Bloch) Cuvier and 
Valenciennes, Hist. Nat. Poiss., XV, 1840, 240, pi. 440 (Surinam).— 
Castelnau, Anim. Am. Sud, Poiss., 1855, 48 (Amazon). 

Ageneiosus brevifilis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 242 
(Cayenne).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 438 (Rio Cujaba).- 
Gunther, Catalogue, V, 1864, 192 (River Capin, Para); Proc. Zool. Soc. 
'London, 1868, 229 (Xeberos).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 
676 (Peruvian Amazon). — Eigenmann and Eigenmann, Proc. Cal. Acad. 
Sci., (2), I, 1888, 150 (name only); .Occasional Papers Cal. Acad. Sci., I, 
1890, 309. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
397. 

Pseudageneiosus brevifilis Bleeker, " Silures de Suriname," 1864, 83, pi. 16, fig. 1 
(Surinam) . 

Hypophthalmus dawalla Schomburgk, Fishes Brit. Guiana, I, 1841, 191, pi. 9 
(Guiana). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 643. 

Ageneiosus dawalla Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 
1888, 150 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 309. 

Ageniosus sebce Gunther, Catalogue, V, 1864, 192 (copied). 

One specimen, a male, 445 mm. Lama Stop-Off. (C. M. Cat. No. 1711a.) 
Head 3.66; depth 5; D. 1,6; A. 34; V. 8; P. 1,14; Br. 9; eye 3.5 in snout, 

6.5 in head, 5.5 in space between the eyes below. 

Profile steep, concave; head depressed, broad; fontanel reaching eye, the 

groove beyond the posterior margin of the eye; maxillary barbel osseous to near its 



206 MEMOIRS OF THE CARNEGIE MUSEUM 

tip, tuberculate above, reaching the eye; premaxillary band of teeth .66 of the 
length of the eye, the teeth minute; gill-openings reaching to below the eye, the 
space between them equal to the eye. 

Distance from snout to dorsal 3.66 in the length; the spine an orbital diameter 
shorter than the head, with short sharp teeth along its concave anterior margin, 
the posterior margin smooth; caudal emarginate; origin of anal equidistant from 
base of middle caudal rays and the anterior margin of the eye, its first rays thick^ 
ened, osseous; ventrals emarginate, reaching to the third anal ray; pectorals sub- 
falcate, the first ray not pungent, smooth on both margins, reaching the first or 
fifth ventral ray. 

Steel-blue above, lighter below; dorsal spotted; upper surface of pectoral and 
anterior ventral rays steel-blue, the membranes white with dark spots; caudal 
margined with light ; a submarginal dark band shading into the color of the caudal 
peduncle. 

Bleeker's figure was based on his smaller specimen, and the markings are still 
visible on the fins. The barbel is however too long, not reaching the eye. 

77. Ageneiosus marmoratus sp. nov. (Plate XXII, fig. 1.) 

Type unique, a female, 175 mm. Creek below Potaro Landing. (Carnegie 
Museum Catalog of Fishes No. 1710.) 

Readily distinguished by its conspicuous markings and short anal. 

Head 3.33; depth 5; D. 1,6; A. 29; V. 8; P. 16; Br. 10; eye 3.5 in snout, 6.3 
in the head, 4 in the interocular space ventrad. 

Head wedge-shaped, much depressed, the profile nearly straight and but little 
ascending; snout parabolic, the gape of the mouth very long, about three times as 
long as the eye; fontanel extending to the anterior margin of the eye, its groove 
to the posterior margin; premaxillary band of teeth half as wide as the eye, of 
nearly uniform width to near the posterior end of the band; maxillary barbel not 
reaching the rictus; gill-membranes free to below middle of the eye, the distance 
between the clefts not equal to the eye; distance from snout to dorsal spine 3 in 
the length; caudal emarginate; origin of anal but very little nearer base of pectoral 
spine than to base of middle caudal rays; first dorsal and pectoral rays not pungent, 
smooth on both margins. 

. Sides light, with spots and streaks of slaty; upper part of sides with five large 
dusky spots margined with darker, not meeting on the middle line; dorsal black, 
with a light band at base and another a little higher up; bases of caudal and anal 
colored like the sides, then a broad black band, then narrowly margined with 
hyaline; pectorals and ventrals black above, with a light band at the base. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 207 

Family IV. HELOGENEID.E Fam. nov. 

< Siluridce anomalopterce Gunther, Catalogue, V, 1864, 3, part. 

Dorsal small, behind the middle of the body; anal long, its origin near the 
beginning of the fifth ninth of the body; dorsal and pectoral without spines; adi- 
pose fin minute; caudal forked; gill-membranes free from the isthmus; teeth few; 
six barbels; nares without barbels; eyes very small, directed upward and outward; 
air-bladder transversely uniform, not covered by bone. 

So far known from one genus. 

Helogenes Gunther. 

Helogenes Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 (marmoratus). 

Type, Helogenes marmoratus Gunther. 

This genus agrees with Hypophthalmus in its long anal and the backward 
position of the dorsal, but differs from it in so many other essential characters that 
it is but remotely related to that genus. 

Upper jaw heavy, the snout rounded, lower jaw included; vomerine teeth in 
two separate patches; upper jaw with two series of teeth, the inner obscure; lower 
jaw with a narrow band of teeth, some of the outer ones distinctly larger than the 
rest; head bullet-shaped, the eyes on side of head, superior; barbels not margined, 
the two mental barbels remote from each other, below the angle of the mouth; gill- 
membranes overlapping; about twelve branchiostegals ; gill-rakers very short; 
fontanel reaching to the base of the occipital process; coalesced vertebrae with 
broad lateral processes; no dorsal or pectoral spines; eye without a free orbital 
margin ; anal very long. 

78. Helogenes marmoratus Gunther. (Plate XXII, fig. 2.) 
"Asicurrupa" (of the natives about the Kaieteur). 

Helogenes marmoratus Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 
(Essequibo); Catalogue, V, 1864, 66 (Essequibo). — Eigenmann, Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 398. 
This species has been taken but once before. 
Fifteen specimens, 39-82 mm. Creeks about Aruataima. (C. M. Cat. No. 

1703a-c; I. U. Cat, No. 12085.) 

Nineteen specimens, 39-71 mm. Creeks about Holmia. (C. M. Cat. No. 

1704a-c; I. U. Cat. No. 12086.) 

Eleven specimens, 68-86 mm. Potaro Highland. (C. M. Cat. No. 1705a-c; 

I. U. Cat. No. 12087.) 



208 MEMOIRS OF THE CARNEGIE MUSEUM 

Fourteen specimens, 40-82 mm. Potaro Highland. (C. M. Cat. No. 1706a-c; 
I. U. Cat. No. 12088.) 

Fourteen specimens, 32-80 mm. Creek at Tukeit Landing. (C. M. Cat. No. 
1707a-c; I. U. Cat. No. 12089.) 

This species is preeminently a species of the Guiana Plateau. The only place 
in the lowlands (with one doubtful exception) where it was secured is Tukeit, a short 
distance below the Kaieteur. Giinther records this or a related species from the 
Essequibo. One specimen whose label was lost may have come from Kumaka. 

Head 5.75-6.25; depth 4.25; D. 5 or 6; A. 37-40; V. 6. Eye 3 in snout, 8 in 
head, 4 in the distance between the eyes. 

Head short, rounded, its width about equal to its length, its depth about equal 
to its length without the snout, covered with thick skin above. Maxillary barbel 
fitting into a groove below the eye, extending to or a little beyond the middle of the 
pectoral; mental and post-mental barbels close together, the mental barbel opposite 
the maxillary barbel, reaching to the tip of the pectoral; the post-mental a little 
shorter. Gill-membranes broad, overlapping, covered in front by a recurved fold 
of skin. Dorsal small, rounded, equidistant from caudal and occiput or a little 
nearer the latter; adipose fin very small, its distance from the dorsal equal to the 
length of the head; caudal broad, slightly forked, lower lobe the longer, about 3.5-4 
in the length; distance from snout to anal about 1.25 in the length of the anal; anal 
margin rounded behind, the rest of its margin straight or but slightly rounded; 
ventrals reaching anal; pectorals to the ventrals. 

Reddish brown, variously marbled; base of caudal dark, the fin then abruptly 
lighter; fins, especially the dorsal, ventrals and pectorals hyaline-margined. 

Family V. HYPOPHTHALMIDiE. 

< Siluridce anomalopterce Gunther, Catalogue, V, 1864, 3. 

= Hypophthalmidce Cope, Proc. Am. Assoc. Adv. Sci., XX, 1871, 331. 

Dorsal over the anal, anal very long, its origin near the origin of the second 
third of the body. Eye placed low, the optic nerve ascending beneath the skin; a 
minute air-bladder on either side of the coalesced vertebrae, enclosed by their lateral 
processes, the scapula, and the process connecting the scapula with the basi-occipital. 

Hypophthalmus Spix. 

Hypophthalmus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 16, pi. 9 (sp.). — - 
Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 109 (edentatus). 

Notophthalmus Hyrtl, Denkschr. Akad. Wiss. Wien, XVI, 1859, 17 (marginatus = 
edentatus). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 209 

Pseudohypophthalmus Bleeker, Nederl. Tijdschr. Dierk., 1, 1863, 109 (fimbriatus = 
edentatus) . 
Type, Hypophthalmus edentatus Spix. 

79. Hypophthalmus edentatus Spix. 

Hypophthalmus edentatus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 16, pi. 9 
(equatorial Brazil). — Gunther, Catalogue, V, 1864, 67 (copied). — Cope, Proc. 
Am. Philos. Soc, XVII, 1878, 673 (Peruvian Amazon). — Eigenmann and 
Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 120 (Para); Occasional Papers 
Cal. Acad. Sci., I, 1890, 313.— Eigenmann and Bean, Proc. U. S. Nat. Mus., 
XXXI, 1907, 664 (Amazon). — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 398. 

Hypophthalmus marginatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 
1840, 225, pi. 439 (Cayenne; Surinam).— Gunther, Catalogue, V, 1864, 68 
(copied).— Vaillant, Bull. Soc. Philom., (7), IV, 1880, 150 (Calderon).- 
Wright, Trans. Roy. Soc. Canada, III, sect, iv, 1886, 107-118, pis. 8-10 
(important paper on structure). — Perugia, Ann. Mus. Genova, (2), X, 1891, - 
(Chaco Centrale). 

N otophthalmus marginatus Hyrtl, Denkschr. Akad. Wiss. Wien, XVI, 1859, 17 
(vertebrae 2 + 5 + 54). 

Hypophthalmus longijilis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

230 (Surinam). — Gunther, Catalogue, V, 1864, 68 (Demerara; Surinam).— 
Bleeker, " Silures de Suriname," 1864, 88 (Surinam). 

Hypophthalmus spixii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

231 (copied).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 446 (Rio Branco). 
Hypophthalmus cdentulus Castelnau, Anim. Am. Sud, Poiss., 1855, 47. 
Hypophthalmus Jlmbriatus Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 444, pi. 9, 

fig. 30 (Rio Negro). — Gunther, Catalogue, V, 1864, 68 (copied). 
Hypophthalmus perporosus Cope, Proc. Am. Philos. Soc, XVII, 1878, 673 

(Nauta). — Steindachner, " Flussfische Sudamerika's," iv, 1882, 4 (Rio 

Huallaga; Rio Amazonas). 

Thirteen specimens, 270-485 mm. Wismar. (C. M. Cat. No. 1701a-c; I. 
U. Cat. No. 12084.) 

One specimen, 445 mm. Morowhanna ? (C. M. Cat. No. 1702.) 

Head 3.8-4; depth 4.6-5; D. 1,6; A. 64-6S; eye about 10 in head; 5 in snout. 

Much compressed, snout depressed, head rounded above, its lower surface 
flat, the eye at the lower margin of the head; jaws equal, the upper papery, the 



210 MEMOIRS OF THE CARNEGIE MUSEUM 

lower heavier; no teeth; barbels all broadly fringed, the maxillary barbel about 
reaching tip of pectoral. 

The four mental barbels but little shorter than the maxillary ; gill-membranes 
widely separate, gill-rakers very numerous, 2-2.5 times as long as eye. 

Dorsal small, nearer adipose than to tip of snout, widely separate from the 
occipital crest; base of adipose 1.5 times as long as eye; caudal forked; pectorals 
reaching to or beyond tips of ventrals and beyond origin of anal; anal very long, 
about 2 in the length. Upper part of head and sides above lateral line steel-blue, 
white below; pectoral, dorsal, and caudal dusky; anal white or nigrescent. 

Family VI. PYGIDIID^. 20 

> Siluroidei trichomycteriformes Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 112. 

> Siluridce opisthopterce Gunther, Catalogue, V, 1864, 4. 

> Siluridcv branchicolm Gunther, Catalogue, V, 1864, 4. 

= Tricho?nycteridcc Gill, Arrangement of the Families of Fishes, 1872, 19. 
= Pygidiidce Eigenmann and Eigenmann, Am. Nat., XXII, 1888, 649. 
The characters are given in the key to the families, page 119. 

Key to the Guiana Genera of Pygidiidce. 
a. Dorsal entirely in front of the ventrals; vomer with a series of conical teeth on each side; eye without 
free orbital margin; a maxillary and two pairs of mental barbels; each jaw with a narrow band 

of conical teeth. (CctopsiiKE.) Hemicetopsis. 

aa. Dorsal behind the ventrals; no teeth on vomer. 

6. Mouth terminal, maxillary with two barbels of about equal size; a nasal barbel; gill-membranes 

free. (Pygidiinw.) Pygidium. 

66. Mouth inferior, very wide; one of the maxillary barbels minute; no nasal barbel; gill-membranes 
broadly united with the isthmus. (Stegophilince.) Ochmacanthus. 

Subfamily Cetopsin^e. 

Hemicetopsis Bleeker. 

Hemicetopsis Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 111. 

Type, Cetopsis candiru Agassiz. 

Dorsal in front of the ventrals; teeth conical, those on the vomer in a single 

series. 

Key to the Guiana Species of Hemicetopsis. 

a. Gill-membrane very broadly united to the isthmus, the gill-opening extending as far below as above 

the pectoral; posterior margin of the eye at the end of the first third of the head; ventrals scarcely 

reaching anus; head subglobose; chromatophores of the sides with their branches spreading 

backward and forward only, not upward and downward; maxillary barbel about half as long 

as the head; Br. 10 macilentus. 

«° A family of mixed elements and hard to define. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 211 

aa. Gill-membranes scarcely united to the isthmus, extending much farther below than above the pec- 
toral; posterior margin of the eye near the middle of the head; ventrals reaching beyond anus; 
more slender; chromatophores of the sides radiating in all directions; maxillary barbels reaching 
the tip of the opercle, but little shorter than the head; mental barbels reaching the edge of the 
gill-membrane, post-mentals a little beyond the edge of the gill-membrane when laid straight 
back minutus. 

80. Hemicetopsis macilentus sp. nov. (Plate XXIII, fig. 1.) 

Type, 55 mm. Creek below Potaro Landing. (Carnegie Museum Catalog 
of Fishes No. 1726.) 

Cotype, 65 mm. Creek below Potaro Landing. (I. U. Cat. No. 12100.) 

Head 3.33; depth 3.8; D. 1,5; A. 23, V. 6; P. 1,7; eye 3 in snout, 8 in head, 
3 in distance between the eyes. 

Head short, blunt; tail compressed; width of head equals its length without 
the snout; head covered with loose skin, which is minutely papillose; upper jaw 
projecting, the mouth wide, 1.5 in the length of the head; teeth hard, conical, those 
in the jaws in narrow bands, those on the vomer larger, in a single series, with some- 
times an extra tooth near the end of the row; maxillary barbel about half the 
length of the head; space between gill-openings 2.5 in the length of the head. 

Dorsal spine a little less than one-third the length of the head; caudal fin 
short, forked, the lobes about 4.5 in the length; ventrals free from each other and 
from the belly; pectoral spine about one-fifth of the length of the head. 

Upper surface of head gray; sides with numerous chromatophores, whose rays 
branch forward and backward from the center of the cell, giving a strigose effect 
and looking like little bundles of sticks tied in the middle, hence the name. 

81. Hemicetopsis minutus sp. nov. (Plate XXIII, fig. 2.) 

Type unique, a specimen 22 mm. long. Amatuk Cataract. (Carnegie Mu- 
seum Catalog of Fishes No. 1728.) 

Differs from macilentus in having the color-cells regularly stellate, the ventrals 
reaching to origin of anal (to anus in H. macilentus) and the gill-membranes very 
narrowly united to the isthmus, almost free; barbels all reaching the gill-opening 
when laid straight back; posterior margin of the eye near the middle of the head 
(at the end of the first third in H. macilentus). 

Subfamily Pygidiin^e. 
Pygidium Meyen. 
Trichomycterus Valenciennes, in Humboldt, Rec. Obs. Zool., II, 1833, 348 
(nigricans), not Thrichomycterus Humboldt. 



212 MEMOIRS OF THE CARNEGIE MUSEUM 

Thrychomycterus Cuvier and Valenciennes, Hist. Nat. Poiss., XVIII, 1846, 485 

(misquoted ) . 
Thrichomycterus Girard, U. S. Nav. Astron. Exped., II, 1855, 242 (misquoted). 
Pygidium Meyen, Reise in Peru, I, 1835, 475 (fuscum). 

Type, Pygidium fuscum Meyen. 

Origin of the dorsal over or in front of the origin of the short anal; gill-mem- 
branes free from the isthmus; mouth terminal; ventrals present; two maxillary 
barbels; nasal barbels; opercle and preopercle with osseous prickles. 

Key to the Guiana Species of Pygidium. 

a. Origin of dorsal in front of the vertical from the origin of the anal; maxillary barbel reaching tip of 

opercle; snout about 2.5 in the head; nasal barbel reaching not quite to the tip of the maxillary 

barbel. 

b. Head 6 in the length; the first pectoral ray with its filament equals the length of the head; sides 

and back with numerous spots, each larger than the eye, in about five series between the 

dorsal and anal guianense. 

bb. Head 5 in the length; first pectoral ray with its filament equals the length of the head without 

the opercle; uniform yellowish brown above, lighter below; top of head marbled . . . conradi. 

aa. Origin of anal under origin of dorsal, head 6 in the length; maxillary barbel reaching tip of pectoral, 

outer pectoral ray with its filaments equals the head in length; upper parts obscurely 

spotted gracilior. 

82. Pygidium guianense Eigenmann. 

Pygidium guianense Eigenmann, Ann. Carnegie Mus., VI, 1909, 11 (Aruataima, 

on the Potaro); Repts. Princeton Univ. Exp. Patagonia, III, 1910, 400. 

This species is known from the type, taken in the cataracts of the Potaro River, 
above the Kaieteur. 

Type, 77 mm. Aruataima Falls, Upper Potaro. (Carnegie Museum Catalog 
of Fishes No. 1003.) 

Head 6; depth equals head in length; D. 9; A. 7; eye 4 in snout, 9.5 in head. 

Head nearly as broad as long; maxillary barbel reaching to tip of opercle; 
teeth in bands of about four irregular series; origin of anal under middle of dorsal; 
dorsal fulcra extending forward to near the dorsal; caudal rounded; first pectoral 
ray prolonged in a filament nearly as long as the rest of the ray; round dark spots 
everywhere, except on belly and lower surface of head; caudal dusky, the margin 
light. 

83. Pygidium conradi sp. nov. 

Pygidium guianense Eigenmann, Ann. Carnegie Mus., VI, 1909, 11, part (Ama- 
tuk and Waratuk) . 



eigenmann: the freshwater fishes of British guiana 213 

Type, 41 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 2212.) 

Cotype, 34 mm. Waratuk. (I. U. Cat. No. 11710.) 

These specimens were considered identical with guianense. The discovery of 
Pygidium gracilior makes it very probable that they are distinct. The differences 
are pointed out in the key. 

This species is named for Mr. Bernard S. Conrad. 

84. Pygidium gracilior sp. nov. 

Type unique, 27 mm. Erukin. (Carnegie Museum Catalog of Fishes 
No. 1730.) 

Head 6; depth 9; D. 8; A. 6; eye about 2 in the snout; interorbital a little 
greater than snout, snout 3 in the head. 

Slender, head as broad as long; maxillary barbel reaching tip of pectoral; 
nasal barbel to origin of pectoral; outer pectoral ray prolonged, about equal to 
the head in length. Origin of the anal under origin of dorsal; distance from origin 
of dorsal to origin of caudal 3.5 in the length; length of caudal 5 in the length. 

All upper parts obscurely spotted. 

Subfamily STEGOPHiLiNiE. 
Ochmacanthus 21 gen. nov. 

Type, Ochmacanthus flabelliferus sp. nov. 

In the Annals of the Carnegie Museum, IV, 118, I called attention to the fact 
that Stegophilus insidiosus and Stegophilus reinhardti "differ much from each other 
in the caudal fulcra and may represent two distinct genera." A new species from 
Guiana with the structure of reinhardti may be utilized to furnish a diagnosis of 
the new genus. 

Two maxillary barbels, one of them minute; mouth large, wholly inferior; dorsal 
over anal; fully developed caudal rays much diverging from a narrow base; caudal 
fulcra greatly developed; eye above the mouth. 

85. Ochmacanthus flabelliferus sp. nov. 
Type, 33 mm. Konawaruk. (Carnegie Museum Catalog of Fishes No. 1729.) 
Cotypes, two specimens, 34 and 35 mm. Konawaruk. (I. U. Cat. No. 12111.) 
Head 5.33; depth 7; D. 8; A. 7; eye 1 in snout, 3.75 in head, 1 in space 

between the eyes. 

Width of head equal to its length; snout semicircular in outline, the head 

depressed; mouth very wide, its width equal to the length of the head less half the 

21 flx/uos, series, inavda, thorn. 



214 MEMOIRS OF THE CARNEGIE MUSEUM 

snout; upper jaw with three series of teeth; teeth of the two outer series conical, those 
of the inner series broad, removed from the others, forming a solid palisade; no labial 
teeth; lower jaw with an outer series of long, curved, claw-like teeth in the lip, 
and four series in the jaw, of which the first is short, near the middle, the second 
extends farther to the sides, the third is longest, extending from the middle to the 
side of the jaw, the fourth is shorter again and confined to the sides, not reaching 
the median line of the jaw. Preopercle with nine claw-like erectile spines; opercle 
somewhat prolonged, earning a bunch of nine spines similar to those of the pre- 
opercle above and behind the gill-opening. Gill-opening small, entirely above the 
level of the middle of the pectoral; outer maxillary barbel about as long as the 
eye, the inner one minute. 

Pectorals partly adnate; ventrals small, free, reaching anal; dorsal about equal 
to the anal and but slightly farther forward. 

Light, with numerous chromatophores more or less aggregated in places; a 
black spot on base of caudal. 

Family VII. CALLICHTHYID.E. 

= Callichthyoidei Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 82. 

< Siluridce proteropodes Gunther, Catalogue, V, 1864, 4 (Hypostomatince in part.) 

= Callichthyidce Gill, Arrangement of the Families of Fishes, 1872, 19. — Eigen- 

mann and Eigenmann, Occasional Papers Cal. Acad. Sci., I, 1890, 449. 

Distinguished from all other fishes by the double series of dermal plates meeting 
along the middle of the sides. A small homogeneous group, confined to South 
American waters. 

Key to the Guiana Genera of Callichthyidje. 

a. Two pairs of nuchal plates between occiput and dorsal plate; suture between humeral and coracoid 

processes extending almost horizontally to the posterior margin of the pectoral armature; a 

large opening between coracoid and clavicle below and in front of the pectoral spine. 

b. Coracoid covered with skin. Sides of the head without bristles; no mental barbels; lower jaw 

with small bands of teeth on the sides; a naked area along dorsal and ventral surfaces; 

suborbital bones concealed; dorsal spine rudimentary; caudal rounded Callichthys. 

bb. Coracoid exposed below; coracoid bone joined to the clavicle for its whole length. Two barbels at 

each rictus, none at the symphysis. Lower lip without barbels; a naked area along ventral 

surface; caudal rounded or emarginate; dorsal spine low and flat; pectoral spine serrate on 

inner margin in the young, outer margin and surfaces covered with bristles. . . Hoplosternum. 

aa. Occipital with a narrow process extending to the dorsal plate. D. 1,6-8; coracoid process exposed; 

suture between coracoid and humeral processes extending from the large pectoral pore obliquely 

downward and backward to the ventral margin of the pectoral armature; dorsal and pectoral 

spines long, pungent, their outer surfaces smooth Corydoras. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 215 

Callichthys Linnaeus. 
Callichthys Linn.eus, Amoen. Acad., I, 1754, 317. — Cuvier and Valenciennes, 

Hist, Nat. Poiss., XV, 1840, 294 (asper = callichthys). — Bleeker, Nederl. 

Tijdschr. Dicrk., I, 1863, 82 (tamoata = callichthys) . 
Cataphractus Bloch, Ausl. Fische, VIII, 1794, 80 (preoccupied in mammals). — 

Lacepede, Hist. Nat, Poiss., V, 1804, 124 (callichthys). — Swainson, Class. 

Fishes, Amph., and Rept., II, 1839, 304 (depressus = callichthys). 

Type, Silurus callichthys Linnaeus. 

Characters given in the key to the genera. 

86. Callichthys callichthys Linnaeus. 

Callichthys tamoata Linnaeus, Mus. Adolphi Fred., 1754, 731. — Bleeker, " Silures 
de Surlname," 1864, 22 (Surinam). 

Silurus callichthys Linnaeus, Syst. Nat,, ed. 10, I, 1758, 307 (America); ed. 12, 
I, 1766, 506.— Gmelin, Syst. Nat., I, iii, 1788, 1361. 

Cataphractus callichthys Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 
1888, 164 (Rio Janeiro; Pernambuco; Juiz de Fora; Bahia; Mendez; Macacos; 
Porto Seguro; Surinam). 

Callichthys callichthys Eigenmann and Eigenmann, Occasional Papers Cal. Acad. 
Sci., I, 1890, 452. — von Ihering, Siisswasserfische d. Rio Grande do Sul, 1893, 
21.— Eigenmann, Ann. N. Y. Acad. Sci., VII, 1894, 633 (Rio Grande do Sul) — 
Lahille, Rev. Mus. de la Plata, VI, 1895, 272 (Puerto Viejo). — Pellegrin, 
Bull. Mus. d'Hist, Nat., 1899, 158 (Apure). — Eigenmann, Ann. Carnegie 
Mus., IV, 1907, 123 (Bahia Negra); Repts. Princeton Univ. Exp. Patagonia, 
III, 1910, 402. 

Callichthys asper Quoy and Gaimard, Voy. Uranie et Physicienne, Zool., 1824, 
232. — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 302 (Cayenne; 
Rio Janeiro).— Kner, SB. Akad. Wiss. Wien, XVII, 1855, 107 (Para Rio; 
Surinam; Bahia). — Castelnau, Anim. Am. Sud, Poiss., 1855, 38 (Bahia; name 
only). — Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 53. — Gunther, Catalogue, 
V, 1864, 226 (Bahia; Para).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 
681 (Nauta).— Perugia, Ann. Mus. Genova (2), X, 1891, 636 (Chaco 
Centrale) . 

Cataphractus depressus Swainson, Class. Fishes, Amph., and Rept.", II, 1839, 304 
(based on Bloch, pi. 377). 

Callichthys ccelatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 308 
(Rio Janeiro). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 
630 (trenches). — Gunther, Catalogue, V, 1864, 227 (copied). 



216 MEMOIRS OF THE CARNEGIE MUSEUM 

( 'allichthys Iceviceps Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 
309 (= male). 

Callichthys loricatus Gronow, Cat. Fish., ed. Gray, 1854, 157. 

Callichthys hemiphractus Hensel, Archiv fi'ir Naturg., I, 1868, 374 (Costa da Serra; 
= the young) . 
Ten specimens, 69-142 mm. Small Creek at Holmia. (C. M. Cat. No. 1570 

a-c; I. U. Cat. No. 11985.) 

One specimen, 129 mm. Chipoo Creek. (C. M. Cat. No. 1571.) 

One specimen, 106 mm. Nickaparoo Creek. (C. M. Cat. No. 1572.) 

Seven specimens, 117-149 mm. Upper Essequibo. (C. M. Cat. No. 1573 

a-b; I. U. Cat, No. 11986.) 

Fifteen specimens, 60-129 mm. Kumaka. (C. M. Cat. No. 1574a-c; I. U. 

Cat, No. 11987.) 

One specimen, 125 mm. Pacopoo Pass. (C. M. Cat, No. 2208.) 

I have also examined the specimens recorded by Bleeker, and now in the 

Leiden Museum, and those in Amsterdam. 

28— 29 
Head 4; depth 4.66-5, equal to its width; D. 1,6; A. 5.5; plates 9fi _ 9 o • 

Head depressed, tail compressed; eye 6.5-8 in interorbital; inner rictal barbel 
reaching to near or beyond the tip of the humeral process; nuchal plates about 
twice as wide as the plates immediately behind them; snout broad, rounded; no 
teeth in the upper jaw, those in the lower jaw interrupted in the middle, confined 
to the side of the jaw. About fourteen small azygous plates in front of the adipose; 
fins all rounded. Uniform ashy or slaty, or more or less mottled or spotted; no 
definite markings. 

HOPLOSTERNUM Gill. 

( 'allichthys Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 294 (sp.). 
Hoplosternum Gill, Ann. Lye. Nat. Hist. N. Y., "NT, 1858, 395 (loevigatum = 

littorale). 

Type, Callichthys Icevigatus Valenciennes. 

Characters given in the key. 

Key to the Guiana Species of Hoplosternum. 
a. Caudal deeply emarginate; eight or nine azygous plates in front of the adipose, usually one between 
each pair of plates; one. rarely two, pairs of plates behind the dorsal without the azygous plates; 
three pairs of plates between occipital and dorsal. Uniform dark brown or black., .littorale. 
mi. Caudal rounded or but slightly emarginate; the azygous plates usually more numerous than the 
pairs of plates they separate; several pairs of plates meeting behind the dorsal; two pairs of 
plates between occipital and dorsal, the second pair notched to receive the dorsal fulcrum. 
Sides spotted or mottled thoracatum. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 217 

87. Hoplosternum littorale (Hancock). (Plate XXIV, fig. 1.) 

Callichthys littoralis Hancock, Zool. Journ., IV, 1828, 244 I Demerara). — Gunther, 
Catalogue, V, 1864, 227 (Dcmerara; British Guiana; Trinidad). — Lutkex, 
Vid. Med. Naturhist. For. Kjobenhavn, 1874, 215 (Trinidad).— Vaillant, Bull. 
Soc. Philom., (7), IV, 1880, 165 (Calderon).— Steindachner, " Flussfische 
Siidamerika's," iv, 1882, 6 (Rio Huallaga). — Jordan, Proc. U. S. Nat. 
Mus., IX, 1886, 559 (name only). — Boulenger, Ann. Mus. Genova (2), 
XIX, 1898, 126 (Puerto 14 de Mayo).— Vaillant, Nouv. Arch. Mus. d'Hist. 
Nat,, (4), II, 1900, 124 ( Carsevenne) . 

Hoplosternum littorale Eigenmann and Eigenmann. Proc. Cal. Acad. Sci., (2), I, 
1888, 164 (Surinam; Gurupa; Para; Santarem; Tabatinga; Arary; Silva, Lake 
Saraca; Villa Bella; Porto do Moz; Lake Hyamary; Ueranduba); Occa- 
sional Papers Cal. Acad. Sci., I, 1890, 456. — Berg, An. Mus. Nac. Buenos 
Aires, IV, 1895, 136. — Eigenmann and Kennedy, Proc. Acad. Nat, Sci. 
Phila., 1903, 504 (Arroyo Carumbey and Yajamar; Estancia la Armonia). — ■ 
Eigenmann, Ann. Carnegie Mus., IV, 1907, 123 (Bahia Negra); Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 402. 

Callichthys subulahis Ctjvier and Valenciennes, Hist, Nat. Poiss., XV, 1840, 311 
(Cayenne; Buenos Ayres). 

Callichthys Uevigatus Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 
pi. 5, fig. 2. — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 314 
(Buenos Ayres; Trinite).— Kner, SB. Akad. Wiss. Wien, XVII, 1855, 109 
(no locality). — Perugia, Ann. Mus. Genova (2). X, 1891, 636 (Tucuman). 

Hoplosternum lavigatum Gill, Ann. Lye. Nat, Hist. N. Y., VI, 1858, 396 
(Trinidad). — Bleeker, " Silures de Suriname," 1864, 24 (Surinam). 

Callichthys alMdus Cuvier and Valenciennes, Hist. Nat, Poiss., XV, 1840, 316 
(Cayenne) . 

Hovlosternum stevardii Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 401 (Trinidad). 
One specimen, 192 mm. Mahaica, (C. M. < at. No. 1575.) 
Seventeen specimens, about 164-180 mm. Georgetown market. (C. M. Cat, 

No. 1576«-e; I. U. Cat, No. 11988.) 

Two specimens, about 188 mm. Botanic Garden. (C. M. Cat, No. 1585a; 

I. U. Cat, No. 11993.) 

25 
Head 3.4-3.5; depth 3.25; D. 1,8; A. 11,5.5. Plates ^. 

Snout somewhat pointed, depressed; dorsal profile a little more arched than 
the ventral; eye about 5 in interorbital; inner rictal barbel reaching to tip of 



218 MEMOIRS OF THE CARNEGIE MUSEUM 

pectoral; nuchal plates about one-fifth wider than the plates immediately following; 

no teeth; about eight azj'gous plates between the dorsals, generally corresponding 

to the lateral plates; uniform slaty blue or black. 

Dorsal rounded, caudal deeply emarginate, the outer rays prolonged; other 

fins lanceolate. 

88. Hoplosternum thoracatum (Cuvier and Valenciennes). (Plate XXIV, fig. 2.) 

Callichthys thoracatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 
309, pi. 443 (Mana; Martinique) .—Peters, MB. Akad. Wiss. Berlin, 1877, 471 
(San Fernando de Apure).— Kner, SB. Akad. Wiss. Wien, XVII, 1855, 108 
(Surinam). — Gunther, Catalogue, V, 1864, 228 (copied). — Jordan, Proc. 
U. S. Nat, Mus., IX, 1886, 559 (name only). 

Callichthys (Hoplosternum) thoracatus Steindachner, " Fisch-Fauna des Cauca," 
etc., 1880, 14 (Cauca). 

Hoplosternum thoracatum Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 396.— 
Bleeker, " Silures de Suriname," 1864, 26 (Surinam). — Eigenmann and Eig- 
enmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 164 (Curupira; Tabatinga; Cudajas; 
Gurupa; Teffe; Lake Hyamary; Villa Bella; Para; Ueranduba; Porto do Moz; 
Pemambuco; Obidos). — Eigenmann and Bean, Proc. U. S. Nat. Mus., 
XXXI, 1907, 665 (Amazon). — Eigenmann, Repts. Princeton Univ. Exp. 
Patagonia, III, 1910, 402. 

Callichthys lotujifilis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1849, 
317 (Cayenne). — Schomburgk, Fishes Brit, Guiana, I, 1841, 150, 151, 154, 
drawings No. 22 (Curassarraka). — Gunther, Catalogue, V, 1864, 228 (Suri- 
nam; River Cupai). 

Hoplosternum longifdis Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 396 (Trini- 
dad).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 681 (Nauta).— Bleeker, 
"Silures de Suriname," 1864, 27 (Surinam). 

Callichthys personatus Ranzani, Nov. Com. Acad. Scient, Insti. Bonon., V, 1842, 
322, pi. 24. 

Callichthys exaratus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 630 
(Guiana). 22 

Callichthys pictus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 630. 

Callichthys sulcatus Kner, SB. Akad. Wiss. Wien, XVII, 1855, 110 (Rio Branco 
and Marabitanos) . 

? Callichthys chiquitos Castelnau, Anim. Am. Sud, Poiss., 1855, 38, pi. 18, fig. 2 
(Chiquitos). 

22 In the type of this species there are four azygous plates separating as many paired plates in 
front of the second dorsal. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 219 

Thirteen specimens, 97-98 mm. Chipoo Creek. (C. M. Cat. No. 1577a-e 
and 1583a-6; I. U. Cat. No. 11989.) 

One specimen, 105 mm. Packeoo Falls. (C. M. Cat, No. 1578.) 

Seventy-four specimens, 58-109 mm. Gluck Island. (C. M. Cat. No. 
1579a and 1580o-o; I. U. Cat. No. 11990.) 

Five specimens, 61-120 mm. Kumaka. (C. M. Cat. No. 1581a-6; I. U. 
Cat. No. 11991.) 

Three specimens, 114-124 mm. Mud creek in Aruka. (C. M. Cat, No. 
1582a; I. U. Cat. No. 11992.) 

One specimen, 158 mm. Botanic Garden, Georgetown. (C. M. Cat. No. 
1584.) 23 

I have also seen the specimens in the Leiden Museum and the Museum at 

Amsterdam. 

25-26 
Head 3.5-4; depth 3.16-3.66; D. 1,8; A. 1,6-8; plates ^-^. 

There is considerable variation in shape and color. Snout depressed, more 
pointed than in thoracatum. Eye 5.5-6 in interorbital; nuchal plates as wide as, or 
half as wide again, as the plates following them, which are notched to receive the ful- 
crum of the dorsal; inner rictal barbels extending past origin of ventrals, sometimes 
past their tip. Four to six (in Aruka River specimens) or seven to eight azygous 
plates between the lateral plates in front of the adipose dorsal ; four pairs of plates 
meet behind the dorsal ; depth in front of the adipose fin in some of the Chipoo speci- 
mens equals the length of the head, but more than an orbital diameter less than the 
head in Gluck Island specimens; dorsal rounded; caudal slightly emarginate when 
closed, truncate when opened. Sides spotted or mottled; ventral surface white, with 
more or less conspicuous black spots; dorsal and caudal spotted, the latter usually 
with a light bar at the base, the Gluck Island specimens with a broad dark median 
band, the tip of the caudal dusky. 

Two specimens in the Amsterdam Museum have the coracoids meeting along 

their entire length below. 

Corydoras Lacepede. 

Corydoras Lacepede, Hist. Nat. Poiss., V, 1803, 145 (geoffroyi = punctatus). 

Hoplisoma Swainson, Class. Fishes, Amph., and Rept., II, 1839, 304 (punctata). 

Hoplosoma Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 402 {punctata). 

Gasterodermus Cope, Proc. Am. Philos. Soc, XVII, 1878, 681 (type ?). 

Type, Corydoras geoffroyi Lacepede. 

Characters as given in the key. 

23 In this specimen the caudal is nearly uniform beyond the lighter bar at its base and there are but 
five azygous plates which correspond to paired plates. 



220 MEMOIRS OF THE CARNEGIE MUSEUM 

89. Corydoras punctatus (Bloch). (Plate XXIV, fig. 3.) 
Cataphractus punctatus Bloch, Ausl. Fische, VIII, 1794, pi. 377, fig. 2. — Bloch 

and Schneider, Syst. Ichth., 1801, 108. — Lacepede, Hist. Nat. Poiss., V, 1803, 

125 (Surinam). 
Hoplisoma punctata Swainson, Class. Fishes, Amph., and Rept., II, 1839, 304 

(name only). 
Callichthys punctatus Gunther, Catalogue, V, 1864, 229 (Essequibo). 
Corydoras punctatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 166 (Jose Fernandez).—? Perugia, Ann. Mus. Genova, (2), X, 1891, 

635 (Rio de la Plata). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 403. 
Corydoras gcoffroyi Lacepede, Hist. Nat. Poiss., V, 1803, 147 (locality ?). 
Corydoras ambiacus Cope, Proc. Acad. Nat. Sci. Phila., 1871, 280 (Ambyiacu River, 

Ecuador). 
Gasterodermus ambiacus Cope, Proc. Am. Philos. Soc, XVII, 1878, 681 (Nauta). 

Four specimens, 43-58 mm. Mud-flats of Demerara River. (C. M. Cat. No. 
1560a-6; I. U. Cat. No. 11977,) 

Three specimens, 48-52 mm. Erukin. (C. M. Cat, No. 1561a; I. U. Cat. 
No. 11978.) 

Sixteen specimens, 28-40 mm. Malali. (C. M. Cat. No. 1562a-e; I. U. Cat. 
No. 11979.) 

One specimen, 45 mm. Below Packeoo Falls. (C. M. Cat. No. 1563a). 

Two specimens, 29-36 mm. Tumatumari. (C. M. Cat, No. 1564a; I. U. 
Cat, No. 11980.) 

Twenty-nine specimens, 39-54 mm. Creek below Potaro Landing. (C. M. 
Cat, No. 1565a-e; I. U. Cat, No. 11984.) 

Two specimens, 50 mm. Kumaka. (C. M. Cat. No. 1566a; I. U. Cat. No. 
11981.) 

One specimen, 29 mm. Wismar. (C. M. Cat, No. 1567a.) 

Sixteen specimens, 29-45 mm. Konawaruk. (C. M. Cat. No. 1568a-e; I. U. 
Cat, No. 11982.) 

Sixteen specimens, 28-38 mm. Rockstone sand-bank. (C. M. Cat. No. 

1569a-e; I. U. Cat. No. 11983.) 

24 23 
Head 3.25-3.33; depth 2.6-3; D. 1,7-8; A. 1,6 or 1,7; plates ^ °r gj. 

Profile strongly curved; eye 3.5-4 in the head; maxillary barbels reaching 
lower angle of gill-opening or shorter. Origin of dorsal equidistant from tip of 
snout and tip of spine of adipose or upper caudal fulcra; dorsal spine smooth in 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 221 

front, roughened behind, nearly equal to, or slightly longer than, the pectoral spine. 
Three or four azygous plates in front of the adipose; caudal forked, the lobes a 
little longer than the head. 

Color variable; a more or less conspicuous black band across the head at the 
eyes; dorsal black, or partially or faintly so, the color sometimes continued on the 
sides, other fins hyaline. Sides profusely spotted, quite plain, or the plates mar- 
gined with black. 

Family VIII. LORICARIIDCE. 

< Siluroides Cuvier, Regne Animal, ed. 1, II, 1817, 199. 

= Goniodontes Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 1. 
= Loricata Kner, Denkschr. Akad. Wiss. Wien, VI, 1853, 75. 
= Loricaroidei Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 77. 

< H ypostomatina Gunther, Catalogue, V, 1864, 11. 

< Loricariidce Gill, Arrangement of the Families of Fishes, 1872, 19. 

= Loricariidce Eigenmann and Eigenmann, Am. Nat., XXII, 1888, 649; Occa- 
sional Papers Cal. Acad. Sci., I, 1890, 351. 
> Loricariida; Regan, Trans. Zool. Soc. London, XVII, 1904, 191. 

Sides and back and sometimes the lower surface covered with bony plates, 
which are sometimes provided with teeth-like spines. Mouth wholly inferior, 
provided with a broad disk-like lip. Maxillary bones thin, with a terminal barbel, 
which is partly united with the oval disk; no mental or nasal barbels. Teeth, if 
present, hooked and usually two-lobed at the tip; the active ones in a single series; 
premaxillaries separate from each other, box-shaped, and filled with numerous relay 
teeth; dentaries separate from each other and constructed like the premaxillaries. 
No teeth on the palate; no frontal or occipital fontanels. Dorsal fin present, 
situated on the abdominal portion of the vertebral column, and not connected 
with the occipital by processes. Adipose fin, if present, composed of a spine and a 
thin membrane. Anal fin short. Gill-membranes joined to the isthmus, the gill- 
openings restricted to the sides. Intestinal canal elongate, coiled upon itself. 

Key to the Guiana Genera of Loricariidce. 
a. Tail short; caudal peduncle compressed, cylindrical, or moderately depressed; haemal spines all 
simple; lower, and fourth upper pharyngeals not tool lied; belly naked, or with minute granular 
plates; intestinal canal very long. (Plecostomince.) 
b. Premaxillaries and dentaries nearly equal in length. 

c. Opercle and interopercle little and not independently movable; snout granular to its margin. 
(I. Adipose fin present. 

e. Sides and back covered with plates; dorsal with seven rays Plecostomus. 

ee. Sides and back covered with plates; dorsal with thirteen rays Pterygoplichthys. 



222 MEMOIRS OF THE CARNEGIE MUSEUM 

' eee. Sides and back mostly naked, with a few minute plates near the tail. . .Lithogenes. 
dd. No adipose fin; a low crest between the dorsal and caudal; margin of snout and head 

granular Corymbophanes. 

cc. Interopercle movable, usually with spines or bristles. 

/. Snout granular to its margin, or with bristles; D. 1,6 or 7. 

g. Sides of the head without bristles Hemiancistrus. 

gg. Sides of the head with bristles, short in the female, much longer in the male. 

Pseudancistrus. 
//. Snout naked. 

ft. No tentacles Xenocara. 

hit. Snout with tentacles Ancistrus. 

bb. Premaxillaries much shorter than the dentaries and with fewer teeth, not united. Much 

depressed, of small size Lithoxus. 

aa. Tail long, depressed, with a single series of plates on the sides; intestinal canal usually not much 
longer than the body. .Haemal spines of the vertebrae above the anal bifid; lower and fourth 
upper pharyngeals toothed. (Loricariinw.) 
i. Teeth in the jaws in small or moderate number, not setiform; a more or less distinct orbital notch. 
j. Snout rounded or pointed, not much produced. 

k. Lips with numerous cirri and marginal fringes; no distinct anal plate Loricaria. 

kk. Lips papillose; a distinct anal plate Loricariichthys. 

jj. Snout produced, with a long rostrum. 

/. Snout expanded at the tip, with recurved hooks Hemiodontichthys. 

(II. Snout not expanded Reganella.)* 

ii. Teeth numerous, setiform; orbit circular, without a distinct notch. 
to. Dorsal opposite the ventrals. 

n. Snout rounded, not produced as a rostrum Harttia. 

(nn. Snout produced into a rostrum. Sides of the head in the male margined with bristles. 

Sturisoma.) 
toto. Dorsal opposite the anal. Very slender Farlowella. 

Subfamily Plecostomin^e. 

Plecostomus Gronow. 

Plecostomus Gronow, Mus. Ichth., 1, 1754, 24; Zoophyl., 1763, 127 (sp.). — Bleeker, 

Nederl. Tijdschr. Dierk., I, 1863, 77 (brasiliensis) . 
Hypostomus Lacepede, Hist. Nat. Poiss., V, 1803, 144 (guacari). — Cuvier and 

Valenciennes, Hist. Nat. Poiss., XV, 1840, 489 (plecostomus). 

Type, Plecostomus brasiliensis Bleeker = Plecostomus plecostomus (Linnaeus). 

Snout granular; no spines or bristles about head; an adipose fin; sides and 
back completely covered with plates. 

A genus of over twenty species, four of which have been recorded from Guiana. 

* Extralimital genera and species, when included in the tables, are in parentheses. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 223 

Key to the Guiana Species of Plecostomus. 

a. Occipital bordered by a single nuchal plate. 

b. Length of mandibular ramus 2.4-4 in interorbital; color of upper and lower caudal lobes almost 

alike, spotted in the adult, barred in the young. Lower surface of head and body almost 
completely covered with granules in the adult; outer caudal rays greatly prolonged, some- 
times three times as long as the shortest. plecostomus. 

bb. Length of mandibular ramus 2 in interorbital. Lower caudal lobe dark, plain; sometimes the 
entire caudal plain, sometimes the upper lobe spotted; lower surface naked (except some- 
times in the largest specimens a few granular plates between the pectorals); outer caudal 

rays scarcely more than thrice the length of the middle one hemiurus. 

(bbb. Lower surface and head completely covered with granular plates in specimens 205 mm. long; 

mandibular ramus 2 in interorbital; twenty-seven or twenty-eight scutes robini.) 

aa. Occipital bordered by a median nuchal plate, and one or several small plates on each side. 

c. Caudal peduncle normally formed, the scutes of the fourth series not strongly angulated. 

watwata. 
cc. Caudal peduncle broad and flat below, the scutes of the fourth series strongly angulated. 

emarginatus. 

90. Plecostomus plecostomus (Linnaeus). 

Loricaria plecostomus Linnaeus, Syst. Nat., ed. 12, I, 1766, 508 (America).— 
Gmelin, Syst. Nat., I, iii, 1788, 1363.— Bloch, Ausl. Fische, VIII, 1794, pi. 
374.— Bloch and Schneider, Syst. Ichth., 1801, 124. — Hyrtl, Denkschr. 
Akad. Wiss. Wien, XVI, 1859, 18. 

Hypostomus plecostomus Schomburgk, Fishes Brit. Guiana, I, 1841, 139 (Rio 
Braneo). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 643 
(Takutu and Rio Braneo). — Kner, Denkschr. Akad. Wiss. Wien, VII, 1853, 
263 (Ypanema; Mattogrosso; Barra do Rio Negro; Surinam). 

Plecostomus plecostomus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 
I, 1888, 169; Occasional Papers Cal. Acad. Sci., I, 1890, 406 (Silva, Lake 
Saraca; Para; Hyavary; -Coary; Rio Puty). — Kindle, Ann. N. Y. Acad. 
Sci., VIII, 1895, 253 (Marajo on Rio Tocantins).— Lahille, Rev. Mus. la 
Plata, VI, 1S95, 272 (Island Santiago).— Eigenmann and Bean, Proc. U. S. 
Nat. Mus., XXXI, 1907, 665 (Amazon).— Eigenmann, Ann. Carnegie Mus., 
IV, 1907, 122 (Corumba; Asuncion; Rio Apa; Arroyo Trementina); Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 403. 

Hypostomus guacari Lacepede, Hist. Nat. Poiss., V, 1803, 145 (America). 

Loricaria flava Shaw, Gen. Zool., V, 1805, 38, pi. 101. 

Plecostomus flavus Vaillant, Bull. Soc. Philom., (7), IV, 1880, 155 (Calderon). 

Plecostomus bicirrhosus Gronow, Cat. Fish, ed. Gray, 1854, 158. — Gunther, 
Catalogue, V, 1864, 231 , part. — Kner and Steindachner, Abhandl. K. Bayer. 



224 MEMOIRS OF THE CARNEGIE MUSEUM 

Akad., II Kl., X, 1S65, 60.— Hensel, Archiv fur Naturg., XXXVI, 1870, 75 

(Rio Cadeo). — Steindachner, " Flussfische Slidamerika's," ii, 1881, 109. 
Hypostomus robinii Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 46 (Trinidad). 
I'hcostomus brasiliensis Bleeker, " Silures de Suriname," 1864, 7 (Surinam). 
Plecostomus seminudus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

1888, 169 (Brazil); Occasional Papers Cal. Acad. Sci., I, 1890, 409. 
Plecostomus boulengeri Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 

1903, 502 (Paraguay). 

One specimen, 370 mm. Georgetown. (C. M. Cat. No. 1541.) 

One specimen, 14S mm. Kumaka. (C. M. Cat. No. 1542.) 

Three specimens, 164-210 mm. Wismar. (C. M. Cat, No. 1543a; I. U. Cat, 
No. 11962.) 

Head 3; depth 5-5.75; D. 1,7; A. 1,4; scutes 26; eye 6; interorbital 2.66 in 
the head; mandibular ramus 2.75 in the interorbital. 

Occipital with a blunt keel, bordered by a single plate behind; plates forward 
of the adipose largely keeled. 

Dorsal spine equal to pectoral spine, about equal to the length of the head; 
base of dorsal equal to its distance from the tip of the spine of the adipose. 

Reddish-brown, with olive spots, smallest on the head, absent on the belly; 
dorsal with a series of spots along the anterior part of the rays, sometimes confluent 
into bars, alternating with reddish bars. Caudal with alternating bars of olive 
and rusty. 

91. Plecostomus hemiurus sp. nov. (Plate XXV, fig. 1.) 
Plecostomus hemiurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 407 (name only). 

Type, 201 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1544.) 

Cotypes, four specimens, 158-180 mm. Amatuk. (C. M. Cat. No. 1545a; 
I. U. Cat. No. 11963.) 

Seven specimens, 27-113 mm. Waratuk. (C. M. Cat. No. 1546a-e; I. U. 
Cat, No. 11964.) 

Four specimens, 68-150 mm. Crab Falls. (C. M. Cat. No. 1547a; I. U. 
Cat. No. 11965.) 

Two specimens, 70-87 mm. Rockstone. (C. M. Cat, No. 1548; I. U. Cat. 
No. 11966.) 

One specimen, 71 mm. Gluck Island. (< !. M. Cat. No. 1549.) 

Two specimens, the larger 190 mm. Ireng ? (C. M. Cat, No. 1550; I. U. 
Cat. No. 11967.) 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



225 



One specimen, 132 mm. Botanic Garden. (C. M. Cat. No. 1586a.) 

This species differs from Plecostomus plecostomus notably in color and in the 
length of the mandibular ramus. 

Head 3; depth 5-5.5; D. 1,7; A. 1,4; scutes 25 or 26 + 1. Width of head 
an orbital diameter less than its length, its depth about 2 in the length, 3.5 in the 
snout; eye 6 in the head, interorbital 3; mandibular ramus 2 in the interorbital. 

Supraorbital slightly raised, a blunt median ridge on occipital forward to above 
eye; occipital bordered by a single plate; some of the plates distinctly, but feebly, 
keeled; ventral surface naked (except in the Ireng specimens, in which there are a 
few minute granular plates between the pectorals). 

Dorsal spine variable, less than, or considerably longer than, the head, base of 




Fig. 34. Plecostomus hemiurus Eigenmann. Type. C. M. Cat. No. 1544. 

dorsal equal to its distance from the caudal. Caudal oblique, emarginate, the 
lower rays usually less than twice the length of the middle rays; ventrals reaching 
middle of anal; pectorals to second third of ventrals or beyond. 

Dark brown, with dark olive spots, smallest on the head, absent on the belly; 
dorsal spotted along the basal half or near its tip ; caudal sometimes uniform dark 
brown, its upper lobe sometimes colored like the dorsal, as well as the upper surface 
of ventrals and pectorals. 

92. Plecostomus watwata (Hancock). (Plate XXVI, fig. 1.) 
Hypostomus watwata Hancock, Zool. Journ., IV, 1829, 245 (Georgetown). 
Hypostomus plecostomus (not of Linnaeus) Cuvier and Valenciennes, Hist. Nat. 

Poiss., XV, 1840, 489 (Maracaibo). 
Hypostomus verves Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 494 

(Cayenne). 



226 MEMOIRS OF THE CARNEGIE MUSEUM 

Plecostomus verrcs Regan, Trans. Zool. Soc. London, XVII, 1904, 209. 
Hypostomus commersonii (not of Cuvier and Valenciennes) Muller and Troschel, 

in Schomburgk, Reisen, III, 1848, 631 (Takutu). 
? Hypostomus pantherinus Kner, Denkschr. Akad. Wiss. Wien, VII, 1854, 267 

(Rio Guapore). 
Plecostomus bicirrhosus Gunther, Catalogue, V, 1864, 231, part. 

One specimen, 273 mm. Mahaica. (I. U. Cat. No. 11961.) 

Two specimens, 128-435 mm. Georgetown. (C. M. Cat. No. 1540.) 

There are also five specimens in the Amsterdam Museum, probably from 
Surinam. 

Head 3.25-3.5; depth 4.66-6; D. 1,7; A. 1,4; scutes 28. Eye 6-8 in the head; 
interorbital 2.25 in the head; mandibular ramus about 3 in the interorbital. 

Occipital with a well-marked median ridge, bordered behind by a median and 
several lateral plates; supraocular ridge continued on the upper part of the sides 
as a keel; all plates, except those on the caudal peduncle, keeled. 

Dorsal spine about equal to head or pectoral spine; base of dorsal equal to 
its distance from the tip of the spine of the adipose. 

Olive, everywhere with darker spots, smallest on the head and largest on the 
belly; fins banded in the young, spotted in the old. 

In the specimen at the Berlin Museum mentioned by Schomburgk as commer- 
sonii the occipital is bordered by a large median and one small lateral plate on each 
side. 

93. Plecostomus emarginatus Cuvier and Valenciennes. 

' ' Warra-warra " ; " Morutta " ; " Wacari . ' ' 

Hypostomus emarginatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

500 (Brazil).— Kner, Denkschr. Akad. Wiss. Wien, VII, 1854, 260 (Barra do 

Rio Negro). 
Plecostomus emarginatus Gunther, Catalogue, V, 1864, 233. — Eigenmann and 

Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 167; Occasional Papers Cal. 

Acad. Sci., I, 1890, 400 (Cudajas; Santarem; Manacapuru; Tonantins; Obidos; 

Fonteboa; Tabatinga; Hyavary; Sao Paulo; Goyaz) ; Proc. U. S. Nat. Mus., 

XIV, 1891, 40. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 406. 
Hypostomus squalinum S( homburgk, Fishes Brit. Guiana, I, 1841, 142, pi. 3 (Rio 

Branco; Rio Negro; Rio Essequibo), 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 227 

Hypostomus squalitus Muller and Troschel, in Schomburgk, Reisen, III, 1848, 

142 (Essequibo; Rio Branco; Takutu). 
Hypostomus horridus Kner, Denksehr. Akad. Wiss. Wien, VII, 1854, 259. 
Phcostomus horridus Gunther, Catalogue, V, 1864, 232. — Peters, MB. Akad. 

Wiss. Berlin, 1877, 471 (Calabozo). 
Phcostomus scopularius Cope, Proc. Acad. Nat. Sci. Phila,, 1871, 55, 286, pi. 16, 

figs. 1, 2 (Ambyiacu). 
Phcostomus biseriatus Cope, Proc. Acad. Nat. Sci. Phila., 1871, 285, pi. 16 (Ama- 
zon). — Eigenmann and Eigenmann, Occasional Papers Cal. Acad. Sci., I, 

1890, 409. 
? Phcostomus rircsccns ('<>pe, Proc. Acad. Nat. Sci. Phila., 1874, 137 (Upper 

Amazon); Proc. Am. Philos. Soc, XVII, 1878, 681 (Peruvian Amazon); 

XXXIII, 1894, 101. — Eigenmann and Eigenmann, Occasional Papers Cal. 

Acad. Sci., I, 1890, 408. 
Phcostomus villarsi Lutken, Overs. Kgl. Dan. Vidensk.-Selsk. Forh., 1874, 211 

(Caracas). — Steindachner, " Fisch-fauna Magdalenen-Stromes," 1878, 26, 

pi. 7. — Eigenmann and Eigenmann, Occasional Papers Cal. Acad. Sci., I, 

1890, 408. 
Phcostomus tenuicauda Steindachner, " Fisch-fauna Magdalenen-Stromes," 1878, 

24, pi. 6 (Magdalena); "Fisch-fauna des Cauca," etc., 1880, 11 (Cauca). 
Phcostomus annce Steindachner, Flussfische Slidamerika's," ii, 1881, 12, pi. 3, 

% 2. 

While no specimens were secured, it is not at all improbable that this species 
will be found in British Guiana. So far it has been recorded only by Schom- 
burgk, who may have seen the common species of the Essequibo, Phcostomus 
hemiurus. 

Head 3.33-4; depth 6-7; D. 1,7; A. 1,4. Scutes 28 to 30. Eye 5-11 in the 
head; interorbital 2.33-2.66; mandibular ramus 3-4 in the interorbital. Width of 
head 1.13-1.25 in its length, snout 1.75-1.85 times. Eight or nine plates between 
the dorsals, fourteen to fifteen behind the anal; dorsal spine as long as the head, the 
last ray half as long. Dark spots on the head, body, and fins, those on the dorsal 
usually arranged in two series between each pair of rays. 

Pterygoplichthys Gill. 
Pterygoplichthys Cill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 408 (duodecimalis). 
Liposarciis Gunther, Catalogue, V, 1864, 238 (sp.). 

Type, Hypostomus duodecimalis Cuvier and Valenciennes. 



228 MEMOIRS OF THE CARNEGIE MUSEUM 

94. Pterygoplichthys multiradiatus (Hancock). 
Hypostomus multiradiatus Hancock, Zool. Journ., IV, 1828, 226 (Demerara). 
Liposarcus multiradiatus Gunther, Catalogue, V, 1864, 238 (Demerara). 
Pterygoplichthys multiradiatus Eigenmann and Eigenmann, Occasional Papers Cal. 

Acad. Sci., I, 1890, 433; Proc. U. S. Nat. Mus., XIV, 1891, 42.— Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 408. 

The following description is by Gunther and is based on the type in the 
British Museum: 

"D. 1/13. A. 5. P. 1/6. V. 1/5. L. lat, 29. 

"Head not depressed, its length being two-sevenths of the total (without 
caudal); a rather prominent ridge runs from the eye to below the nostril; occiput 
with a rather elevated ridge, scutes of the nape bicarinate. Barbel longer than the 
eye, which is rather small, its diameter being nearly one-fourth of the width of the 
interorbital space. Interoperculum without any spines. Thorax and belly entirely 
granulated. Dorsal fin much longer than high, the length of its base being equal 
to its distance from the extremity of the snout; the length of its anterior rays 
equals that of the head; there are six scutes between the two dorsal fins. (Caudal 
fin injured.) Eleven scutes between anal and caudal. The pectoral spine does 
not extend on to the middle of the ventral. Scutes of the body with a serrated 
keel. Ferruginous grey." 

Lithogenes Eigenmann. 
Lithogenes Eigenmann, Ann. Carnegie Mus., VI, 1909, 6. 

With the characters of Plecostomus, but the dermal armature reduced to a 
few ossicles on the back behind the adipose and along a median line from above the 
origin of the anal to the caudal. 

95. Lithogenes villosus Eigenmann. (Plate XXVI, figs. 2-4.) 
Lithogenes villosus Eigenmann, Ann. Carnegie Mus., VI, 1909, 6. 

Type unique, 44 mm. Aruataima Falls, Upper Potaro. (Carnegie Museum 
Catalog of Fishes No. 1002.) 

Head 3.5; depth 7; D. 8; V. 1,4; P. 1,8; eye 6 in snout, 8 in head, 2.75 in 
interorbital; width of head equaling snout and orbit; width behind the pectorals 
about one-fifth greater than the height. 

Oral disk large, margined by a series of incisions; lips smooth, with the faintest 
rugosities; a bunch of about twenty-five blunt villi in immediate association with 
the dentary; barbel equal to prenasal part of the snout, measuring from the base 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 229 

of the barbel; free part of barbel equaling eye; a narrow free membrane from the 
barbel margining the lip outside of the incised inner margin from the barbel to a 
point behind the angle of the mouth. 

Dentary with two teeth, each with two widely diverging cusps; premaxillary 
with eight teeth, each with two nearly parallel cusps, of which the inner one is 
much the longer. 

Origin of the dorsal above the middle of the ventrals, the first ray not much 
more than half as long as the second, not spinous, the highest ray a little less than 
the snout; spine of the adipose two-fifths of the length of the snout, covered with a 
few spinules, its tip nearly reaching end of base of adipose part of the fin; caudal 
rather deeply emarginate, the lower lobe the longer; origin of anal half-way between 
tip of dorsal and origin of adipose; outer ventral ray very thick and fleshy, covered 
with spines, its base much wider than that of the rest of the fin, reaching a little 
more than half-way to anal, its length equal to the snout; pectoral reaching to near 
tip of ventrals, its spine not much larger than the rest of the rays, with a few prickles. 

Naked except for a double series of plates along the ventral surface of the 
caudal peduncle from near the tip of the anal, which curve up on either side of the 
caudal to the base of the middle rays; about fourteen platelets along the middle of 
the sides from above the origin of the anal to the base of the middle caudal rays, 
widest above the tip of the anal, where they are a little wider than the eye; a double 
series of plates on the back, beginning on either side of the spine of the adipose 
to the caudal; outer caudal rays with prickles, a few spinelets on the caudal. 

A dark band from the eye forward, increasing in width to above the base of 
the maxillary; back and upper part of sides marbled; caudal dark, the outer rays 
lighter. 

For comparison I have added a figure of the Neoplecostomus granosus (Plate 

XXVI, fig. 5). 

Corymbophanes Eigenmann. 

Corymbophanes Eigenmann, Ann. Carnegie Mus., VI, 1909, 5. 

Type, Corymbophanes andersoni Eigenmann. 

Allied to Rhinelepis. No adipose fin, this being replaced by a low median 
ridge, extending from the tip of the dorsal to the caudal; no externally visible 
occipital crest. 

96. Corymbophanes andersoni Eigenmann. (Plate XXVII, figs. 1-3.) 
Corymbophanes andersoni Eigenmann, Ann. Carnegie Mus., VI, 1909, 5. 

Type unique, 86 mm. Aruataima Falls, Upper Potaro. (Carnegie Museum 
Catalog of Fishes No. 1001.) 



230 MEMOIRS OF THE CARNEGIE MUSEUM 

Head 3.66 in the length, measured to end of opercle and end of the lateral 
plates; depth 6; D. 1,7; A. 1,4; V. 1,5; P. 1,6; lateral line 24; eye 5.5 in snout, 7.5 
in head to end of opercle, 3 in interorbital. 

Oral disk everywhere thickly papillose, the papillae largest along the margin of 
the upper lip and smallest at the angle of the mouth; barbel about 2.5 in the snout, 
its free portion less than orbit in length, its ventral surface papillose; maxillary 
and dentary of about equal length, a little less than 1.5 in the interorbital, each 
jaw with numerous minute teeth. 

Ventral surface entirely naked; margin of snout in front of base of barbels 
naked; predorsal scales not regular; posterior margin of skull concave on each side 
of the occipital crest, which is indicated by a point; no ridges or grooves about the 
head; lateral plates straight, not keeled; a rather broad naked area along the dorsal. 

Origin of dorsal in front of the vertical from the ventrals; ventrals a little in 
advance of the middle; highest dorsal ray reaching to about the middle of the last 
ray, 4.5 in the length; caudal emarginate, the lower lobe slightly the longer; origin 
of anal under vertical from middle of last dorsal ray; ventrals reaching middle of 
anal, pectorals past origin of ventrals. 

Dark, with faint lighter spots; fin-rays dark, the membranes hyaline. 

This species, obtained at my farthest point, is named for Mr. C. Wilgress 
Anderson, Government Surveyor, an explorer in the Potaro and Roraima regions. 

Hemiancistrus Bleeker. 
Hemiancistrus Bleeker, Nederl. Tijdschr. Dierk., 1,1863,78 (medians) . — Eigen- 

mann and Eigenmann, Occasional Papers Cal. Acad. Sci., I, 1890, 417. 

Type, Ancistrus medians Kner. 

Teeth small; snout granular to its margin, without bristles; interopercle with 
spines; an adipose fin. 

A genus of about a dozen species, ranging from the Pacific slope of Panama to 
eastern Peru and Paraguay. 

Three species seem to occur in British Guiana, although only one was actually 
secured. They may be distinguished as follows: 

Key to the Guiana Species of Hemiancistrus. 
a. Interorbital 2.66 in the head; depth S in the length; head 2.6 times as long as deep; mandibular 

ramus 2.33 in interorbital schomburgki. 

an. Interorbital 3.5 in the head; depth 4-4.5 in the length; head 1.66-1.75 times as long as deep; man- 
dibular ramus l.S in the interorbital; lower surface naked megacephalus. 

aaa. Interorbital 2 in the head; depth 4.75 in the length; mandibular ramus 2 in the interorbital; 
occipital bluntly keeled; lower surface partly covered braueri. 



eigenmann: the freshwater fishes of British guiana 231 

97. Hemiancistrus schomburgki ( Hinther. 
Chcetostomus schomburgkii Gtjnther, Catalogue, V, 1804, 245 (British Guiana). 
Hemiancistrus schomburgkii Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 

II, 1889, 43; Occasional Papers Cal. Acad. Sci., I, 1890, 420. — Kindle, Ann. 

N. Y. Acad. Sci., VIII, 1895, 254. 
Ancistrus schomburgkii Regan, Trans. Zool. Soc. London, XVII, 1904, 233 (Guiana). 
—Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 408. 

No specimens were secured. 

"Depth of body 8 times in the total length, length of head 3 times. Head 
nearly as broad as long and 2f times as long as deep. Diameter of eye 4f-5f 
times in the length of head, interorbital width 2f times, length of snout 1^ times. 
Length of mandibular ramus 2^ times in the interorbital width. Snout broad, 
rounded; supraorbital edges not raised; supraoccipital flat, without median ridge; 
temporal plates not carinate; interoperculum armed with 20-25 slender spines with 
curved tips, the longest equal to twice the diameter of eye. Scutes spinulose, not 
carinate, 25 in a longitudinal series, 6 between dorsal and adipose fin, 11-12 be- 
tween anal and caudal. Supraoccipital bordered posteriorly by a median scute 
and by one on each side. Lower surface of head and abdomen naked (in the young) . 
D. 1,7, the first ray f the length of head; length of base of dorsal nearly equal to 
its distance from the adipose fin. A. 1,4. Pectoral spine not reaching the base 
of ventral. Caudal peduncle 3 times as long as deep. Brownish, clouded with 
darker; dark spots on the fins. 

"Total length 75 mm." — Regan. 

98. Hemiancistrus megacephalus Giinther. 

Chcetostomus megacephalus Gunther, Proc. Zool. Soc. London, 1868, 232 (Suri- 
nam ?). 

Hemiancistrus megacephalus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., 
(2), II, 1889, 44; Occasional Papers Cal. Acad. Sci., I, 1890, 420; Proc. U. S. 
Nat. Mus., XIV, 1891, 41.— Kindle, Ann. N. Y. Acad. Sci., VIII, 1895, 253.- 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 408. 

Ancistrus megacephalus Regan, Trans. Zool. Soc. London, XVII, 1904, 234 
(Guiana). 

Chcetostomus macrops Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 209 
(Surinam). — Steindachner, " Flussfische Sudamerika's," ii, 1881, 24, pi. 5, 

fig. 3. 

Nine specimens, 86-185 mm. Amatuk. (C. M. Cat. No. 1536^-6; I. U. Cat. 
No. 11958.) 



232 MEMOIRS OF THE CARNEGIE MUSEUM 

One specimen, 107 mm. Warraputa. (C. M. Cat, No. 1537a.) 

Five specimens, 25-94 mm. Waratuk. (C. M. Cat. No. 1538o-6; I. U. Cat. 
No. 11959.) 

Head 2.8-3; depth 4.5-5.2; D. 1,7; A. 1,4; scutes twenty-four or twenty-five, 
counting the one on the caudal ; four pairs of scutes between the dorsals, nine to 
eleven plates behind the anal. 

Eye 5-5.5; interorbital 3.5-3.75; mandibular ramus 1.4-1.6 in interorbital; 
opercle with bristles, curved at their tips, entirely retractile under the opercle, the 
longest in the adult male a little longer than the eye; margin of snout granular, the 
granules becoming bristle-like in adult males. Lower surface naked; supraorbital 
slightly raised in smaller specimens, head and body otherwise without keels; scutes 
with numerous spiniferous lines; occipital pointed, bordered by a notched median 
and two lateral plates. 

Dorsal spine slightly less than head in length; base of dorsal at least equal to 
its distance from the caudal; ventrals reaching middle of anal; pectoral spine to 
near middle of ventral or beyond; caudal oblique, emarginate. 

Dark; obscure whitish spots on upper surface; dorsal membrane nearly uni- 
form, the rays alternately light and dark; caudal with vertical bands, increasing 
in number with age; upper surface of pectoral and ventral with spots or bars. 

99. Hemiancistrus braueri sp. nov. (Plate XXVIII, figs. 1-2.) 
Hypostomus itacua (not of Cuvier and Valenciennes), Muller and Troschel, in 

Schomburgk, Reisen, III, 1848, 631 (Takutu). 

Two specimens, 110-120 mm. Guiana (Schomburgk). Berlin Museum 
No. 3174. The larger one is the type. 

Head 2.8; depth at occiput 4.75; D. 1,8; A. 1,4; plates twenty-seven, count- 
ing the one on the caudal; five plates between the dorsal fin and the adipose 
fulcrum; fourteen plates behind the anal, counting all the fulcra; eye 5 in the 
head, interorbital 3; mandibular ramus 2 in the interorbital. 

Head rather deep; none of the scales carinate; supraorbitals elevate, a distinct- 
median keel on the occipital which is superficially divided into a number of fields; 
temporal plates not carinate; interopercle armed with about forty slender spines 
with curved tips, the spines completely revertible, the longest not quite one and 
one-half times as long as the eye; lower surface of head naked; abdomen with 
a small patch of plates between the last ventral rays, and a large patch from be- 
tween the gill-openings to the middle of the pectoral, the rest of the abdomen 
naked in the type, with minute prickles and a few plates along the middle in the 
cotype. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 233 

Dorsal spine an orbital diameter less than the length of the head; last dorsal 
ray attached by an insignificant membrane only; pectoral spine reaching second 
third of the ventral; ventral to the base of the last anal ray. 

Fins uniformly dusky; sides and back obscurely blotched or banded. 

The adipose is lacking in the cotype. 

Pseudancistrus Bleeker. 

Pseudancistrus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 78 (barbatus). — Eigen- 
mann and Eigenmann, Occasional Papers Cal. Acad. Sci., I, 1890, 434. 
Type, Hypostomus barbatus Cuvier and Valenciennes. 
Similar to Hemiancistrus, but the sides of the head with bristles, which are 

much larger in the male; interopercle with bristles; an adipose dorsal. 
A genus with four or five species, of which three are found in Guiana. 

Key to the Guiana Species op Pseudancistrus. 

a. Length of base of dorsal equal to its distance from the caudal. 

b. Slate-color, with numerous white dots; depth 5.66-6; eye 5 in the head barbatus. 

bb. Uniform slate-color; depth 4.5-5; eye 6.5 in the head nigrescens. 

aa. Length of base of dorsal nearly equal to its distance from the adipose giintheri. 

100. Pseudancistrus barbatus (Cuvier and Valenciennes). (Plate XXVIII, fig. 3.) 

Hypostomus barbatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 506 
(La Mana).— Schomburgk, Fishes Brit. Guiana, I, 1841, 147.— Kner, 
Denkschr. Akad. Wiss. Wien, VII, 1853, 268, pi. 2, fig. 2 (locality ?). 

Plecostomus barbatus Gunther, Catalogue, V, 1864, 237 (Surinam). 

Pseudancistrus barbatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 

II, 1889, 45; Occasional Papers Cal. Acad. Sci., I, 1890, 435; Proc. U. S. Nat. 
Mus., XIV, 1891, 1842.— Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 409. 

Ancistrus barbatus Regan, Trans. Zool. Soc. London, XVII, 1904, 240. 
Hypostomus guttatus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 508 

(Surinam) . 
Plecostomus guttatus Gunther, Catalogue, V, 1864, 237 (British Guiana). 
Pseudancistrus guttatus Bleeker, " Silures de Suriname," 1864, 10, pi. 2, fig. 2, 

pi. 3, fig. 3 (Surinam). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., 

(2), II, 1889, 45; Occasional Papers Cal. Acad. Sci., I, 1890, 435; Proc. U. S. 

Nat. Mus., XIV, 1891, 42. 

Two specimens, 121-140 mm. Crab Falls. (C. M. Cat. No. 1533; I. U. Cat. 
No. 11968.) 



234 



MEMOIRS OF THE CARNEGIE MUSEUM 



Six specimens, 60-116 mm. Warraputa. (C. M. Cat. Xo. 1534a-&; I. U. 
Cat. No. 11956.) 

Four specimens, 80-143 mm. Rockstone. (C. M. ( at. No. 1535a-&; I. U. Cat. 
No. 11957.) 

Head 3; depth 5.66-6 to end of middle caudal plate; D. 1,7; A. 1,5. Twenty- 
five scutes, counting the one on the caudal; four pairs and an azygous plate be- 
tween the dorsals; eleven plates behind the anal. 

Width of head equal to its length or very little narrower; eye 5 in head, inter- 
orbital not quite 4; mandibular ramus but little less than interorbital; opercle in 
the male (C. M. Cat. No. 1533) with a bunch of graduate bristles, the longest 2.66 
in the head, not completely retractile and not hooked; marginal bristle in the 
same male three-fourths the length of eye. Bristles scarcely evident in female. 
Head and plates without keels; belly entirely naked; dorsal spine equal to snout 
and eye or half eye. Base of dorsal equal to its distance from the caudal, last ray 
scarcely adnate. Caudal obliquely emarginate; ventrals reaching past origin of 
anal; pectorals past origin (to second third) of ventrals. 

All but the ventral surface brown or slaty, with clear white dots. 

The alimentary canal in a specimen 100 mm. long is 855 mm. in length. 



101. Pseudancistrus nigrescens sp. nov. (Plate XXV, fig. 2.) 
Pseudancistrus nigrescens Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III. 
1910. 409 (name only . 




Fig. 35. Pseudancistrus nigrescens Eigenmann. Type. C. M. Cat. No. 1539. 

Type, 182 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. i539.) 
Cotype, 149 mm. Amatuk. (I. U. Cat. No. 11960). 



eigknmann: the FRESHWATER FISHES OF BRITISH GUIANA 235 

Head about 3; depth 4.5-5; D. 1,7; A. 1,4; plates twenty-four; three or four 
paired plates between the dorsal, eleven behind the anal; width of head almost 
equal to its length; interprbital 3.5 in the head, eye 6.5; mandibular ramus 1.4 
in the interorbital. 

Head convex, without ridges or crest; plates of the body not carinate; oc- 
cipital truncate where it meets the median plate behind it; interopercle with a few 
bristles; snout with a swollen margin, sparingly provided with bristles. 

Dorsal spine a little longer than eye and snout; base of dorsal slightly less than 
its distance from the caudal; caudal oblique, slightly emarginate; ventrals reach- 
ing to middle of anal; pectorals about to second third of ventrals. 

Nearly uniform dark slaty; dorsal with very faint light areas along the rays. 
Distal part of caudal slightly lighter, otherwise uniform; pectorals and ventrals 
in the smaller specimens like the caudal, very faintly blotched in the larger. 

102. Pseudancistrus guentheri Regan. 
Plecostomus guttatus (not of Cuvier and Valenciennes) Gunther, Catalogue, V, 

1864, 237. 
Ancistrus guentheri Regan, Trans. Zool. Soc. London, XVII, 1904, 241 (British 

Guiana) . 
Pseudancistrus giinthcri Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 409. 

Xo specimens were collected. It is not certain whether the above references 
pertain to the area covered by this paper or not. 

Head 3.25; depth 6; D. 1,7; A. 1,4; depth of head 2 in its length, eye 8, inter- 
orbital 3.33; mandibular ramus 1.25 in interorbital; snout with a broad naked 
area at its tip; dorsal spine two-thirds the length of the head; pectoral spine not 
quite reaching base of ventral. Color uniform. 

Xenocara Regan. 
Xenocara Regan, Trans. Zool. Soc. London, XVII, 1904, 251.— Eigenmann, 

Science, n. s., XXI, 1905, 794. 

Type, Ancistrus gymnorhynchus Kner. 

Interopercle freely movable, usually with spines; snout with a naked margin 
and without tentacles; mouth narrow, the mandible much less than the width 
of the interorbital; teeth in the upper jaw about as numerous as those in the lower 



236 MEMOIRS OF THE CARNEGIE MUSEUM 

103. Xenocara gymnorhynchus (Kner). 
? Hypostomus nudiceps Muller and Troschel, in Schomburgk, Reisen, III, 

1848, 631 (Takutu). 24 
? Chatostomus nudiceps Gunther, Catalogue, V, 1864, 249 (copied). — Eigenmann 

and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 46; Occasional Papers 

Cal. Acad. Sci., I, 1890, 443; Proc. U. S. Nat, Mus., XIV, 1891, 43. 
? Ancistrus gymnorhynchus Kner, Denkschr. Akad. Wiss. Wien, VII, 1854, 275 

(Puerto Cabello). 
Cha'tostomus gymnorhynchus Gunther, Catalogue, V, 1864, 249 (Puerto Cabello). 

— Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 204. — Eigenmann 

and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 46; Occasional Papers 

Cal. Acad. Sci., I, 1890, 444; Proc. U. S. Nat. Mus., XIV, 1891, 43.— Regan, 

Trans. Zool. Soc. London, 1904, 254. 
Xenocara gymnorhynchus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 410. 

One specimen, 58 mm. Gluck Island. (C. M. Cat. No. 1526.) 

Head 3; depth at tip of occipital 6.5; interorbital 3.6 in the head; eye 5 in the 
head; width of head an orbital diameter less than its length; mandibular ramus 
2 in interorbital. D. 1,7; A. 1,4. No tentacles on the snout; the naked area 
narrow, one-sixth the distance from tip of snout to posterior margin of eye along 
the median line. Six plates between the dorsals, ten behind the anal, twenty- 
five along the sides. 

Last dorsal ray not quite reaching the adipose, base of dorsal nearly equal 
to its distance from tip of spine of the adipose fin; dorsal spine equal to snout and 
orbit. 

Caudal sinuate, distinctly oblique, but the lower lobe a little longer than the 
upper, equal to the length of the head. 

Blackish, with yellowish white, faintly ocellated spots; pectoral and ventrals 
with faint spots; dorsal and caudal narrowly margined with reddish. 

24 1 have been able to examine the type of nudiceps in the Berlin Museum, 10.5 mm., No. 3180, 
Guiana. Schomburgk. 

Head 2+; depth at occipital process 6+; interorbital 2.4 in the head; eye 5.5 in the head; width of 
the head an orbital diameter less than its length; mandibular ramus 3.4 in the interorbital; D. 1,7; A. 
1,4; no tentacles about the snout; naked area at least one-third the distance from tip of snout to pos- 
terior margin of the eye along the median line; five plates between the last dorsal ray and the spine of 
the adipose, nine behind the anal, twenty-two along the sides. Pectoral reaching to the second fourth 
of the ventral; ventral beyond the base of the last anal ray. In other distinguishable characters it is like 
the specimen from Gluck Island. 



EIGENMANN : THE FRESHWATER FISHES OF BRITISH GUIANA 237 

Ancistrus Kner. 
Ancistrus Kner, Denkschr. Akad. Wiss. Wien, VII, 1853, 272 (sp.). — Bleeker, 

Nederl. Tijdschr. Dierk., I, 1863, 77 (cirrhosiis) . 
Tlnjxanocara Regan, Ann. and Mag. Nat. Hist., (7), XVII, 1906, 95 (cirrhosus). 

Type, Ancistrus cirrhosus Kner. 

I have elsewhere (Science, n. s., XXI, 1905, 794) given my reasons for the 
use of the name Ancistrus for this genus. 

Premaxillaries and dentaries of nearly equal length; interopercle movable; 
snout naked, with tentacles. About eleven species. 

Key to the Guiana Species of Ancistrus. 25 
a. Fins, especially the dorsal, with conspicuous cross-bands over rays and membranes; body with large 
whitish spots, the dark background reduced to vermiculations; ramus of the lower jaw 2.3-3 

in the interorbital temmincki. 

aa. Fins, especially the dorsal, with faint dark spots along the rays; mandibular ramus 2-3 in inter- 
orbital; interorbital 2.4 in the head; depth about equal to interorbital; naked portion of snout 
of the male reaching nearlj r half-way to posterior margin of the eye, with a Y-shaped series of 

tentacles; obscure, medium-sized light spots, especially on the ventral surface cirrhosus. 

uaa. Fins, especially the dorsal, plain, or frequently with minute white dots, the dorsal and caudal often 

margined with lighter. 

6. Mandibular ramus 2.75-3.75 in the interorbital; interorbital 2.25 in the head; dorsal and upper 

angle of caudal narrowly margined with light, or not margined; naked part of snout in the 

male with about four tentacles in a straight line; naked part extending one-fourth the distance 

to posterior margin of eye along median line. Minute white dots on fins and body. 

hoplogenys. 
bb. Mandibular ramus 2.0-2.4 in the interorbital; dorsal and caudal conspicuously margined with 
white or yellow. Naked portion of snout, in adult male, reaching half-way to posterior 
margin of eye, in the female one-third the distance to posterior margin of eye. Inter- 
orbital 2.8-3 in head; depth 6.8 in the length. Tentacles in male in a Y-shaped figure. 
Occipital finely granular, the granules scarcely arranged in radiating lines; base of dorsal 
equal to the distance from base of last ray to tip of spine; caudal very oblique, the upper 
lobe about 14 the length of the lower; minute white dots on fins and body, otherwise 
plain black , lithurgicus. 

104. Ancistrus temmincki (Cuvier and Valenciennes). 
Hypostomus temminckii Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

514 (Cayenne). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 

631 (Takutu). 
Ancistrus temminckii Bleeker, " Silures de Suriname," 1864, 11, pi. 1, fig. 3, pi. 2, 

fig. 2 (Surinam). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 

25 Regan gives Ancistrus dolichoptera Kner as found in Guiana. No definite locality is given. 
If it should be found within the region covered by the present paper it can readily lie distinguished by 
its having D. 1,8 or 9. 



238 MEMOIRS OF THE CARNEGIE MUSEUM 

1891, 43. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 411. 
Xenocaru temminckii Regan, Trans. Zool. Soc. London, XVII, 1904, 254 (Guiana). 

Two specimens, 74 and 56 mm. Packeoo Falls. (C. M. Cat. No. 1520a; 
I. U. Cat, No. 11946.) 

Two specimens, 47 and 38 mm. Rupununi Pan. (C. M. Cat. No. 1521a; 
I. U. Cat. No. 11947.) 

Two specimens, 43 and 52 mm. Chipoo Creek, a branch of the Ireng near 
Karakara. (C. M. Cat. No. 1522; I. U. Cat. No. 11948.) 

Head 3 or a little less, depth at tip of occipital 5.5 in the length; width of head 
about an orbital diameter less than its length; interorbital about 2.5 in the length 
of the head; mandibular ramus 2.33-3 in the interorbital; D. 6; A. 1,4; eye 5.5 in 
the head (in the largest specimen). About ten interopercular spines; naked part of 
the snout (in the largest specimen) extending one-fourth the distance to posterior 
margin of eye along the median line; three pairs of plates between the occiput and 
the dorsal, five plates between the dorsals, ten between the last anal ray and 
the caudal, and twenty-three along the sides. 

Head finely granular, granules of posterior part of occipital arranged in faint 
radiating rows; plates of the sides with series of spines; last dorsal ray extending 
to the spine of the adipose; length of base of dorsal equal to its distance from the 
middle of the spine of the adipose dorsal; dorsal spine an orbital diameter or less 
shorter than the head; lower caudal rays equal to length of head. Ventrals 
rounded, reaching to middle of anal; pectoral to third fifth of ventrals. 

General effect dark. Numerous light spots about as large as the pupil, 
smaller below, the spots of the back sometimes confluent, in rows. Dorsal with 
three to five wavy cross-bands; caudal spotted with dark, other fins with cross- 
spots. Dorsal and caudal sometimes margined with light. 

The color of the specimens in the Leiden Museum is uniformly dark. The same 
is true of the specimen in Berlin collected by Schomburgk in Guiana. As the latter 
is in rather bad condition I am not prepared to say whether it belongs to the 
present species or the next. 

105. Ancistrus cirrhosus (Cuvier and Valenciennes). 
Hy postomus cirrhosus Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 511 

(Rio Janeiro; Buenos Ayres). — Valenciennes, in d'Orbigny, Voy. Am. Mer., 

V, ii, 1847, pi. 7, fig. 3. 
Ancistrus cirrhosus Kner, Denkschr. Akad. Wiss. Wien, VII, 1854, 272 (Rio Gua- 

pore). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 239 

48; Occasional Papers Cal. Acad. Sci., I, 1890, 446 (Cudajas; Obidos); Proc. 

U. S. Nat. Mus., XIV, 1891, 43.— Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 411. 
Chcetostomus cirrhosus Gunther, Catalogue, V, 1864, 247 (Essequibo, British 

Guiana). — Hensel, Archiv fur Xaturg., I, 1870, 76 (stony mountain streams). 
-Vaillant, Bull. Soc. Philom., (7), IV, 1880, 155 (Calderon).— Steix- 

dachner, " Flussfische Siidamerika's," iv, 1882, 7 (Rio Huallaga). — Perugia, 

Ann. .Mus. Genova, (2). XVIII, 1897, 21 (Rio Beni). 
Xrnocara cirrhosa Regan, Trans. Zool. Soc. London, XVII, 1904, 256 (Rio Para- 
guay; Amazon; Guiana; Trinidad). 
Chcetostomus variolus Cope, Proc. Acad. Xat. Sci. Phila., 1871, 288 ( Ambyiacu).— 

Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 64; Occa- 
sional Papers Cal. Acad. Sci., I, 1890, 442. 

Three specimens, 48 to about 100 mm. Ireng River near Holmia. (C. M. 
Cat. Xo. 1523; I. U. Cat. No. 11949.) 

Head 2.85-3; depth at tip of occipital 2.4 in the head; width of head an orbital 
diameter less than its length; interorbital 2.4 in the head; mandibular ramus 2-3 
in the interorbital; D. 1,7; A. 1,4; eye 5.5 in the head in the largest specimen; 
about twelve interopercular spines, the longest 4.5 in the head. 

Tentacles numerous, the naked area reaching half-way to the posterior margin 
of the eye in the largest specimen, which is a male; six plates between the dorsals, 
ten between the anal and caudal, and twenty-four along the sides. 

Last dorsal ray scarcely reaching the spine of the adipose; base of dorsal a 
little greater than its distance from the adipose; dorsal spine equal to snout and 
eye; ventrals about reaching middle of anal; pectoral spine reaching third fifth 
of ventrals. 

Black, with faint white spots; dorsal and caudal with dark spots along the 
rays; pectorals and ventrals spotted or plain. 

106. Ancistrus hoplogenys (Gunther). 
Chcetostomus hoplogenys Gunther, Catalogue, V, 1864, 247 (River Capin, Para). 
Ancistrus hoplogenys Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 

1889, 48; Occasional Papers Cal. Acad. Sci., I, 1890, 448 (Tajapuru); Proc. 

U. S. Xat. Mus., XIV. 1891, 43.— Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 411. 
Xenocam hoplogenys Regan, Trans. Zool. Soc. London, XVII, 1904, 255 (Guiana; 

Amazon; Rio Paraguay ). 



240 MEMOIRS OF THE CARNEGIE MUSEUM 

Chcetostomus leucostictus Gunther, Catalogue, V, 1864, 248 (Essequibo). — Stein- 

dachner. "Flussfische Siidamerika's," iv, 1882, 7 (Rio Huallaga). 
Ancistrus leucostictus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., I, 1890, 

447 (Coary; Tabatinga; Jutahy); Proc. U. S. Nat. Mus., XIV, 1891, 43. 
Chcetostomus alga Cope, Proc. Acad. Nat. Sci. Phila., 1871, 287, pi. 15, fig. 3 (Am- 

byiacu). 
Chcetostomus malacops Cope, Proc. Acad. Nat. Sci. Phila., 1871, 287, pi. 5, fig. 2 

(Ambyiacu). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II. 

1889, 46; Occasional Papers Cal. Acad. Sci., I, 1890, 443; Proc. U. S. Nat. 

Mus., XIV, 1891, 43. 
Chcetostomus tectirostris Cope, Proc. Acad. Nat. Sci. Phila., 1871, 288, pi. 15, fig. 2 

(Ambyiacu). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II. 

1889, 46; Occasional Papers Cal. Acad. Sci., I, 1890, 442; Proc. U. S. Nat. 

Mus., XIV, 1891, 43. 

One specimen, 63 mm. Gluck Island. (C. M. Cat, No. 1517.) 

Nine specimens, 50-108 mm. Packeoo Falls, Essequibo. (C. M. Cat. No. 
1518a-c; I. U. Cat. No. 11944.) 

Eighteen specimens, 63-119 mm. Rupununi Pan. (C. M. Cat. No. 1519a-d; 
I. U. Cat. No. 11945.) 

Head 2.8; depth at tip of occipital 5-5.2 in the length; width of head an 
orbital diameter or less than an orbital diameter smaller than its length; interorbital 
2.25 in the length of the head; mandibular ramus 2.75-3.75 in the interorbital; 
D. 1,7; A. 1,4; eye 5-6 in the head. About nine interopercular spines, hooked at 
the tip, the longest in the largest specimen 2.66 in the interorbital. 

Tentacles rather small, the naked area in the largest male with four bifid 
tentacles; naked area extending one-fourth the distance to the posterior margin 
of the eye; seven plates between the dorsals, eleven between the anal fin and the 
caudal plates, and twenty-five along the sides. Last dorsal ray reaching to, or 
beyond, origin of spine of the adipose; base of the dorsal equal to the distance 
from the base of the last ray to the tip of the spine of the adipose; dorsal spine 
equal to snout and orbit; lower caudal ray much longer than the upper, equal 
to the length of the head. Ventrals rounded, reaching the middle of the anal; 
pectoral spine reaching the third fifth of the ventrals. 

Black, with a few minute white spots everywhere; dorsal and caudal scarcely 
or not margined with lighter. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



241 



107. Ancistrus lithurgicus sp. now'-' 6 (Plate XXV, fig. 3.) 
Ancistrus lithurgicus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 411 (name only). 

Type, 95 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1524.) 

Cotypes, fifteen specimens, 31-88 mm. Crab Falls. (C. M. Cat. No. 1525a-d; 
I. U. Cat. No. 11950.) 

Head 2.8; much depressed; depth at tip of occipital process 6.8 in the length; 
width of head an orbital diameter less than its length; interorbital 2.8-3 in the 




Pig. 36. Ancistrus lithurgicus Eigenmann. Type. C. M. Cat. No. 1524. 



head; mandibular ramus 2-2.4 in the interorbital; D. 1,7; A. 1,4; eye 6 in the 
head in the largest specimen. Ten to twelve spines on the opercle, the longest 1.6 
in the interorbital. 

Tentacles profuse, the naked area of the snout in the male reaching half-way 
to the posterior margin of the eye; five or six plates between the dorsals, eleven 
behind the anal, and twenty-three or twenty-four along the sides. 

Last dorsal ray reaching adipose; base of dorsal about equal to its distance 
from the tip of the adipose; dorsal spine equal to snout and orbit; lower dorsal 
ray an orbital diameter less than the head. 

Black; a few minute white dots on back and fins, more numerous on belly, 
sometimes quite obscure; all fins black, the dorsal and caudal margined with white 
or yellow. 

Allied to A. hoplogenys, but much more depressed. 

26 Acanthicus, another genus of this subfamily, is represented in the Rio Branco basin of Guiana by 
Acanthicus hystrix Spix. 



242 MEMOIRS OF THE CARNEGIE MUSEUM 

Lithoxus gen. nov. 
Lithoxus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 412 (name 

only). 

Very much depressed, broad; lower surface flat, naked; preopercle with a 
bunch of spines, curved at the tip, the longest about equal to the orbit; snout more 
or less flexible, but covered with granular plates to its margin; premaxillaries not 
united, very short, with about two or three teeth on each side; mandibular ramus 
much wider, with seven to ten teeth on each side; pectorals in the male prolonged 
and densely covered with flexible spines along outer margin. Alimentary canal 
a little more than twice the total length. 

Allied to Pseudacanthicus, the species small, 27 much depressed. 

108. Lithoxus lithoides sp. nov. (Plate XXIX, figs. 1-4.) 
Lithoxus lithoides Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

412 (name only). 

Type, a male, 86 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 
1527.) 

Cotypes, eighty-six specimens, 25-85 mm. Amatuk. (C. M. Cat. No. 1528a-j; 
I. U. Cat. No. 11951.) 

Seventy-two specimens, 25-61 mm. Warraputa. (C. M. Cat. No. 1529a-,/; 
I. U. Cat. No. 11952.) 

Seven specimens, 30-57 mm. Konawaruk. (C. M. Cat. No. 1530a-6; I. U. 
Cat. No. 11953.) 

Thirteen specimens, 18-52 mm. Crab Falls. (C. M. Cat. No. 1531a-c; I. U. 
Cat, No. 11954.) 

Three specimens, 43 mm. Waratuk. (C. M. Cat. No. 1532a; I. U. Cat. No. 
11955.) 

Head 3.2; depth 10; D. 1,7; A. 1,3 or 1,4; V. 1,5; P. 1,6; width of head an 
orbital diameter less than its length; interorbital 3.5-4 in the head; eye 3-3.5 in 
snout, 6-6.5 in the head; mandibular ramus 2.5 in interorbital; five plates between 
the dorsals, ten behind the anal, twenty-three along the sides. 

Head without keels; occipital bordered by three plates behind; two or three 
plates between the occipital and a small V-shaped plate in front of the dorsal; 
plates of the body without keels. A circular oral disk, largely covered with warts. 
Caudal peduncle flat below. A groove between the dorsals. Entire region in front 
of the anal naked. Origin of dorsal about equidistant from the snout and the tip 
27 A female 63 mm. long contains eggs about 2 mm. in diameter, 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 243 

of the spine of the adipose; adipose fin long, the membrane extending to near the 
caudal; caudal obliquely truncate, the lower lobe much the longer, equal to snout 
and orbit or longer; anal minute; ventrals rounded, reaching middle of anal or a 
little farther; pectorals reaching to second third of ventral spine in the female, to 
near its tip in the male. 

Mottled, either sand-color or quite black. All the fins more or less barred. 

Abundant, clinging to the rocks in the rapids. Secured with " Hiari," which 
caused them to come to the surface. 

Subfamily Loricariin^e. 

Loricaria Linnaeus. 
Loricaria Linnaeus, Systema Naturae, ed. 10, I, 1758, 307. — Bleeker, Nederl. 

Tijdschr. Dierk., I, 1863, 80 (dura). 
Pseudohemiodon Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 81 (platycephalus) . 

Type, Loricaria dura Linnaeus = Loricaria cataphracta Linnaeus. 

Readily distinguished from the other Loricariids by its tentacled lips. 

109. Loricaria cataphracta Linnaeus. 

Loricaria dura {ex Linnaeus, Mus. Adolphi Fred., 1754, 79, pi. 29, figs. 1 and 2) 
Bleeker, "Silures de Suriname," 1864, 18 (Surinam). 

Loricaria cataphracta Linnaeus, Systema Naturae, ed. 10, I, 1758, 307; ed. 12, I, 
1766, 508 (America).— Bloch, Ausl. Fische, VIII, 1795, 76, pi. 75, figs. 3, 4.- 
Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 459 (Surinam, 
Cayenne). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 631 
(Rupununi). — Kner, Denkschr. Akad. Wiss. Wien, VI, 1853, 77 (Cujaba, 
Guapore). — Gunther, Catalogue, V, 1864, 255 (Surinam). — Peters, MB. 
Akad. Wiss. Berlin, 1877, 471 (Calabozo).— Cope, Proc. Am. Philos. Soc, XVII, 
1878, 681 (Maranon, Peru). — Eigenmann and Eigenmann, Proc. Cal. Acad. 
Sci., (2), II, 1889, 36 (Vigia; Sao Goncallo; Cameta; Manaos; Para; Rio Negro; 
Coary; Villa Bella; Gurupa; Rio Preto; Tajapuru; Porto do Moz; Teffe, 
Maranon; Ucayale; Obidos). — Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 
158 (Apure),405 (Manaos). — Eigenmann and Bean, Proc. U. S. Nat. Mus., 
XXXI, 1907, 665 (Amazon). — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 415. 

Loricaria cirrhosa Bloch and Schneider, Syst. Ichth., 1801, 125, pi. 34. 

Loricaria setifera Lacepede, Hist. Nat. Poiss., V, 1803, 140 (South America). 

Plecostomus flagellaris Gronow, Cat. Fish, ed. Gray, 1854, 158. 



244 MEMOIRS OF THE CARNEGIE MUSEUM 

Loricaria dura Bleeker, "Silures de Suriname," 1864, 18. 

One specimen, 119 mm. Creek in Mora Passage. (('. M. Cat. No. 1503.) 
One specimen, 112 mm. Mud-flats, Demerara. (I. U. Cat, No. 11938.) 
One specimen, 85 mm. Crab Falls. (C. M. Cat. No. 1516.) 
Head 5, width of head 1.5 in its length; eye 6 in the head, equal to interorbital; 

snout a little more than 2 in the head; width of first anal ray 2.6 in its distance from 

the caudal; scutes 8 + 15, the keels remaining distinct to the caudal. 

Occipital with two keels ending in rather strong spines behind; two nuchal 

plates keeled, other plates in front of the dorsal keeled. Eye with a shallow notch. 

Lower surface of head naked. 

Three long graduated teeth on each side of the upper jaw, seven much smaller 

ones on each side of the lower jaw. Lips with short warts about the mouth, other- 
wise with numerous long tentacles; free portion of the barbels much longer than 

the eye. 

Anal plate in the largest specimen composed of four plates, ventral buckler 

of about seventeen plates imperfectly joined. Three to eight plates between the 

lateral plates, depending on the position. 

Pectorals slightly emarginate, reaching past origin of ventrals; outer ventral 

ray prolonged, reaching to or beyond origin of last anal ray. Anal obliquely rounded. 

Upper caudal ray greatly prolonged, 180 mm. in length in a specimen 109 mm. 

long to base of caudal. Upper surface and fins reddish brown, caudal filament 

banded. 

Loricariichthys Bleeker. 

Loricariichthys Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 80 (maculatus). 
Parahcmiodon Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 80. 
Rineloricaria Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 81 (lima). 

Type, Loricaria maculata Bloch. 

Distinguished from Loricaria by its papillose lips. 

Key to the Guiana Species of Loricariichthys. 
a. Upper lip interrupted in the middle. A single series of plates between the lateral series of the belly; 
teeth very minute, twenty or more on each side of the lower jaw; ventral buckler formed of six 

plates; pectorals truncate. (Loricariichthys.) microdon. 

an. Upper lip well-developed. Two or more series of plates between the lateral plates of the belly; teeth 
twelve or fewer on each side of the lower jaw; ventral buckler formed of seven to sixteen plates. 
(Rineloricaria.) 
b. Xo keels on head or on the plates in front of the dorsal: usually two series of plates between the 

lateral series on the middle of the belly; sand-color, lower surface plain griseus. 

lib. Keels of the plates in front of the dorsal more or less evident ; three or more series of plates between 
the lateral plates of the belly; a dusky area or spot on cither side of base of first anal ray. 



EIGENMANN! THE FRESHWATER FISHES OF BRITISH GUIANA 245 

c. Head smooth; pores of the head black; plates of the middle of the belly frequently forming 
transverse scutes with the lateral plates. 
d. Pectorals, ventrals and anal spotted; an ocellus-like spot on the back in front of the 

dorsal; pores of anterior part of body not black brunneus. 

dd. Pectoral, ventrals and anal with a submarginal band platyurus. 

cc. Head strigilate steward. 

110. Loricariichthys microdon (Eigenmann) . (Plate XXX, fig. 1; Plate 

XXXII, fig. 1.) 
Loricaria acuta (not of Cuvier and Valenciennes) Muller and Troschel, in 

Schomburgk, Reisen, III, 1848, 631 (sand-bars of the Rupununi). 
Loricaria microdon Eigenmann, Ann. Carnegie Mus., VI, 1910, 7; Repts. Princeton 

Univ. Exp. Patagonia. Ill, 1910, 414. 

This species is closely allied to, if not identical with, L. acutus. Regan gives 
the lower lip of acutus as entire. 

I have examined the specimen mentioned by Muller and Troschel. 

Type, 90 mm. Rupununi. (Carnegie Museum Catalog of Fishes No. 1507.) 

Cotypes, two specimens, 76 and 112 mm. to tip of middle caudal ra.y. Rupu- 
nuni. (I. U. Cat, No. 11942.) 

Head 4-4.6; width of head 1.5-1.66 in its length; eye 6, equal to interorbital; 
snout 2+ in the head; width at first anal ray 5.33-6.33 in its distance from the 
caudal; scutes 17 or 18 + 14, the keels remaining separate throughout; upper lip 
not developed in the middle, entire on the sides in the largest specimen, fringed in the 
type; lower lip notched in the middle, deeply concave on each side in the type; 
the barbel extending considerably beyond the widest part of the lip, its free portion 
equal to the eye. Margin of the lower lip notched. Lips smooth. Lower lip 
in the largest specimen damaged, apparently reaching to the gill-opening, with a 
marginal fringe of tentacles. 

Teeth excessively minute, twenty or more on each side of the lower jaw; 
about eight conical teeth on each side of the upper jaw. 

Plates in front of the fourth dorsal raj' keeled, a pair of keels on the occipital; 
eyes with large angular notches, which encroach on the interorbital in the largest 
specimen. Anal plate pointed in front, bordered by two or three plates, the three 
together united into a larger plate in the largest specimen; ventral buckler formed 
of six plates, apparently only four in the largest; a single series of plates between the 
lateral series, two or more series farther forward. Ventral armature reaching to the 
gill-opening; lower surface of head naked. 

Pectorals truncate, the spine not produced, scarcely reaching ventral ; ventral 



246 MEMOIRS OF THE CARNEGIE MUSEUM 

rounded or the rays graduate, reaching to or a little beyond the origin of the anal. 
Dorsal spine equal to distance from snout to upper angle of gill-opening. 

Five or six cross-bands, the first extending down and forward from the third 
and fourth dorsal rays, the second being a large spot on the sides a little in front 
of the tip of the dorsal; dorsal spotted, most conspicuously so at its tip; pectorals 
dusky, or faintly spotted; ventrals a little lighter; anal hyaline; caudal faintly 
spotted, the tip of the lower lobe black. Upper caudal ray scarcely produced. 

111. Loricariichthys griseus (Eigenmann). (Plate XXX, fig. 2; Plate 

XXXII, fig. 2.) 
Loricaria griseus Eigenmann, Ann. Carnegie Mus., VII, 1910, 8; Repts. Princeton 

Univ. Exp. Patagonia, III, 1910, 414. 

Type, 131 mm. over all, 118 to tip of middle caudal rays. Konawaruk. 
(Carnegie Museum Catalog of Fishes No. 1504.) 

Cotypes, eleven specimens, 36-108 mm. to base of middle caudal ray. 
Konawaruk. (C, M. Cat, No. 1505a-c; I. U. Cat. No. 11926.) 

Cotypes, twenty-two specimens, 49-119 mm. to base of middle caudal ray. 
Bartica sand-bank. (C. M. Cat, No. 1506a-e; I. U. Cat, No. 11927.) 

Allied to L. punctatus and L. maculatus. 

Head 4.5-5; width of head 1.4-1.5 in its length; eye 5; interorbital 6.5-7; 
snout 2 in the head; width at first anal ray 5-5.33 in its distance from the cau- 
dal; scutes 18 or 19 + 11, the lateral keels remaining separate throughout. 

Upper lip well-developed, thickly papillose in the types, and always margined 
with well-developed tentacles, which are shortest, or absent, at the center. Lower 
lip in the type very broad, extending to the middle of the opercle, everywhere 
minutely warty, with a few larger warts on its anterior half, emarginate, otherwise 
with the edge smooth; lips ordinarily much narrower, not much wider than the 
part with larger warts, deeply emarginate, and the edge with minute tentacles; 
free portion of the barbel scarcely half the length of the eye. 

Teeth minute, about six to eight on each side of the upper jaw and twelve on 
each side of the lower, those of the upper jaw much smaller than the largest of the 
lower jaw. 

Head without ridges, an obscure groove on the occipital, sometimes continued 
in the first or first two nuchal plates; orbital notch broad and shallow, rounded, 
not encroaching on the interorbital; lower surface of the head naked; plates of 
the body without keels or ridges; anal plate normally bordered by three plates, 
but sometimes by four or five; two to four series of plates between the lateral plates 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 247 

of the belly; anterior border of the ventral armature on a line with the gill-open- 
ings, truncate or emarginate through the development of minute plates on the 
side in front. 

Pectoral truncate when half expanded, emarginate when depressed, the spine 
not prolonged, reaching second fourth of the ventrals. Ventrals usually rounded 
or truncate, scarcely reaching the anal; in a few of the Bartica specimens the in- 
ner rays are prolonged, reaching to near the fourth anal ray; upper caudal ray in 
a well-preserved specimen 2.5 times the length of the middle ray. 

Sand-colored, with the back everywhere spotted; very obscure cross-bars; 
dorsal, pectoral, and more obscurely the ventral colored like the back; upper 
part of caudal with cross-bars, tip of lower caudal lobe blackish; anal hyaline. 

112. Loricariichthys brunneus (Hancock). (Plate XXX, fig. 3; Plate 

XXXI, fig. 4.) 
Loricaria brunnea Hancock, Zool. Journ., IV, 1828, 247 (Demerara). — Cuvier 

and Valenciennes, Hist. Nat. Poiss., XV, 1840, 479 (copied). — Gunther, 

Catalogue, V, 1864, 260 (copied). — Eigenmann and Eigenmann, Occasional 

Papers Cal. Acad. Sci., I, 1890, 370. — Eigenmann, Repts. Princeton Univ. 

Exp. Patagonia, III, 1910, 415. 

Hancock's species of Loricaria from Demerara described as having a single 
series of plates along the ventral surface is undoubtedly the common Loricaria of 
that locality. There are several (about three) series of plates between the lateral 
plates of the belly, but these are so united and attached to the lateral series that 
they give the impression of a continuous plate extending entirely across the belly. 

Twelve specimens, 68-136 mm. to end of shortest caudal ray. Lama Stop- 
Off. (C. M. Cat. No. 1491a-d; I. U. Cat. No. 11928.) 

Seven specimens, 60-124 mm. Maduni Creek. (C. M. Cat. No. 1492a-o; 
I. U. Cat, No. 11929.) 

One specimen, 90 mm. Botanic Garden. (C. M. Cat. No. 1493a.) 

Six specimens, 68-110 mm. Demerara River below Wismar. (C. M. Cat. 
No. 1494a-6; I. U. Cat. No. 11930.) 

Two specimens, 76-105 mm. Christianburg Canal. (C. M. Cat. No. 1495a; 
I. U. Cat. No. 11931.) 

One specimen, 108 mm. Wismar. (C. M. Cat. No. 1496a.) 

Two specimens, 77-118 mm. Kumaka, Demerara. (C. M. Cat. No. 1497a; 
I. U. Cat. No. 11932.) 

Two specimens, 103-112 mm. Malali. (C. M. Cat, No. 1498a; I. U. Cat- 
No. 11933.) 



248 MEMOIRS OF THE CARNEGIE MUSEUM 

Twenty-four specimens, 73-151 mm. Gluck Island. (C. M. Cat. No. 1499a-e; 
I. U. Cat, No. 11934.) 

Eight specimens, 67-183 mm. Rockstone. (C. M. Cat, No. 1500a; I. U. 
Cat, No. 11935.) 

Four specimens, 77-135 mm. Tumatumari. (C. M. Cat. No. 1501a; I. U. 
Cat, No. 11936.) 

Six specimens. Rupununi. (C. M. Cat, No. 1502o-6; I. U. Cat, No. 11937.) 

Head 5.33-5.5; width of head 1.4-1.66 in its length; eye 6-6.5 in the head, 
interorbital 4.33, snout 2; width at first anal ray 4.5-5.33 in the distance of the 
anal from the caudal; scutes 18 + 13 to 16 + 15, the keels entirely united on the 
posterior scutes. 

Lips papillose, their margins fringed, more in the young, less in the adult; 
free part of barbel equal to eye. Head and scutes without keels. Seven to ten 
teeth on each side of the upper jaw, seven to nine on each side of the lower. 

Lower surface of head naked; a narrow orbital notch. 

Anal plate bordered by three plates; eleven to sixteen plates in the ventral 
buckler; three series of plates between the lateral series, which in the posterior 
part of the belly are frequently so united as to form a transverse scute; middle 
plate sometimes more distinct, Armature developed to between the anterior angle 
of the gill-opening. 

Pectoral truncate, the outer ray sometimes slightly produced, reaching about 
to origin of ventrals. Outer ventral ray sometimes produced, reaching to base of 
first or beyond base of last anal ray. Dorsal spine a little longer than the head; 
caudal lunate, the upper ray much, and the lower sometimes less, produced. 

Pores of the head black; a dark spot in front of the dorsal, not quite equal to 
the eye, margined by a lighter one, and this flanked by a dark streak on each side, 
having the appearance of an obscure ocellus, becoming very obscure in the largest 
specimen. Dorsal surface marbled, four or five dark bands behind the dorsal, 
evident even in the largest specimens. Fins spotted, tip of caudal blackish, the 
latter with cross-bars, a basal and submarginal bar in the largest, and several in the 
smaller, in which the caudal is much darker, sometimes nearly black; a small dark 
spot on either side of the base of the first anal ray. 

113. Loricariichthys platyurus (Muller and Troschel). (Plate XXX, fig. 4; 

Plate XXXI, fig. 3.) 
Loricaria platyura Muller and Troschel, in Schomburgk, Reisen, III, 1848, 631 
(Rupununi). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
415. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 249 

Loricaria submarginata Eigenmann, Ann. Carnegie Mus., VI, 1910, 10; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 414. 

One specimen, 142 mm. over all, 92 mm. to tip of middle caudal rays. Creek 
below Potaro Landing. (C. M. Cat. No. 1510.) 

Closely allied to L. brunneus. An examination of the type of L. platyurus in 
Berlin leaves no doubt about the identity of the species. 

Head very little less than 5 in the length; width of head 1.5 in its length; eye 
5.5, interorbital 4, snout 2 in the head; width of first anal ray 5 in its distance from 
the caudal; scutes 12 + 15, the lateral ridges almost completely united on the last 
seven scutes. 

* Lips well-developed, with a marginal series of fringes, interrupted in the middle 
in front, and with rather long warts. Lips not nearly reaching gill-opening. Seven 
or eight teeth in each side of each jaw. Free portion of the barbel about equal to 
the eye. 

Head without ridges, plates in front of the dorsal but faintly keeled. Orbital 
not shallow, narrowly rounded. 

Anal plate bordered by three plates in front, the ventral buckler formed of 
seven to thirteen plates; about three series of plates between the lateral plates, these 
with the lateral plates forming in the posterior part regular transverse scutes, the 
scutes becoming more numerous and less regular in front. Armature truncate in 
front, not extending quite to the anterior angle of the gill-opening. 

Pectorals slightly emarginate, the inner angle rounded, extending to the origin 
or second fourth of the ventrals; ventral rays graduated, the outer ray scarcely pro- 
longed, reaching to the base of the last anal ray. 

Pores of the head and to below the dorsal jet-black; obscure cross-bands, that 
below the base of the dorsal and that below its tip most prominent. No ocellus 
in front of dorsal. Dorsal spotted, the submarginal spots most prominent. Pec- 
toral, ventral, and anal each with a broad submarginal dark band; base of caudal 
and the tips, exclusive of the upper ray, black. Upper caudal ray much prolonged, 
forming 51 mm. of the total length. 

114. Loricariichthys stewarti (Eigenmann). (Plate XXX, fig. 5.) 
Loricaria stewarti Eigenmann, Ann. Carnegie Mus., VI, 1910, 9; Repts. Princeton 

Univ. Exp. Patagonia, III, 1910, 414. Allied to L. teffeanus and L. konopickyi. 

Type, 81 mm. over all, 64 mm. to tip of middle caudal ray. Chipoo Creek, a 
tributary of the Ireng. (Carnegie Museum Catalog of Fishes No. 1508.) 

Cotypes, eleven specimens, 52-68 mm. to tip of middle caudal rays. Chipoo 
Creek. (C, M. Cat. No. 1509a-c; I. U. Cat. No. 11943.) 



250 MEMOIRS OF THE CARNEGIE MUSEUM 

Allied to L. brunneus, the head strigilate. 

Head 5; width of head 1.5 in its length; eye 6, interorbital 4.5, snout 2.2 in 
the head; width at first anal ray 5.33-5.66 in its distance from the caudal; scutes 
17 + 13 to 14 + 15. the lateral keels nearly merged behind. 

Upper lip with a marginal fringe of tentacles; lower lip papillose, except near 
the margin, with a marginal series of tentacles, which do not extend to the gill- 
opening. 

About six teeth in each side of the upper jaw and eight on each side of the 
lower. 

Head and body strigilate; lateral keels weak, other scutes (except nuchal 
scutes) not carinate; occipital with a pair of slightly diverging keels, the two 
foUowing nuchal plates each with a pair of keels. 

Orbital notch narrow and deep, eye nearly circular. Lower surface of the 
head naked, except for a narrow entering triangle in front of the gill-opening. 

Anal plate margined by three large plates, the anal buckler composed of eleven 
plates; posteriorly three, anteriorly five, series of plates between the lateral series. 
Ventral armature fully developed (even in the smallest individuals) to between the 
anterior angle of the gill-openings. 

Dorsal spine about equal to the head. Pectorals truncate, reaching ventrals. 
Ventrals rounded, or the outer ray slightly produced, reaching the anal. Upper 
caudal ray forming considerably more than a third of the total length. 

Dark, with the usual cross-bars; pores black, but not conspicuous. Dorsal 
rays spotted, a large spot near the tip of the three first rays. Pectorals, ventrals, 
and anal barred, the bars most evident on the first rays. Base and margin of caudal 
black, the outer rays barred. 

Hemiodontichthys Bleeker. 
Hemiodontichthys Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 81. 

Type, Hemiodon acipenserinus Kner. 

Intermediate in shape between Loricaria and Farlowella, the snout produced 
and expanded at the tip, and having numerous small recurved spines. 

115. Hemiodontichthys acipenserinus (Kner). 
Hemiodon acipenserinus Kner, Denkschr. Akad. Wiss. Wien, VI, 1853, 92, pi. 7, 

fig. 2 (Rio Guapore, Mattogrosso) . 
Loricaria acipenserina Gunther, Catalogue, V, 1864, 260 (copied). — Vaillant, 

Bull. Soc. Philom., (7), IV, 1880, 159 (Calderon). 
Hemiodontichthys acipenserinus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 251 

(2), II, 1889, 34 (Manacapurii; Hyavary); Occasional Papers Cal. Acad. Sci., 
I, 1890, 359.— Regan, Trans. Zool. Soc. London, XVII, 1904, 296.— Eigen- 
mann, Ann. Carnegie Mus., IV, 1907, 120, pi. 35, fig. 1 (Corumba); Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 415. 

One specimen, 95 mm. to tip of middle caudal rays, 118 over all. Gluck 
Island. (C. M. Cat, No. 1514.) 

Head 3.25; width of head 2.2 in its length; eye 8 in head, 4.5 in snout; inter- 
orbital 6.5 in head. Width of first anal ray 5 in its distance from the caudal; 
scutes 11 + 16, the keels remaining separate. Head, and all the plates in front 
of the dorsal, with wavy longitudinal ridges. A deep inturned orbital notch. 

Lips very broad, extending slightly beyond the anterior angle of the gill- 
opening, faintly papillose, the margin variously nicked and fringed. Teeth in the 
lower jaw very minute, none in the upper jaw. Anal plate bordered by three 
larger plates, the four forming the ventral buckler. A median series of three plates 
between the lateral series in front of the buckler. 

Pectorals truncate, reaching ventrals;' ventrals rounded, reaching anal; anal 
rounded. Dorsal spine equals head without snout. Caudal oblique, very faintly 
emarginate, the upper ray more than three times the length of the middle ray. 

Upper surface reddish brown, sides of head and lips marbled, five bars across 
the back behind the dorsal. Fins faintly barred. 

Harttia Steindachner. 
Harttia Steindachner, " Siisswasserfische d. sudostlichen Brasilien," iii, 1876, 110 

{loricariiformis) . 

Loricariiform; teeth numerous, in about equal numbers in both jaws; snout 
not produced into a rostrum. 

116. Harttia platystoma (Giinther). (Plate XXX, fig. 6; Plate XXXI, figs. 

1-2.) 
Loricaria platystoma Gunther, Proc. Zool. Soc. London, 1868, 236, figs. 4, 5 

(Surinam). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 

37; Occasional Papers Cal. Acad. Sci., I, 1890, 385; Proc. U. S. Nat. Mus., 

XIV, 1891, 39. 
Oxyloricaria platystoma Regan, Trans. Zool. Soc. London, XVII, 1904, 298. 
Harttia platystoma Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

415. 

Twelve specimens, 53-160 mm. Rockstone. (C. M. Cat. No. 1511a-c; I. U. 
Cat. No. 11939.) 



252 MEMOIRS OF THE CARNEGIE MUSEUM 

Four specimens, 53-114 mm. Konawaruk. (C. M. Cat. No. 1512a; I. U. 
Cat. No. 11940.) 

Twenty specimens, 52-127 mm. Warraputa. (C. M. Cat. No. l-513a-e; I. U. 
Cat. No. 11941.) 

Head 4.4-5; width of head 1.33 in its length; eye 6, interorbital 5, snout not 
quite 2 in the head; width of the first anal ray 4.25-4.5 in its distance from the 
caudal; scutes 19 + 10 to 17 + 12, the lateral keels very feeble in front of the 
middle of the ventrals, entirely united on about the last two scutes. 

Lips narrow, papillose, with a very narrow fringe, free portion of the barbel 
about one-fourth the diameter of the eye. 

Teeth very numerous in both upper and lower jaws. 

Lower surface of the head naked, except for a triangular plate in front of the 
gill-openings. Head and scutes without keels of any sort; orbit without a notch. 

A pair of anal plates; ventral buckler formed of about forty plates; eight to ten 
series of small plates between the lateral plates, becoming minute and isolated on 
breast and reaching to the gill-opening. The plates are only partially developed 
in specimens 100 mm. long. 

Dorsal spine about 1.4 times as long as head; pectorals falcate, reaching past 
middle of ventrals in adult. Ventrals lanceolate, reaching past origin of anal, 
which is also lanceolate. Caudal deeply lunate, the middle rays two-fifths the 
length of the lowest and two-sevenths the length of the uppermost ray. 

Back marbled; seven cross-bands, showing in the young only. Dorsal spotted, 
the anterior ray tending to uniform blackness. Upper surfaces of pectoral and 
ventral barred, most intensely in the outer rays; anal hyaline or faintly barred in 
front. Lower caudal lobe and a lunate spot on the middle of the caudal black, 
upper lobe barred. 

Farlowella Eigenmann and Eigenmann. 
Acestra (not of Dallas, 1852) Kner, Denkschr. Akad. Wiss. Wien, 1853, 93. 
Farlowella Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., I, 1890, 355 (acus). 

Type, Acestra acus Kner. 

Loricariiform ; body narrow, snout slender, prolonged into a long rostrum; 
dorsal in part over ventrals. 

117. Farlowella hargreavesi sp. nov. (Plate XXXII, fig. 3.) 
Type, a single specimen, 65 mm. to base of caudal. Locality not given. 
Head to end of temporal plate 3.75 in the length; its width not quite one-third 
its length; eye 12 in the head to end of the temporal plate; anterior margin of the 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 253 

eye equidistant from tip of snout and anus; snout in front of the naked area about 
the mouth 3 in the distance to the anus; postorbital part of the head 3.5 in the 
snout. Distance from supraoccipital to the dorsal 6 in the length; snout long, 
slender, granular, expanded at the tip. 

Seven plates between the supraoccipital and the dorsal; lateral plates thirty- 
three (14 + 19). 

Much faded, but outer margins of caudal evidently dark. 

Named for Mr. T. Sydney Hargreaves, author of "The Fishes of Guiana," 
who presented the specimen to the Museum of Georgetown. 

Order HETEROGNATHI. 
Family CHARACID.E. 

= Characini Muller, Archiv fiir Naturg., IX, i, 1843, 323. 

= Characinidce Richardson, Encycl. Brit., ed. 8, XII, 1856, 245. 

> Chamcidce Gill, Mem. Nat, Acad. Sci., VI, 1893, 131. 

This large family includes fishes of nearly all shapes and sizes, and inhabiting 
all sorts of fresh-waters in tropical South America. The species found in Guiana 
are distinguished from the other fishes of that country by the presence of scales, a 
short dorsal fin without spines, and a short adipose dorsal fin. The latter, however, 
is absent in Hoplias, Erythrinus, Carnegiella, Pcecilocharax, and Nannostomus. 

Key to the Guiana Genera of Character. 
a. Mouth protractile; no tenth; gills with forward-directed lamellae. An adipose fin; upper jaw rudimentary, 

lower jaw large, well-developed. (Bivibranchiina:.) Bivibranchia. 

on. Mouth not protractile. 

b. Teeth none; an adipose fin; lower jaw firm, with a thin edge; intestine very long; gill-rakers none or 
modified. ( Curimatirwe.) 
c. Lateral line incomplete; caudal naked; tongue long, narrow; mouth very oblique, cyprinodontiform. 

Curimatopsis. 
cc. Ventral surface not spiniferous; lateral line complete; tongue broad, adnate; mouth terminal or 
inferior. 

d. Caudal lobes densely scaled Curimatella. 

dd. Caudal lobes naked Curimatus. 

(ccc. Post-ventral surface trenchant, spiniferous; predorsal area scaled Psectrogaster.) 

66. Teeth minute on the margins of fleshy lips, movable; gill-membranes joined to the isthmus. (Cf. 666.) 

e. Gills normal; mouth large, evertible to form a circular sucking disk; teeth numerous on both lips, 

in single series on the sides, in two in the middle; a predorsal spine; scales rough; species 

of large size. (Prochilodime.) Prochilodus. 

ee. Fourth gill-arch dilated behind, its surface with corrugations which fit into similar ones on the con- 
cave fifth arch; mouth small; no predorsal spine; species small. (Chilodince.) 
f. Anal emarginate, the highest rays extending beyond the tip of the last; scales with serrate 
margins; feeble teeth in both jaws, those of the upper jaw bifid Tylobronchus. 



254 MEMOIRS OF THE CARNEGIE MUSEUM 

ff. Anal truncate, the highest ray not reaching the base of the last; scales entire; teeth in both 

jaws entire Chilodus. 

666. Teeth on the lower jaw none, or else confined to the sides of the jaw; gill-arches normal; jaws firm. 

(Cf. 6666.) (Hemiodontina.) 

(j. No fontanel; teeth of the upper jaw pectinate, directed backward, their margins in a straight 

• transverse line, teeth of the lower jaw confined to the sides Parodon. 

gg. Large fontanels; teeth in the upper jaw in a crescent, none in the lower jaw. 

h. Scales below the lateral line of the same size as those above it Hemiodus. 

hh. Scales below the lateral line larger than those above it Anisitsia. 

6666. Teeth well-developed in both jaws, fixed. 

i. Caudal forked (Cf. Hydrolicus). 

j. Teeth truncate, notched, or denticulate; or, if conical, the species small, and without an adipose 

fin. 

k. Teeth conical; no adipose fin; no fontanel; mouth short, oblique, cyprinodontiform; two 

series of teeth in the lower jaw. (Pyrrhuh'iniur.) 

I. Premaxillary with two series of teeth Pyrrhulina. 

kk. Not as under k. 

m. Ventral edge without serrse. 

n. Preventral area not expanded; pectorals small. 

o. Premaxillary and dentary each with a single series of teeth. 

p. No frontal fontanel, posterior fontanel, if present, minute; adipose fin 

present or not. ( Nannostomatince.) 

q. Skull truncate; no occipital process; no fontanel; teeth usually 

incisor-like, notched at tips; no lateral fine. 

r. No adipose fin; teeth broad at tip, with five equal points. 

Nannostomus. 
rr. Adipose fin well-developed. 

s. Pectorals normal; teeth with five equal or subequal 

points Pcecilobrycon. 

ss. Pectorals fleshy flaps, edged with filaments; teeth three- 

to five-pointed, the middle point much the longer. 

Archicheir. 

qq. A triangular occipital process; a small circular occipital fontanel; 

adipose fin well-developed; lateral line complete; teeth 

usually three-pronged Characidium. 

pp. A large frontal and (usually) a parietal fontanel. 

t. Gill-membranes united, usually joined to the isthmus; mouth 

small, with little or no antero-posterior extent. (Ano- 

stomatinw.) 

u. Teeth of the upper jaw serrate or multicuspid. 

v. Snout elongate, subcircular in cross-section; mouth 

minute, vertical; gill-membranes joined to the 

isthmus Anostomus. 

vv. Snout elliptical in cross-section, not produced; the mouth 

terminal Schizodon. 

mi. Teeth of the upper jaw serrate in young, truncate in adult; 

mouth directed obliquely upward. . Schizodontopsis. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 255 

uuu. Teeth in both jaws obliquely truncate, directed obliquely 

forward toward a median point Leporinus. 

/(. Gill-membranes free from the isthmus and from each other. 
w. Dorsal with fifteen rays. (Cr&imchince.) 

x. An adipose fin; mouth large, maxillary extending to 

below middle of eye. Crenuchus. 

xx. No adipose fin; mouth small, maxillary extending to 

below anterior margin of eye Poecilocharax. 

ww. Dorsal short. (Aphyocharacinoe.) 

y. Lateral line complete; maxillary with a few teeth. 

Odontostilbe. 
yy. Lateral line incomplete. 

z. Caudal naked; teeth pointed, with a notch on each 

side Aphyocharax. 

zz. Caudal scaled Aphyodite. 

oo. Premaxillary with two or more series of notched teeth. (See .-1.) 
A . Gill-membranes united, free from the isthmus. Dorsal entirely behind the ventrals, in part over the anal ; 
teeth pluricuspid incisors, a single tooth in the front row of each premaxillary; mouth small. 
(Iguanodectince.) 

B. Breast not compressed to an edge Iguanodectes. 

BB. Breast compressed to an edge Piabucus. 

A A. Gill-membranes free from each other and from the isthmus; opercle not prolonged. 

C. No predorsal spine. 

D. Preventral area with a median edge; pectorals small, placed low; anal basis nearly horizontal; 

mouth large, with canines. (Agoniatince.) Agoniates. 

DD. Preventral area rounded, sometimes very narrow. 

E. Lower jaw with a single series of teeth. {Tctragonopteriiue.) 
F. Gill-rakers setiform. 

G. Caudal scaled; anal with a basal sheath of scales. 

//. Lateral line much decurvedin front Tetragonopterus. 

////. Lateral line not greatly decurved, scales entire. 

/. Lateral line complete; predorsal area with a median series of scales: five 
teeth in the inner series of the premaxillary; second suborbital not 

completely covering the cheek Mcenkhausia. 

II. Lateral line incomplete; caudal lobes equal. 

J. Maxillary with teeth along its entire margin Pristella. 

/./. Maxillary with few or no teeth Hemigrammus. 

GG. Caudal naked. 

K. Preventral area with several series of normal scales. 

L. Lateral line incomplete. Maxillary border a simple curve; origin of anal 
behind origin of dorsal; scales cycloid. 

M. Pectoral normal Hyphessobrycon. 

MM. Pectoral archaic, a fleshy lobe surrounded by a fringe of filaments. 

Dermatocheir. 
LL. Lateral line complete. 

2V. Maxillary border meeting premaxillary border at a right angle, its 



256 MEMOIRS OF THE CARNEGIE MUSEUM 

margin then describing a quarter circle and continuing in a di- 
rection nearly parallel with that of the premaxillary. 

Creatochanes. 
N N. Anterior maxillary-premaxillary border forming a simple curve. 
0. Teeth of the sides of the lower jaw abruptly smaller. 

P. Premaxillary teeth in three series; anal of not more than 

fourteen rays Creagrutus. 

PP. Premaxillary teeth in two series. 

Q. Four teeth in the inner series of the upper jaw; second 
suborbital covering entire cheek. Bryconamericus. 
QQ. Five teeth in the inner series of the lower jaw. 
R. Scales cycloid. 

S. Predorsal line scaled Astyanax. 

SS. Predorsal line naked Poecilurichthys. 

RR. Scales ctenoid Ctenobrycon. 

00. Teeth of the sides of the lower jaw graduated Deuterodon. 

A" A". Preventral area with two series of large overlapping scales Phenacogaster. 

(FF. Gill-rakers short, lanceolate Scissor.) 28 

EE. Lower jaw with two series of teeth, the inner series consisting of a pair of conical teeth within 
the outer series, and beginning at a greater or less distance from these a series of minute 
teeth on the sides. (Bryconinm.) 
T. Scales alike above and below. 

U. No fontanels Holobrycon. 

U U. Two large fontanels Brycon. 

TT. Scales much larger above the lateral line Chalceus. 

CCA predorsal spine, scale-like; caudal scaled. (Stethaprioninm.) Fowlerina. 

nn. Preventral area compressed, trenchant, more or less expanded; pectorals large. 
V. Body elongate, lateral line continued to the tail. (Chateau ita.) 

Chalcinus. 
V V. Body short; the lateral line deflected to before the anal; sternum much 
expanded; skull with longitudinal crests. (GasU-nipclccimc.) 
IF. No adipose fin; maxillary with a single, large, hooked tooth. 

Carnegiella. 
WW. Adipose fin present; maxillary with large, hooked teeth; premaxillary 

teeth in a single series Gasteropelecus. 

mm. Belly and preventral area trenchant and serrate. 

X. All teeth in the jaws in a single series. (SerrasalmincB.) 

Y. A series of teeth on each side of the palate Serrasalmo. 

YY. Palate without teeth. 

Z. Teeth with simple cutting edge Pygocentrus. 

ZZ. Teeth serrate Pygopristes. 

XX. Premaxillary teeth in two series. (MylvruB.) 
a. Mandible with a single series of teeth. 

p. Abdomen serrate before and behind the ventrals; premaxillary teeth 
conical; lower jaw much projecting Catoprion. 

28 The place from which Scissor came is not known. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 257 

/S/3. Abdomen serrate behind the ventrals only. 

y. Anal bilobed Mylesinus. 

77. Anal deeply emarginate Acnodon. 

aa. Mandible with a pair of conical teeth, premaxillary teeth trenchant. 

S. Adipose fin long Metynnis. 

00. Adipose fin short, the two series of teeth of the upper jaw separated 

from each other Myloplus. 

odd. Adipose fin short; the two series of teeth of the upper ,jaw close together, 
teeth of the outer row forming a continuous series of incisors. 

Myleus. 

jj. Teeth conical ; gill-membranes free from the isthmus. 

e. Pectorals very large; belly compressed; body long and narrow. (Cynodmdiruc.) 

f. Abdominal area much shorter than anal basis; caudal lunate; ventrals' small; pec- 
torals reaching anal; anal with about eighty rays; dorsal over anal; scales 

cycloid Cynodon. 

ff. Abdominal area much longer than anal basis; caudal rounded; pectorals overlapping 
ventrals; origin of ventrals about equidistant from origin of anal and upper 
angle of gill-opening; anal with about thirty-five rays; dorsal in front of anal; 

scales ctenoid Hydrolicus. 

«. Not as under e. 

1?. No teeth on palate; snout not prolonged. (Characince.) 
8. Both jaws with antrorse, tooth-like structures. 

t. Anal short, of fewer than thirty rays, deeply emarginate, its origin behind 
the vertical from the last dorsal ray. Clavicle not notched to re- 
ceive the base of the pectoral Exodon. 

u. Anal long, its origin in front of the vertical from the first dorsal ray, its 
margin straight; clavicle with a shallow notch to receive the base of 

the pectoral Roeboides. 

88. Jaws without antrorse, tooth-like processes. 

k. Preopercle without a spine ; anal margin straight or nearly so. 

X. Scales forty to sixty in the lateral line; clavicle with a deep notch 
to receive the base of the pectoral, the lower part of the clavicles 
blade-like, sub-parallel ridges bounding the breast on either 
side and ending in a spine in front and behind; premaxillary and 
dentary with a canine at each end; two series of teeth between 
the canines of the premaxillary, and a single series between 
those of the mandible; anal very long, its origin in advance of 
the vertical from the first dorsal ray. 
m. Lateral line complete; pectoral overlapping the ventrals. . Charax. 

nil. Lateral line incomplete; pectoral archaic Asiphonichthys. 

XX. Over ninety scales in the lateral line; clavicle with a notch; lower mar- 
gins of the clavicles forming a much less prominent ridge than 
in Charax, without spines; origin of anal behind the vertical 
from the first dorsal; teeth as in Charax, but an additional and 

much larger median canine on the dentary Cynopotamus. 

int. Interopercle drawn out into a prominent spine; anal margin deeply concave; 
origin of anal behind the vertical from the origin of the dorsal. 



258 MEMOIRS OF THE CARNEGIE MUSEUM 

v. Premaxillnry with a canine at each end and a double row of teeth 
between them; mandible with three or four canines in front; 
the last one much the largest. Maxillary with a canine at its 
upper end and pectinate teeth along its margin; clavicle notched, 
the lower angle of the notch produced, scale-like; cheeks partly 

naked Acanthocharax. 

w. Premaxillary teeth in a single series (rarely one or two teeth forming 
a second series) ; no canines at the ends of the series, but the 
anterior teeth graduated, the third tooth largest, canine-like; 
upper angle of maxillary without a canine, the teeth graduated 
in both directions from about the fifth tooth. Anterior teeth 
of the lower jaw canines, of which the first is large, the second 
very small, the teeth from the second to the sixth graduated, 
the sixth being about the size of the first; first teeth of the pre- 
maxillary graduated, the third tooth being the largest; clavicle 

not notched Heterocharax. 

vn. Teeth on palate; snout prolonged; body long, cylindrical or subcylindrical. 

I. Snout moderate; some of the teeth canines; anal long. {Acestrorhamphinoe.) 
Maxillary with two canines, slipping under the preorbital for its entire 

length Acestrorhynchus. 

If. Snout very long, slender, with small, conical teeth; anal short. Lepisosteus- 
like. ( Hydrocynincs.) A single series of teeth in each jaw. Hydrocynus. 
ii. Caudal rounded ; mouth large, teeth conical, some of them canines. No fontanels; no adipose dorsal. 
(Erythrininm.) 

o. Walls of the air-bladder normal; maxillary with a canine anteriorly Hoplias. 

oo. Walls of the anterior portion of the air-bladder cellular; maxillary without a canine. 

jr. Pterygoids with teeth; dorsal rounded Hoplerythrinus. 

irir. Pterygoids without teeth; dorsal fin angular or pointed Erythrinus. 

Subfamily Bivibranchiin^. 

Bivibranchia gen. nov. 

Mouth minute, with a row of movable multicuspid teeth in the fleshy upper 
lip, none in the lower lip; upper jaw pointed, freely protractile; nares separated 
by a flap only; gill-membranes narrowly joined to the isthmus at a point below the 
posterior margin of the eye; gills highly modified; gill-rakers on the anterior face 
of the anterior arch fleshy, dendritic, a shorter papillifonn series on its posterior 
face, interlocking with the anterior rakers of the second arch; similar interlocking 
rakers between subsequent arches; broad lamella? extending inward as the gill- 
filaments extend outward on each arch, the lamellae with papillated ridges corre- 
sponding to the rakers, so that the ridges of succeeding lamellae interlock. 

Scales firm, cycloid. Lateral line complete, scarcely decurved; fins naked; 
anal very small; middle caudal rays with broad membranes; vertebra? 17 + 18 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 259 

(not counting the coalesced vertebra?); adipose lid covering almost the entire eye; 
fontanels both large, the frontal fontanel becoming linear in front. 

A series of valvular organs on the roof of the mouth ; the first a cushion about 
as broad as long, with a transverse ridge in front and two blunt papillse near its 
posterior edge, a blind pocket extending under it from behind; the second valve 
consisting of a pair of soft flaps on the sides of the roof of the mouth, extending 
obliquely downward and backward; the third a pair of triangular cushions, the 
point extending forward and the base extending backward, free; the fourth a trans- 
verse membrane with three pendant lobes in the middle; a pair of short papillated 
flaps between the third and fourth valves. No tongue; a series of slender papillse 
across the floor of the mouth in front of the gills, and opposite the anterior margin of 
the triangular cushion; sides of the mouth in front of the gills with oblique series of 
papillse. Two air-bladders, connected by a slender thread only, the anterior about 
as large as the eye, the posterior very delicate, large, straight, and conical, reaching 
to the anus, 2.5 in the length. Alimentary canal about equal to the length without 
the caudal, with eleven cceca; a highly muscular gizzard-like stomach with longi- 
tudinal ridges extending into the lumen. The alimentary canal contains much 
sand, which suggests trituration in the muscular stomach. 

118. Bivibranchia protractila sp. nov. (Plate XXXIII, figs. 1-5.) 

Type, 115 mm. Bartica sand-bank. (Carnegie Museum Catalog of Fishes 
No. 1873.) 

Cotypes, eight specimens, 58-67 mm. -Bartica sand-bank. (C. M. Cat. No. 
1874a-c; I. U. Cat. No. 12158.) 

Cotypes, eighteen specimens, 77-110 mm. Rockstone sand-bank. (C. M. 
Cat. No. 1875a-c; I. U. Cat. No. 12159.) 

Cotypes, three specimens, 22-115 mm. Crab Falls. (C. M. Cat. No. 1876; 
I. U. Cat. No. 12243.) 

Head 3.6; depth 4.6-5; D. 11; A. 9; scales 7 or 8—55 to 60—3 or 4; V. 11; 
P. 17; eye equals snout, 3.2 in the head, .8-1 in the interorbital. 

Very similar to Albula vulpes. Dorsal and ventral profiles equal and gently 
arched; profile of head slightly arched, the head subtriangular in cross-section, 
flat above, its sides sloping toward its ventral edge; predorsal area broad, without 
a regular median series of scales; belly broad and rounded, without a regular 
median series of scales. Occipital process 6 in the distance from its base to the 
dorsal. Snout pointed, much more so in the very young, the mouth very narrow, 
less than half the width of the interorbitals. Upper jaw greatly protractile, the 



260 MEMOIRS OF THE CARNEGIE MUSEUM 

premaxillaries minute and free from each other, the maxillary a slender curved 
bar, its posterior end curved upward, slipping under the preorbital, not reaching 
to below the nares; the mandibles out of proportion, nearly 2.5 times longer, the 
articulation under the anterior part of the orbit. About eight tricuspid teeth 
inserted in the lip some distance from its anterior margin. No teeth in the lower 
jaw. 

Cheeks narrow, covered by the second suborbital, there being a naked area 
only under its anterior angle. 

Scales hard, in regular series on the sides, the uppermost series of the sides 
meeting rather irregularly behind the occipital process; in the angle between these 
series and the dorsal there are first a few median scales and then two series of 
scales which end at the dorsal; fins all naked; axillary scale of the ventral more 
than half as long as the fin; humeral process continued as an adnate adipose ridge. 
Scales all highly iridescent, without lines. 

Origin of dorsal about an orbital diameter nearer the snout than to the caudal; 
dorsal pointed, the first rays about 4.5 in the length, the penultimate less than 
half as long as the longest; adipose fin small; caudal very deeply forked, the lobes 
pointed, a little over one-fourth of the length; anal very small, emarginate, the 
tip of the highest ray about reaching the tip of the last; origin of ventrals under the 
posterior part of dorsal, reaching half-way to first or sometimes to last anal ray; 
pectorals reaching nearly half-way to tip of ventrals. 

Straw-colored, upper caudal lobe light orange, ranging to yellow below. 
Highly iridescent, a dark streak along the shoulder just behind the opercle; bases 
of scales of the upper part of the sides dark. 

This species is abundant about the sand-bars in the lower Essequibo. 

Subfamily Curimatin^e. 
Curimatopsis Steindachner. 
Curimatopsis Steindachner, "Ichthyologische Beitrage," v, 1876, 33. 
Type, Curimatopsis macrolepis Steindachner. 

This genus has heretofore not been taken outside of the Amazon basin. 
Teeth none; mouth small, very oblique, cyprinodontiform; tongue long, 
narrow, free; lateral line developed on a few scales only. 

119. Curimatopsis macrolepis Steindachner. 
Curimatus (Curimatopsis) macrolepis Steindachner, "Ichthyologische Beitrage," 
v, 1876, 33 (Tabatinga; Manacapuru; Mouth of the Rio Negro). 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 261 

Curimatopsis macrolepis Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 

1889, 414 (Tabatinga; Lake Hyamary; Cudajas); Proc. U. S. Nat. Mus., XIV, 

1891, 45.— Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 420. 

Forty-two specimens, the largest 53 mm. Maduni Creek. (C. M. Cat. No. 
2086a-j; I. U. Cat, No. 12273.) 

One specimen, 43 mm. Cane Grove Corner. (C. M. Cat. No. 1287a.) 

Eighty-eight specimens, the largest 57 mm. Lama Stop-Off. (C. M. Cat. 
No. 1288a-o; I. U. Cat. No. 12274.) 

One specimen, 63 mm. Botanic Gardens, Georgetown. (C. M. Cat. No. 
2093.) 

Two specimens, about 37 mm. Konawaruk. (C. M. Cat. No. 2096; I. U. 
Cat, No. 12280.) 

Three specimens, 40 mm. Gluck Island. (C. M. Cat. No. 2099a-6; I. U. 
Cat. No. 12283.) 

Sixteen specimens, the largest 40 mm. Rockstone. (C. M. Cat. No. 2102a-b; 
I. U. Cat. No. 12285.) 

Three specimens, 41-43 mm. Wismar. (C. M. Cat. No. 2103a-6; I. U. Cat. 
No. 12287.) 

Similar to Curimatus spilurus, but readily distinguished by the shape of its 
mouth, or the incomplete lateral line. Occurring as it does in many places with 
spilurus, it requires a close scrutiny to pick out individuals of this species from 
among the young of the latter. In the collection from Rockstone, for instance, 
sixteen specimens of this species were mixed with 323 of spilurus. 

Head 4.2; depth about 3; D. 11; A. 8 or 9; scales 29 or 30, of which 3-5 are 
with pores; eye .75 in snout, 2.8 in head, and 1.25 in interorbital. 

Compressed, the preventral area rounded, with a median series of scales, the 
postventral area more narrowly rounded; predorsal area rounded, with a median 
series of about eight scales; mouth small, the lower jaw entering the profile; maxil- 
lary nearly vertical, its anterior margin convex; eye large, the cheek narrow, covered 
by the suborbital; interopercle at the angle as wide as the cheek. 

Scales with several slightly diverging striae, regularly imbricate, nowhere 
notably smaller; fins naked. 

Fins small, dorsal considerably nearer snout than to caudal; caudal about 4 in 
the length; anal small, slightly emarginate, the anterior ray extending beyond the 
tip of the last; ventrals reaching anus; pectorals not to ventrals. 

A plumbeous or silvery band ending in a well-defined spot on the last scales; 
upper part of eye sometimes red; anal yellow; upper part of caudal orange at its 
base, fading out backward. 



262 MEMOIRS OF THE CARNEGIE MUSEUM 

Curimatella Eigeiimann and Eigenmann. 
Curimatella Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 7. 

Type, Curimatus lepidurus Eigenmann and Eigenmann. 

Teeth none; lateral line complete; caudal lobe densely scaled; narrow margin 
of the broad tongue free. 

120. Curimatella alburna (Muller and Troschel). 
Anodus alburnus Muller and Troschel, Horse Ichth., I and II, 1845, 26, pi. 4, 

fig. 3 (Lake Amucu, Brit. Guiana); in Schomburgk, Reisen, III, 1848, 633 

( Lake Amucu) . 
Curimatus alburnus Kner, "Familie der Characinen," i, 1859, 8 (Rio Guapore, 

Matto Grosso). — Steindachner, " Ichthyologische Beitrage," v, 1876, 338 

(Teffe); "Flussfische Siidamerika's," ii, 1881, 36 (Amazon). — Eigenmann and 

Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 10 (Surinam; Coary; Lake 

Hyavary; Tonantins); Proc. U. S. Nat, Mus.,XIV, 1891, 46.— ? Boulenger, 

Trans. Zool. Soc. London, XIV, 1896, 34 (Descalvados). — Pellegrin, Bull. 

Mus. d'Hist. Nat., V, 1899, 157 (Apure). — Eigenmann, Ann. Carnegie Mus., 

IV, 1907, 1124 (Bahia Negra). 
Curimatella alburna Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

420. 

Seven specimens, 90-115 mm. Rupununi. (C. M. Cat, No. 2105a-d; I. U. 
Cat, No. 12289.) 

Eighteen specimens, 55-65 mm. Twoca Pan. (C. M. Cat, No. 2106a-d; 
I. U. Cat. No. 12290.) 

Head 3.4-3.66; depth 2.66-2.75; D. 11 or 12; A. 9 or 10; scales 5-35 to 
38-5; eye 1 in snout, 3.5 in head, 1.5-2 in interorbital. 

Stout; ventral profile regularly arched, dorsal profile rather steep in front, 
with an angle at the origin of dorsal; preventral area flat, with a median series 
of scales and blunt lateral keels; postventral area with a median and two lateral 
keels converging toward the anal; predorsal area bluntly keeled, with a median 
series of scales. 

Snout broad, subtruncate mouth subterminal, the thin lower jaw included. 

Scales crenate, with two or three diverging striae, nowhere notably increased 
or decreased on the body; caudal lobes densely covered with small scales to 
near their tip; lateral line straight, 

Anterior dorsal and anal rays in the adult prolonged, the former reaching the 
adipose, the latter the caudal; caudal a little more than 3 in the length, ventrals 
not reaching the anus, pectorals not to ventrals. 



EIGEXMAXN: THE FRESHWATER FISHES OF BRITISH GUIANA 263 

Silvery, without definite markings. 

( Jukimatus 29 Oken. 
''Curimates'' Cuvier, Mem. Mus. d'Hist. Nat., I, 1815, 109 (French name only, 

unaccompanied by diagnosis or name of type). 
'•Les Curimates" Cuvier, Regne Animal, II, 1817, 165; ed. 2, II, 1829, 309. 
Curimatus Oken, Isis, 1817, 1183. — Valenciennes, Hist. Nat. Poiss., XX, 1849, 

4, etc. 
Curimata Cloquet, Diet. Hist. Nat., XII, 1818, 240. 
Curimates Goldfuss, Hand. Zool., II, 1820, — . 
Characinus Mindling, Lehrb. Nat. Fische, 1832, 119. 
Cyphocharax Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 297 (spilurus). 
Steindachnerina Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 288 (trachystethus). 
Pcltapleura Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 300 (cyprinoides). 

Type, Salmo edentulus Bloch = Salmo cyprinoides Linnaeus. 

Bell}' rounded or flat, without spines; tongue short and thick, adnate; mouth 

horizontal or slightly oblique; lateral line complete; caudal lobes naked; scales 

large or medium. 

Key to the Guiana Species of Curimatus. 

a. Scales small, 36 or fewer in the lateral line. (Cyphocharax.) 
b. Roof of mouth with few dermal ridges. 

c. A conspicuous black spot at the end of the lateral line spilurus. 

cc. Caudal peduncle plain; lateral line 33-34; dorsal plain microcephalus. 

66. Roof of mouth with numerous flaps, ridges, and papillae; caudal peduncle with a black median line, 
fading out forward. 

d. Dorsal with a large black spot at the base of its middle rays morawhannae. 

dd. Dorsal without black spot '. issororoensis. 

aa. Scales small, 50-62 in the lateral line; at least the scales of the breast with serrate margins. (Curimatus.) 

e. Roof of mouth with numerous folds of skin; upper gill-arches with papilke and with valve-like folds 

at their anterior ends; lower gill-arches with backward and forward directed raker-like filaments 

on their anterior halves, forming a grill on the floor of the mouth, and with a few large papillae 

on their posterior halves schomburgki. 

ee. Roof of mouth with two feeble folds; no gill-rakers; dorsal falcate ciliatus. 

121. Curimatus spilurus Gunther. (Plate XXXIV, fig. 1.) 

"Curucu." 
Curimatus spilurus Gunther, Catalogue, V, 1864, 288 (Essequibo). — Steindach- 
ner, ''Ichthyologische Beitrage," v, 1876, 31 (Hyanuary; lea; Teffe; Rio 
Negro).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 684 (Peruvian Amazon). 

29 Anodus cyprinoides Muller and Troschel, in Schomburgk, Reiscn, III, 1848, 633 (Essequibo, 
Demarara; Rupununi). 



264 MEMOIRS OF THE CARNEGIE MUSEUM 

— Steindachner, "Flussfische Siidamerika's," i, 1879, 5 (Orinoco near Ciudad 

Bolivar). — Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 419 

(19a; Teffe; Jutahy; Cudajas; Jose Fernandez; Lake Hyanuary; Alexo; Ueran- 

duba; Jatuarana; Obidos); Proc. U. S. Nat. Mus., XIV, 1891, 47.— Perugia, 

Ann. Mus. Genova, (2), XVIII, 1897, 24 (Reyes).— Vaillant, Bull. Mus. 

d'Hist. Nat., V, 1899, 155 (Carnot).— Boulenger, Bull. Mus. Zool. ed. Anat. 

Comp. Torino, XV, 1900 (Urucuru). — Eigenmann, Repts. Princeton Univ. 

Exp. Patagonia, III, 1910, 421. 
? Curimata (Cyphocharax) spilura Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 297, 

fig. 4 (Peruvian Amazon). 

Three specimens, 95-100 mm. Mud-flats, Demerara River. (C. M. Cat. 
No. 2089a-6; I. U. Cat. No. 12275.) 

Twenty-two specimens, 70-130 mm. Tukeit. (C. M. Cat. No. 2090a-e; I. U. 
Cat. No. 12276.) 

Two specimens, 112-117 mm. Potaro Landing. (C. M. Cat. No. 2091a; 
I. U. Cat. No. 12277.) 

Nine specimens, 89-101 mm. Tumatumari. (C. M. Cat. No. 1292a-e; I. U. 
Cat, No. 12278.) 

One specimen, 89 mm. Crab Falls. (C. M. Cat. No. 1294.) 

Eight specimens, 35-52 mm., and one 110 mm. Konawaruk. (C. M. Cat. 
No. 1295a-d; I. U. Cat. No. 12279.) 

Nine specimens, 85-120 mm. Below Packeoo Falls. (C. M. Cat, No. 1297a- 
e; I. U. Cat. No. 12281.) 

About two hundred twenty specimens, the largest 60 mm. Rupununi. (CM. 
Cat. No. 2098a-2; I. U. Cat. No. 12282.) 

Fifteen specimens, the largest 50 mm. Gluck Island. (C. M. Cat. No. 2100a- 
j; I. U. Cat. No. 12284.) 

Three hundred twenty-three specimens, the largest 80 mm. Rockstone. 
(C. M. Cat. No. 2101a-2; I. U. Cat. No. 12286.) 

Seventy-eight specimens, the largest 106 mm. Wismar. (C. M. Cat. No. 
2104a-j; I. U. Cat, No. 12288.) 

Abundant. Easily distinguished by its bright caudal spot and by its size. 

Head 4; depth about 3; D. 11 or 12; A. 9; scales 5.5-35-5; eye 1 in snout, 3 
in head, 1.2 in interorbital. 

Elongate, not greatly compressed; preventral area flatfish, with three obscure 
keels; predorsal area bluntly keeled, with or without a regular series of median 
(about nine) scales; snout depressed, the mouth inferior. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 265 

Scales cycloid, crenate on preventral area, with two or three diverging striae; 
lateral line straight, complete; fins naked. 

Fins small; highest dorsal ray about 4 in the length, its origin equidistant 
from snout and end of adipose; caudal a little longer than dorsal; anal emarginate, 
the first ray reaching beyond the tip of the last ray; ventrals reaching vent or 
shorter; pectorals to within three scales of ventrals. 

Highly iridescent, with a variable black spot at end of caudal peduncle. 

122. Curimatus microcephalus Eigenmann and Eigenmann. (Plate XXXIV, 

fig. 2.) 

Curimatus microcephalus Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 

1889, 15 (Surinam); Proc. U. S. Nat. Mus., XIV, 1891, 47.— Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 421. 

Three specimens, 75-124 mm. Tukeit. (C. M. Cat. No. 2106a-6; I. U. Cat. 
No. 12291.) 

Eight specimens, 60-110 mm. Creek below Potaro Landing. (C. M. 
Cat. No. 2107a-d; I. U. Cat. No. 12292.) 

Two specimens, 40-92 mm. Konawaruk. (C. M. Cat. No. 2107a-6.) 

Eight specimens, the largest 55 mm. Amatuk. (C. M. Cat. No. 2108a-d; 
I. U. Cat. No. 12293.) 

Eleven specimens, the largest 105 mm. Kangaruma. (C. M. Cat. No. 
2109a-/; I. U. Cat. No. 12294.) 

Two specimens, 62 mm. Mora Passage. (C. M. Cat. No. 2110a; I. U. 
Cat. No. 12275.) 

Seven specimens, the largest 71 mm. Crab Falls. (C. M. Cat. No. 2118a-d; 
I. U. Cat. No. 12296.) 

Two specimens, 46-56 mm. Wismar. (C. M. Cat. No. 2111a; I. U. Cat. 
No. 12297.) 

Twenty-nine specimens, the largest 90 mm. Erukin. (C. M. Cat. No. 
2U2a-e; I. U. Cat. No. 12298.) 

Sixty-one specimens, the largest 100 mm. Rockstone. (C. M. Cat. No. 
2113a-i; I. U. Cat. No. 12299.) 

Two hundred and fourteen specimens, the largest 125 mm. Tumatumari. 
(C. M. Cat. No. 2114a-z and 2115; I. U. Cat. No. 12300.) 

Head 4; depth 3; D. 11 or 12; A. 9 or 10; scales 5-33 or 34-5; eye 1+ in snout, 
3 in head, 1+ in interorbital. 

Elongate; ventral area rounded, with a median series of scales; predorsal 



266 MEMOIRS OP THE CARNEGIE MUSEUM 

area narrowly rounded, with a median series of about nine scales; snout rounded, 
the mouth inferior. Roof of mouth with a few inconspicuous ridges. 

Scales all cycloid, with two diverging striae; lateral line straight; fins all naked. 

The shape and size of the fins is as in C. spilurus. 

Highly iridescent, the fins brick-red in life. No distinct markings. 

123. Curimatus morawhannae sp. nov. (Plate XXIV, fig. 3.) 
Type, 90 mm. Morawhanna. (Carnegie Mus. Catalog of Fishes No. 2122.) 
Cotypes, fifty-one specimens, the largest 90 mm. Morawhanna. (C. M. 

Cat. No. 212la-i; I. U. Cat. No. 12303.) 

Cotj'pes, three specimens, 48-55 mm. Mora Passage. (C. M. Cat. No. 

2120a-6; I. U. Cat. No. 12302.) 

Very similar to C. microcephalus. Thirty-five or thirty-six scales in the lateral 

line; posterior half of lateral line with a dark streak, most intense toward its end; 

a black spot on the base of the middle dorsal rays; roof of mouth with numerous 

conspicuous flaps, lobes, and papilla?. 

124. Curimatus issororoensis sp. nov. (Plate XXXIV, fig. 4.) 

Type, 104 mm. Issororo Rubber Plantation. (Carnegie Museum Cat- 
alog of Fishes No. 2119.) 

Cotypes, two specimens. Issororo Rubber Plantation. (C. M. Cat. No. 
2123; I. U. Cat. No. 12301.) 

Very similar to C. moraivhannce, but lacking the dorsal spot. 

Head 4; depth 2.8; D. 11; A. 9; scales 5+-36-5. 

125. Curimatus schomburgki Gimther. (Plate XXXV, fig. 1.) 

" Cuticuru." 

Curimatus cyprinoides (? not of Linnseus) Cuvier and Valenciennes, Hist. Nat. 
Poiss., XXII, 1848, 7 (Essequibo). — Muller and Troschel, in Schomburgk, 
Reisen, III, 1848, 633 (Essequibo; Demerara; Rupununi). 

Curimatus schomburgkii Gunther, Catalogue, V, 1864, 291 (British Guiana; Dem- 
erara). — Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 23 
(Surinam); Proc. U. S. Nat. Mus., XIV, 1891, 48.— Fowler, Proc. Acad. 
Nat. Sci. Phila., 1906, 303, fig. 8 (Surinam). — Eigenmann, Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 422. 
So far as known, this species is found in British Guiana and Surinam. It is 

very abundant in quiet waters, especially along the coast. About two hundred 

specimens were preserved. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 



267 



Table of Scales in the Lateral Line of C. schomburgki. 



Locality. 


51 52 53 


54 


55 


56 


57 


58 


59 


GO 


61 


62 


63 


Lama Stop-Off ' 








2 


1 


3 


2 

1 
5 
1 
3 


1 


1 


Maduni Creek . . 




1 




1 

2 


3 
1 
1 
2 

1 




Koreabo 


1 




5 
2 


8 
2 


3 
2 
4 
2 

1 
3 


1 

1 
1 




f 








1 




Issorora 










Morawhanna 












1 


2 




Georgetown 








1 
1 


















2 


3 


3 




2 







Besides the type in the British Museum and the specimens mentioned by 
Miiller and Troschel, and by Cuvier and Valenciennes, I have examined: 

Twenty specimens, 77-215 mm. Wismar. (C. M. Cat. No. 2068a-e; I. 
U. Cat. No. 12256.) 

Twenty-three specimens, 95-260 mm. Lama Stop-Off. (C. M. Cat. No. 
2069a-e; I. U. Cat. No. 12257.) 

Seventy-five specimens, 77-225 mm. Koreabo Rubber Plantation. (C. 
M. Cat. No. 2075a-j; I. U. Cat. No. 12258.) 

Twenty-four specimens, 85-145 mm. Koreabo Rubber Plantation. (C. 
M. Cat. No. 2071a-c; I. U. Cat. No. 12259.) 

Ten specimens, 120-158 mm. Issororo. (C. M. Cat. No. 2072a-e; I. U. 
Cat. No. 12260.) 

Twenty-three specimens, 57-90 mm. Morawhanna. (C. M. Cat. No. 
2073a-?; I. U. Cat. No. 12261.) 

Six specimens, 45-68 mm. Creek in Mora Passage. (C. M. Cat. No. 
2074; I. U. Cat. No. 12269.) 

One specimen, 139 mm. Mud-flats below Wismar. (C. M. Cat, No. 2075.) 

Eight specimens, 96-145 mm. Maduni Creek. (C. M. Cat. No. 207Ga-d; 
I. U. Cat. No. 12262.) 

Three specimens, 187-255 mm. Botanic Garden. (C. M. Cat. No. 20S5a-6; 
I. U. Cat, No. 12271.) 

Four specimens, 54, 59, 187 and 255 mm. Georgetown trenches. (C. M. 
Cat. Nos. 2077a and 2084a; I. U. Cat, Nos. 12270 and 12263.) 

One specimen, 80 mm. Christianburg. (C. M. Cat, No. 2078a.) 

Head 3-3.28; depth 2.25-2.6; D. 11 or 12; A. 10 or 11; scales 13 to 15-54 30 
to 63-8; eye 1 in snout, 3.25 in head, 1-1.6 in interorbital. 

Compressed; dorsal profile high, depressed over the eyes; preventral area flat, 
angulated on the sides, postventral area with a median keel; predorsal area nar- 
rowly rounded, scaled; a triangular adipose area from near the edge of the opercle 

30 In one case 51. 



268 MEMOIRS OF THE CARNEGIE MUSEUM 

to below the nares; premaxillary broad, the mouth inferior, on a level with the 
lower margin of the eye; suborbital narrow. 

Origin of dorsal nearer snout than to caudal, the second and third rays pro- 
longed, reaching in extreme cases to the caudal; caudal deeply forked, the lobes 
longer than the head; pectoral reaching ventrals; anal short, emarginate, the tips 
of the anterior rays reaching base or tip of the last ray; ventrals reaching anal or 
a little shorter. 

Scales regularly increasing in size from the back to the preventral area, where 
they are largest, their margins always ciliated on the preventral area, becoming 
ciliated on other areas with age; a large axillary scale; fins naked; lateral line nearly 
straight, ending in a hastate scale at the base of the caudal. 

Highly iridescent blue above, silvery below, becoming frosted with age; vertical 
fins roseate, shading to yellowish at the base. 

The specimens from Guiana in the Jardin des Plantes are faded and soft, but 
are probably of this species. 

126. Curimatus ciliatus Mtiller and Troschel. 

Anodus ciliatus Muller and Troschel, Horse Ichth., 1845, 25, pi. 4, fig. 4; in 
Schomburgk, Reisen, III, 1848, 633 (Lake Amucu). 

Curimatus ciliatus Castelnau, Anim. Am. Sud, Poiss., 1855, 58 (Amazon).— 
Kner, "Familie der Characinen," i, 1859, 7 (Ypanema; Guapore). — Gunther, 
Catalogue, V, 1864, 292.—? Perugia, Ann. Mus. Genova, (2a), X, 1891, 39 
(Alto Parana). 

Psectrogaster ciliata Eigenmann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 5; 
1891, 46.—? Berg, An. Mus. Nac. Buenos Aires, V, 278 (Coary); Eigen- 
mann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 46 (Descalvados, 
Rio Paraguay). — Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 305 (Ambyiacu 
and Solimoes). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 420. 

Curimatus rutiloides Cope (not of Kner), Proc. Acad. Nat. Sci. Phila., 1871, 258 
(Ambyiacu). 

Curimatus cyprinoides 31 Cope, Proc. Acad. Nat. Sci. Phila., 1871, 291 (Solimoes). 

Curimatus essequibensis Gunther, Catalogue, V, 1864, 291 (Essequibo). — Eigen- 
mann and Eigenmann, Ann. N. Y. Acad. Sci., IV, 1889, 23; Proc. U. S. Nat. 
Mus., XIV, 1891, 48. 

31 The specimen in the British Museum marked cyprinoides has gill-rakers. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 269 

Table of Scales in the Lateral Line of C. ciliatus. 





50 


51 


52 


53 


54 


55 


56 


57 


58 


59 


60 


61 


Rockstone 








3 

1 

3 


1 
1 

1 






1 




1 


1 


( !rab Falls 














Konawaruk 






7 


1 


1 












\\ arraputa 


1 














Rupununi 




2 


1 















(C. M. Cat. No. 2080a-e; I. U. 
(C. M. Cat. No. 2081a-c; I. U. 
(C. M. Cat. No. 2082; I. U. Cat, 
(C. M. Cat. No. 2083a-e; I. U. 



I have examined the type of A. ciliatus in Berlin and that of C. essequibensis in 
London, and: 

Three specimens, 161-170 mm. Rupununi. (C. M. Cat. No. 2079a-&; I. U. 
Cat. No. 12265.) 

Fifteen specimens, 50-72 mm. Rockstone. 
( at, No. 12266.) 

Five specimens, 68-83 mm. Crab Falls. 
Cat, No. 12267.) 

Two specimens, 80-83 mm. Warraputa. 
No. 12268.) 

Sixteen specimens, 68-160 mm. Konawaruk. 
Cat, No. 12272.) 

Head 3 (in the young)-3.4; depth 2.1-2.8 (in the young); D. 11 or 12; A. 
10-12; scales 14 or 15-50 to 61-8 or 9; eyes a little longer than the snout, 3.3 in the 
head, 1.75 in the bony interorbital, (1.25 in the young). 

Elliptical, the ventral profile regularly arched, the dorsal profile but little 
depressed over the head; preventral area obscurely angulated on the sides, post- 
ventral area trenchant, but with a median series of non-spinous scales; predorsal 
line scaled, but without a median series of scales; a well-developed adipose lid; 
mouth terminal, the premaxillary not visible from below; no gill-rakers; palate 
with a feeble dermal ridge on each side; tongue adnate. 

Dorsal small, truncate, the anterior rays scarcely prolonged, but reaching 
beyond the tip of the last, its origin nearly in the middle of the length; caudal 
forked, the lobes a little more than one-fourth of the length; anal emarginate, its 
base oblique; ventrals not reaching anus, pectorals not to ventrals. 

Scales increasing in size from the dorsal to in front of the ventrals, all of them 
strongly serrate; fins naked; axillary scale small. Lateral line straight. 

Air-bladder filiform, reaching to the middle of the anal. 

In the description everything but the formulas is derived from the larger 
specimens. The young fish is much slenderer; the fins are longer, the scales are 
ciliated on the breast, and the dorsal rarely reaches to the adipose. 



270 MEMOIRS OF THE CARNEGIE MUSEUM 

Subfamily Prochilodusle. 
Prochilodus Agassiz. 
Prochilodus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 62. 
Pacu Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pis. 38, 39. 
Chilomyzon Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 309, fig. 11 (steindachneri) . 

Type, Prochilodus argenteus Agassiz. 

Fishes of moderate or large size. Mouth broad, jaws very weak; teeth in- 
serted on lips, movable, in a single series on the sides, in two series in the middle. 
A procumbent dorsal spine; scales rough ctenoid; mouth convertible into a large 
circular sucking disk, not strictly protractile. 

A genus of about twenty-five known species, from the La Plata to Peru, the 
Rio Magdalena, and western Ecuador. One species occurs in the Essequibo, 
and another, closely allied, across the divide, in the upper branches of the Ireng. 

127. Prochilodus rubrotaeniatus Schomburgk. 

Prochilodus rubrotaeniatus Schomburgk, Fishes Brit. Guiana, I, 1841, 258, pi. 28 

(Rios Branco, Negro and Essequibo). — Schomburgk, Reisen, III, 1848, 644 

(Essequibo). — Steindachner, "Fisch-faunadesCauca," etc., 1880, 16 (Cauca). 

— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus.,XIV, 1891,48. — Eigen- 

mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 424. 

Prochilodus nigricans Gunther (not of Agassiz), Catalogue, V, 1864, 295 (Esse- 
quibo). 

One specimen, 303 mm. Tumatumari. (C. M. Cat. No. 2064.) 
Seven specimens, 230-330 mm. Rockstone sand-bank. (C. M. Cat. No. 

2065a-d; I. U. Cat. No. 12254.) 

Head 3.75-3.8; depth 2.45-2.6; D. 12 (counting the last filament); A. usually 

10, sometimes 11, or even 12; scales 7 or 8-45 or 46-6 or 7; eye 1.33-1.5 in snout, 

3.75-4 in head, 2.4 in interorbital. 

Heavy, compressed, deep, subrhomboidal; anterior profile steep, rounded to 

the nape, concave over the eyes; predorsal area bluntly keeled, with a median 

series of about fourteen scales; preventral region broad, angulated at the sides, 

with a median series of slightly keeled scales; postventral region narrowly keeled. 

Head very broad, convex between the eyes; mouth terminal, the lower jaw but very 

slightly shorter than the upper. 

Scales large, rough, denticulate at the margin, very regularly arranged; fins 

naked; a large axillary scale; lateral line straight. 

Fins large; dorsal rounded, sometimes high, the middle ray in No. 2064 being 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 271 

longer than the head; origin of dorsal equidistant from tip of snout and origin of 
adipose; caudal broad, the rays leathery (usually damaged); anal emarginate, the 
second and third rays extending past the tip of the last ; origin of dorsal and ventrals 
about equidistant from tip of snout, reaching over half-way to anal; pectorals 
reaching ventrals, or a little shorter. 

Plumbeous; light streaks extending along the middle of the rows of scales; 
posterior paxt of dorsal and middle of caudal barred; lower fins hyaline to dusky. 

This species was abundant on the sand-bar near Rockstone and was also taken 
in the cataract at Tumatumari. The flesh is soft and specimens are very hard 
to preserve. 

128. Prochilodus maripicru sp. nov. (Plate XXXV, fig. 2.) 

Type, 282 mm. Maripicru Creek. (Carnegie Museum Catalog of Fishes No. 
2066.) 

Cotypes, two specimens, 220-375 mm. Maripicru Creek, a branch of the 
Ireng. (C. M. Cat. No. 1067; I. U. Cat. No. 12255.) 

Head 3.75-4; depth 3; D. 12; A. 10; scales 7 or 8-45-6. Eye 1.75-2 in snout, 
4.5-4.8 in head, 2.5-3 in interorbital. 

Very near to P. rubrotcmiatus, P. argenteus, and P. lineatus, but the head 
narrower, the mouth near]}- a fourth narrower in specimens of equal size, the snout 
more elongate, projecting beyond the lower jaw; origin of dorsal nearer to adipose 
than to snout. 

Color much as in P. rubrotamiatus, but the dark streaks between the rows of 
scales being conspicuous rather than the light band along the rows of scales. 

Subfamily Chilodin^e. 
Tylobronchus 32 gen. nov. 

Fourth gill-arch dilated behind, its surface corrugated. Anal short, emar- 
ginate; a single series of feeble teeth in each jaw, those of the upper jaw bifid, 
three series on the pharyngeals; scales large, serrate; lateral line straight, complete. 
Mouth small, inferior. 

Anterior air-bladder considerably larger than the eye; the posterior long, 
straight, tapering to the origin of the anal, 2.66 in the length. Alimentary canal 
much coiled below the anterior air-bladder, nearly twice the length of the entire 
fish. Vertebrae 15 + 16, without counting those which are coalesced. 

This genus differs from Ccenotropus in having teeth in the lower as well as in 
the upper jaw. 

32 t6\os, a swelling; pp6yxos, throat. 



272 MEMOIRS OF THE CARNEGIE MUSEUM 

129. Tylobronchus maculosus sp. nov. (Plate XXXV, fig. 3.) 

Type, 113 mm. Creek below Potaro Landing. (Carnegie Museum Catalog 
of Fishes No. 1923.) 

Cotype, one specimen, 28 mm. Wismar. (C. M. Cat. No. 1917.) 

Cotype, twenty-one specimens, 47-68 mm. Rockstone. (C. M. Cat. No. 
1918a-e; I. U. Cat. No. 12219.) 

Cotype, one specimen, 104 mm. Crab Falls. (C. M. Cat. No. 1919.) 

Cotypes, fifty-one specimens, 65-107 mm. Tumatumari. (C. M. Cat. No. 
1920a-e; I. U. Cat. No. 12220.) 

Cotypes, nineteen specimens, 97-143 mm. Creek below Potaro Landing. 
(C. M. Cat. No. 1922a-c; I. U. Cat. No. 12221.) 

Cotypes, three specimens, 97-136 mm. Kangaruma. (C. M. Cat. No. 1921a; 
I. U. Cat. No. 12222.) 

This species resembles young Erimyzon sucetta. 

Head 3.66-3.75; depth 3.5; D. 12; A. 9 or 10; scales 4-26 or 27-3; eye 1 in 
snout, 3 in head, 1 in interorbital. 

Heavy, but little compressed, the head very broad; preventral area broad, 
rounded, with a median series of seven scales to between the anterior margins of 
the pectoral; predorsal area broad, with a median series of four or five scales and 
two paired scales near the occiput; occipital process short and broad, reaching 
about one-sixth to the dorsal; interorbital flat, broad; fontanels tapering to above 
the nares; a bridge over the posterior margin of the pupil, another over the anterior 
margin of the eye. 

Cheeks very narrow, covered by the suborbitals; mouth small, the lower jaw 
with a crescentic margin, included, the mouth inferior; lips thick, maxillary slipping 
under the preorbital for its entire length, but not concealed by it, reaching to below 
nares; about nine minute, bifid teeth on each side of the upper jaw; a smaller 
number of conical or truncate teeth on each side of the lower jaw. Lower pharyn- 
geals with three series of bluntly conical teeth, the first series, removed from the 
second, composed of six teeth; the six teeth of the second series much larger, the 
inner one largest; four or five teeth in the last series; tongue adnate, without 
free margin ; mouth without supplemental ridges or valves. 

Gill-rakers short, dendritic, 10 + 14. 

Scales large, with dentate margin, very regularly imbricate; fins naked; a large 
axillary scale; lateral line nearly straight. 

Dorsal large, rounded, its origin about equidistant from nares and origin of 
adipose, its height about 4 in the length; adipose well-developed; caudal deeply 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 273 

forked, the lobes equal, 3.5 in the length; anal emarginate, the highest rays reaching 
considerably beyond the tip of the last ray; origin of ventrals near middle of body, 
not reaching anal by about four scales; pectorals reaching ventrals. 

Straw-color, darker above; a conspicuous black band from tip of snout to end 
of middle caudal rays; each scale above the lateral line with a dark spot at its 
base, or along the middle of the back with a dusky tip; scales between the lateral 
line and ventrals and anal with similar, but smaller, spots; a conspicuous black spot 
on the tip of anterior dorsal rays; fins otherwise hyaline. 

Chilodus Muller and Troschel. 
Chilodus Muller and Troschel, Horse Ichth., I, 1845, 26 (punctatus). 
Camotropus Gunther, Catalogue, V, 1864, 297 (labyrinthicus and punctatus). 

Type, Chilodus punctatus Muller and Troschel. 

Fourth gill-arch dilated behind, its surface corrugated; anal elongate, scarcely 
emarginate; each jaw with a series of feeble, truncate, incisor-like teeth; scales 
large, entire; lateral line straight, complete; mouth small, terminal. 

Alimentary canal about 1.33 times the length of the entire fish. Vertebrae 
12 + 17, not counting the coalesced vertebra?. 

130. Chilodus punctatus Midler and Troschel. (Plate XXXV, fig. 4.) 

Chilodus punctatus Muller and Troschel, Horse Ichth.. I, 1845, 26, pi. 4, fig. 2 
(Lake Amucu, Guiana); in Schomburgk, Reisen, III, 1848, 634 (Swamps in 
savannas). — Kner, "Familie der Characinen," i, 1859, 15. — Eigenmann and 
Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 79. — Eigenmann, Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 424. 

Citharinus chilodus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 103. 

Ccenotropus punctatus Gunther, Catalogue, V, 1864, 297. — Vaillant, Bull. Mus. 
d'Hist. Nat,, V, 1899, 155 (Carnot). 
Eight specimens, 37-60 mm. Rupununi. (C. M. Cat, No. 2205a-c; I. U. Cat. 

No. 12360.) 

One specimen, 56 mm. Konawaruk. (C. M. Cat. No. 1913.) 

One specimen, about 38 mm. Gluck Island. (C. M. Cat, No. 1914.) 

Forty-two specimens, 40-61 mm. Rockstone. (C. M. Cat. No. 1915a-e; 

I. U. Cat, No. 12217.) 

Eleven specimens, 55-82 mm. Crab Falls. (C. M. Cat. No. 1916a-c; I. U. 

Cat, No. 12218.) 

Head 3.66; depth 3; D. 11; A. 12; scales 4-25 to 27-4; eye .75 in snout, 3 

in head, 1 in interorbital. 



274 MEMOIRS OF THE CARNEGIE MUSEUM 

Compressed, back elevated, the profile descending rapidly to the sharp, de- 
pressed snout; preventral area rounded, with about eight median scales to between 
the origin of the pectorals; predorsal area narrowly rounded, with a median series 
of five to seven scales and one or two paired scales near the occiput. Occipital 
process pointed, reaching about one-fourth the distance to the dorsal fin; inter- 
orbital flatfish, grooved; fontanel tapering to above the anterior margin of the 
eye, with a bridge above the posterior margin of the pupil. 

Cheeks narrow, covered by the interorbitals; mouth small, terminal, directed 
obliquely upward; lips medium; maxillary slipping under the preorbital, but not 
concealed by it, reaching to below the nares; each jaw with about twelve (six on 
each side) minute, brown-tipped teeth ; lower pharyngeal teeth in three series, of 
which the anterior series is remote, composed of about six teeth; gill-rakers minute, 
about fourteen on the lower arch. 

Scales large, entire, very regularly imbricate; fins naked, an axillary scale. 
Lateral line straight. 

Dorsal high, rounded, its height about 3 in the length, its origin about equi- 
distant from snout and adipose; adipose well-developed; caudal deeply forked, 
its lobes equal, about 3.5 in the length; anal obliquely truncate, its highest rays 
not reaching base of last ray; ventrals not reaching anal by one or two scales; their 
origin near middle of the length; pectorals reaching ventrals. 

Straw-colored, a dark band from chin to base of middle caudal rays; bases of 
all the scales (except those of the breast) with a dark brown spot ; anal dark ; dorsal 
spotted, the tips of the longest rays dark brown. 

Subfamily Hemiodontinte. 
Parodon Cuvier and Valenciennes. 
Parodon Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 50; pi. 637. 
Type, Parodon subofbitalis Cuvier and Valenciennes. 

Mouth inferior, cutting edge of the pluricuspid teeth of the upper jaw forming 
a straight transverse line; teeth of the lower jaw absent or else confined to the 
sides; no fontanel; gill-membranes united, free from the isthmus. 

131. Parodon bifasciatus sp. nov. (Plate XXXVI, fig. 1.) 
Type unique, 104 mm. Maripicru Creek. (Carnegie Museum Catalog of- 

Fishes No. 1925.) 

Head 5; depth 3.5; D. 11; A. 9; scales 4-38-3 ; eye 1.5 in the snout, 4.5 in the 

head, 2 in the interorbital ; teeth --g^g— 2 . 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 275 

Heavy, tapering rapidly to the conical snout. Lower caudal lobe longer than 
the upper. 

Dark above, lighter below; a black band from snout to end of middle caudal 
rays, a narrower one parallel with it from the occiput to the base of the upper caudal 
rays; a blackish band across the upper part of the anterior dorsal rays. 

Hemiodus Muller. 
Hemiodus Muller, Monatschr. Akad. Wiss. Berlin, Juni, 1842, 324. 
Hemiodopsis Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 318 (microkpis). 

Type, Hemiodus crenidens Muller = Hemiodus unimaculatus (Bloch). 

Teeth in the upper jaw only, pluricuspid, in a horseshoe-shaped series; mouth 
inferior; gill-membranes free from each other and from the isthmus; fontanels 
large; scales below the lateral line of the same size as those above it. 

Key to the Guiana Species of Hemiodus. 
a. Sides with three black cross-bands; a black spot on the caudal peduncle, continued to the end of the lower 

caudal lobe; upper caudal lobe with a weaker "black band quadrimaculatus. 

ua. A black spot on the middle of the sides, half-way between dorsal and adipose, and a black band extending 
from it to the tip of the lower caudal lobe semitaeniatus. 

132. Hemiodus quadrimaculatus Pellegrin. (Plate XXXVI, fig. 2.) 

" Wuranali " of the Wacusi Indians. 

Hemiodus quadrimacidatus Pellegrin, Bull. Mus. d'Hist. Nat., XIV, 1908, 344 

(Camopi R., Fr. Guiana). — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 423. 

One specimen, 110 mm. Tukeit. (C. M. Cat. No. 1926.) 

Three specimens, 55-70 mm. Amatuk. (C. M. Cat. No. 1927; I. U. Cat. 
No. 12187.) 

Thirty-four specimens, the largest 81 mm. Tumatumari, in pools above the 
cataract. (C. M. Cat, No. 1928a-e; I. U. Cat. No. 12188.) 

Six specimens, 57-125 mm. Crab Falls. (C. M. Cat. No. 1929a and 1930; 
I. U. Cat. No. 12189.) 

A conspicuously marked species, evidently closely related to, if not identical 
with, Hemiodus quadrimaculatus Pellegrin. 

Head about 4; depth 4-4.4; D. 12; A. 10; scales 7 or 8-44 to 46-4 or 5. 
Eye 1.3 in snout, 3.3 in head, 1 in interorbital. 

Dorsal and ventral outlines equally arched, the snout pointed, projecting 
considerably; preventral area broad, with a regular median series of scales. 

Twenty to twenty-four teeth in the upper jaw. 



276 MEMOIRS OF THE CARNEGIE MUSEUM 

Dorsal about equal to the length of the head without the opercle, its origin 
equidistant from tip of snout and tip of adipose; caudal deeply forked; anal emar- 
ginate; ventrals not reaching anus by about four scales; pectorals not reaching 
ventrals by about five scales. 

A large axillary scale; fins naked; scales with several vermiculated horizontal 
striae. 

Three black cross-bands, the first half-way between dorsal and tip of occipital 
process, the second from bases of last dorsal rays, and the third in front of the anal; 
each caudal lobe with a black band, the lower one continuous with an elongate 
spot on the caudal peduncle. 

133. Hemiodus semitaeniatus Kner. (Plate XXXVI, fig. 3.) 
Hemiodus semihmiatus Kner, "Familie der Characinen," i, 1859, 18, pi. 4, fig. 7 

(Rio Guapore). — Gunther, Catalogue, V, 1864, 299. — Eigenmann and Eigen- 

mann, Proc. U. S. Nat. Mus., XIV, 1891, 49.— Boulenger, Trans. Zool. Soc. 

London, XIV, 1896, 34 (San Luis, Matto Grosso). — Eigenmann, Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 423. 

Seven specimens, 75-86 mm. Konawaruk. (C. M. Cat. Nos. 1931, 1932; I. 
U. Cat, No. 12190.) 

One specimen. Gluck Island. (C. M. Cat, No. 1945.) 

Very closely allied to H. gracilis Gunther. 

Head 4.3-4.5; depth 4-4.25 (5.6 in the type of gracilis); D. 11; A. 9-11; 
scales 7-44 or 45-4. Eye 1 in snout, 3.2 in head, 1+ in interorbital. 

Slender; dorsal and ventral profiles equally curved; predorsal and preventral 
area with regular median series of scales. Snout projecting the width of the upper 
lip; about twenty-four teeth in the upper jaw. 

Height of dorsal nearly equal to the length of the head, its origin equidistant 
from tip of snout and tip of adipose; anal short, very slightly emarginate, the 
longest ray projecting but little beyond the tip of the last ray; caudal deeply forked; 
ventrals not reaching anus by about four scales; pectorals not to ventrals by about 
seven scales. 

A large axillary scale; fins naked; each scale with several horizontal striae. 

Iridescent silvery; an oval black spot on the middle of the sides half-way be- 
tween the dorsals, a conspicuous black band along the inner margin of the lower 
caudal lobe, tapering forward to the lateral spot; anal and upper caudal lobe 
peppered; peppered bands (evident only with a lens) across the sides in front of 
the dorsal, across the region of the lateral spot, and across the caudal peduncle; 
dorsal and tips of caudal lobes pink in life. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 277 

The types of H. gracilis from the River Cupai, 800 miles from the sea, are 
much slenderer. 

Anisitsia Eigenmann. 
Anisitsia Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1903, 144. 

Type, Anodus notatus Schomburgk. 

Similar to Anodus, but the scales increasing in size and decreasing in number 
from the lateral line downward. 

134. Anisitsia notata (Schomburgk). 
Anodus notatus Schomburgk, Fishes Brit. Guiana, I, 1842, 218, pi. 15 (Rio 

Negro) . 
Hemiodus notatus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

119, pi. 638. — Castelnau, Anim. Am. Sud, Poiss., 1855, 64 (Paraguay). — ■ 

Kner, "Familie der Characinen," i, 1859, 22 (Guapore). — Gunther, Cat- 
alogue, V, 1864, 298 (Essequibo; Surinam). — Steindachner, "Flussfische 

Sudamerika's," ii, 1881, 40 (Rio Trombetas; Rio Guapore). — Eigenmann 

and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 49. 
Anisitsia notata Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

423. 
Hemiodus unimaculatus (not of Bloch) Muller and Troschel, in Schomburgk, 

Reisen, III, 1848, 633 (Essequibo); Hora? Ichth., Ill, 1849, 9. 
Hemiodus microcephalia Gunther, Catalogue, V, 1864, 298 (River Capin). — 

Eigenmann and Eigenmann, Proc. U. S. Nat. Mus. XIV, 1891, 49. 

Ten specimens, 80-112 mm. Christianburg. (C. M. Cat. No. 1933o-6; 
I. U. Cat. No. 12191.) 

Three specimens, 64-80 mm. Kumaka. (C. M. Cat. No. 1934a; I. U. Cat. 
No. 12200.) 

Sixteen specimens, 74-89 mm. Malali. (C. M. Cat. No. 1935a-c; I. U. 
Cat, No. 12192.) 

Eighteen specimens, 71-111 mm. Bartica, rocks. (C. M. Cat. No. 1936a-e; 
I. U. Cat. No. 12193.) 

Two specimens, about 190 and 195 mm. Bartica, rocks. (C. M. Cat. No. 
1937a; I. U. Cat. No. 12194.) 

Twenty-seven specimens, 58-95 mm. Wismar. (C. M. Cat. No. 1939a-e; 
I. U. Cat. No. 12195.) 

Five specimens, 91-112 mm. Crab Falls. (C. M. Cat. No. 1940a-6; I. U. 
Cat, No. 12196.) 



278 MEMOIRS OF THE CARNEGIE MUSEUM 

Fifteen specimens, 75-100 mm. Mud-flats below Wismar. (C. M. Cat. No. 
1941a-e; I. U. Cat. No. 12197.) 

Nineteen specimens, 57-85 mm. Lama Stop-Off. (C. M. Cat. No. 1924a-e; 
I. U. Cat, No. 12198.) 

Two specimens, 69-72 mm. Cluck Island. (C. M. Cat. No. 1943a; I. U. 
Cat, No. 12199.) 

Thirteen specimens, 65-200 mm. Rockstone. (C. M. Cat, No. 1944a-c; 
I. U. Cat, No. 12201.) 

Head 4-4.25; depth 3.5-4.5; D. 11 or 12; A. 11; scales 11 to 13-55 to 64-5. 
Eye 1 in snout, 3.25 in head, 1.1 in interorbital, with little difference in different 
sizes. 

Resembling the Cisco of American lakes. Somewhat compressed, the dorsal 
and ventral profiles equally arched; the ventral surface broad, with a large median 
series of scales before the ventrals; predorsal area keeled, with a median series of 
scales from the dorsal to near the occipital process. Occipital process reaching 
one-seventh the distance to the dorsal; frontal fontanel reaching to above the nares. 

Upper jaw considerably projecting; twenty-eight to thirty teeth in the upper 
jaw. Gill-rakers twenty-six to forty-eight, the longest about one-sixth the length of 
the eye. 

Dorsal pointed, about equal to the length of the head, its origin equidistant from 
tip of snout and tip of adipose ; caudal deeply forked ; anal emarginate, the highest 
ray not reaching the tip of the last; ventrals not reaching anus by about four 
scales; pectorals not to ventrals by about four scales. 

Scales with many vermiculated horizontal stria?; lateral line straight; fins 
naked, a large axillary scale; exposed edge of the scales of the middle series on the 
breast four times as wide as the exposed edge of the scales below the dorsal, the 
scales becoming larger on the second series of scales below the lateral line. 

Highly iridescent, coppery below, steel-blue above; each caudal lobe with a 
black band, the lower one more intense ; a circular or oval lateral spot the center 
of which is over the thirtieth to thirty-third scale; under the lens the caudal 
peduncle, a downward band in front of dorsal, and the anal are sometimes peppered. 

Subfamily Pyrrhulinin^e. 

Pyrrhulina Cuvier and Valenciennes. 

Pyrrhulina Cuvier and Valenciennes, Hist, Nat. Poiss., XIX, 1846, 535, 

pi. 589. 
Holotaxis Cope, Proc. Am. Philos. Soc, XI, 1870, 563. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 279 

Type, Pyrrhulina filamemtosa Cuvier and Valenciennes. 

Small fishes. Premaxillary and dentary with two or more series of conical 
teeth; mouth very oblique. 

135. Pyrrhulina filamentosa ( uvicr and Valenciennes. 
Pyrrhulina filamentosa Cuvier and Valenciennes, Hist. Nat. Poiss., XIX, 1846, 

535 (Surinam). — Gunther, Catalogue, V, 1864, 286 (Essequibo). — Stein- 

dachner, SB. Akad. Wiss. Wien, LXXII, 1875, — (Cayenne). — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 428. 

This species is very abundant in all brooks. Judging from the size, it reaches 
its highest development some distance from the coast. 

Thirty-five specimens, 38-86 mm. Aruataima. (C. M. Cat. No. 1893a-e; 
I. U. Cat. No. 12171.) 

One hundred specimens, 36-106 mm. Holmia Creek. (C. M. Cat. No. 
1894a-m; I. U. Cat, No. 12172.) 

Fifty specimens, 29-85 mm. Savannah Landing. (C. M. Cat. No. 1895a-e; 
I. U. Cat. No. 12173.) 

Four specimens, 36-40 mm. Two hours below Holmia. (C. M. Cat. No. 
1896a-6; I. U. Cat. No. 12205.) 

Seven specimens, 40-57 mm. Tukeit. (C. M. Cat. No. 1897a-6; I. U. Cat. 
No. 12174.) 

Two specimens, 38-53 mm. Erukin. (C. M. Cat. No. 1898a; I. U. Cat. No. 
12175.) 

Two specimens, 38-54 mm. Konawaruk. (C. M. Cat, No. 1899a; I. U. Cat. 
No. 12176.) 

One specimen, 53 mm. to base of caudal. Wismar. (C. M. Cat. No. 1900a.) 

Seventy-five specimens, 21-84 mm. Christianburg Canal and small pools. 
(C. M. Cat. No. 1901a-.,; I. U. Cat. No. 12177.) 

Two specimens, 41-55 mm. Rockstone. (C. M. Cat. No. 1902a; I. U. Cat. 
No. 12178.) 

Twenty-two specimens, 39-57 mm. Gluck Island. (C. M. Cat, No. 1903a-e; 
I. U. Cat, No. 12179.) 

Fourteen specimens, 64-96 mm. Nickaparoo. (C. M. Cat. No. 1904a-e; 
I. U. Cat. No. 12180.) 

Twenty-nine specimens, 40-115 mm. Kumaka. (C. M. Cat. No. 1905a-e; 
I. U. Cat. No. 12181.) 

Two specimens, 47 mm. Georgetown trenches. (C. M. Cat. No. 1906a; I. U. 
Cat, No. 12182.) 



280 MEMOIRS OF THE CARNEGIE MUSEUM 

Forty-one specimens, 33-62 mm. Cane Grove Corner. (C. M. Cat. No. 
1907«-6; I. IT. Cat. No. 12183.) 

Five specimens, 37-46 mm. Maduni Creek. (C. M. Cat. No. 1908o-5; I. U. 
Cat. No. 12206.) 

One hundred and twenty specimens, 27-75 mm. Lama Stop-Off. (C. M. 
Cat. No. 1924a-z; I. U. Cat. No. 12184.) 

One specimen, about 70 mm. Barima River. (C. M. Cat. No. 1909a.) 

Thirteen specimens, 54-69 mm. Issorora Rubber Plantation. (C. M. Cat. 
No. 1910o-e; I. U. Cat. No. 12185.) 

One specimen, 58 mm. Creek in Mora Passage. (C. M. Cat. No. 4911a.) 

One hundred and twenty-six specimens, the largest 30 mm. Aruka River. 
(C. M. Cat, No. 1912a-z; I. U. Cat. No. 12186.) 

Head 4.5-4.66; depth 4.5-5; D. 10; A. 12; scales 22-29 in a longitudinal 
series, 5.5 between dorsal and ventral. Eye 1 in snout, 3.5 in head, 1.5 in inter- 
orbital. 

Slender; head broad, flat, scaled to above preopercle; mouth oblique, pre- 
maxillaries meeting at an angle; conical teeth along the margin of the maxillary, 
increasing in size toward the upper angle; two widely separated series of teeth on 
the premaxillary and the dentary; gill-rakers short and slender. 

Scales with radiating stria? ; axillary scale small, rounded, the series of scales 
along the anal bent upward to form a basal sheath; a few irregular scales at the 
base of the caudal lobes. 

Dorsal short and rounded, its height 4.5 to 5 in the length, or lanceolate, the 
middle rays prolonged in some specimens, one-third of the entire length. Upper 
caudal lobe much the longer, variable in size, when longest 2.5 in the length; anal 
rounded, or the middle rays prolonged, 5 or 6 in the length; ventrals not to the 
anus, or beyond the origin of the anal; pectorals not to the ventrals. 

Fins in specimens from Holmia light geranium-red; caudal yellow; lateral band 
of the head continued in red on the body. Sides olive-green, with rusty spots. 

In the Gluck Island specimens the dorsal is red in front and below, adipose 
brick-red, caudal greenish yellow, anal orange in front, greenish behind; ventrals 
and pectorals yellowish, rows of rusty spots in front on lower part of sides. A 
black band from the chin to the eyes or the opercle, or to a few scales beyond; 
dorsal with a round black spot to nearly entirely black; anal and ventrals some- 
times narrowly margined with black; frequently a dusky predorsal line. 

The Kumaka specimens were olive-green with rusty spots, the anal and ventrals 
margined with dark. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 281 

This species — if all the above specimens represent one species — differs greatly 
in different localities. Specimens from the Guiana plateau, for instance, have a 
dusky blotch above the pectoral, those in the lowlands do not. Some have the 
dark band extended to the eye, others to the edge of the opercle, and still others 
to a short distance behind the opercle. The fins also differ very greatly. A final 
decision cannot be given as to the identity of the specimens on account of the 
difference in size in examples coming from different places. 

Subfamily Nannostomatin^e. 
Nannostomus Gunther. 
Nannostomus Gunther, Proc. Zool. Soc. London, 1872, 146. 

Type, Nannostomus beckfordi Gunther. 

Skull truncate; no occipital process; no fontanel, no lateral line; no adipose 
fin; jaws equal; teeth broad at top, with several points of equal length. Minute 
fishes. 

136. Nannostomus beckfordi Gunther. 
Nannostomus beckfordii Gunther, Proc. Zool. Soc. London, 1872, 146 (Gottver- 

wagting Plantation, a short distance east of Georgetown). — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Head 3.6; depth 4.25; D. 8; A. 10; lateral line 22; transverse line 5 between 
dorsal and ventral. 

Body compressed. Eye one-third of the length of the head, and a little longer 
than the snout. Origin of the dorsal and ventral fins in the middle of the length 
(without caudal). A silvery band along the middle of the side, bordered above 
by a reddish, and below by a blackish band. A black spot on the lower half of the 
gill-cover. Caudal fin red. 

Total length 30 mm. 

This species is readily distinguished by the dark spot on the lower half of the 
opercle. 

137. Nannostomus marginatus Eigenmann. (Plate XXXVI, fig. 4.) 
Nannostomus marginatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 41. 

Type, 26 mm. Maduni Creek. (Carnegie Museum Catalog of Fishes No. 
1171.) 

Cotypes, ten specimens, 21-25 mm. Maduni Creek. (C. M. Cat. No. 1172a-d; 
I. U. Cat. No. 11696.) 

Cotypes, five specimens, 19-24 mm. Lama Stop-Off. (C. M. Cat. No. 
U73a-b; I. U. Cat. No. 11697.) 



282 MEMOIRS OF THE CARNEGIE MUSEUM 

Cotypes, two specimens, 22-23 mm. Crab Falls. (C. M. Cat. No. 1174a; 
I. U. Cat, No. 11698.) 

Cotypes. two specimens, 24 mm. Rockstone sand-bank. (C. M. Cat. No. 
1175a; I. U. Cat. No. 11699.) 

Cotypes, five specimens, 25-31 mm. Gluck Island. (C. M. Cat. No. 1176a-b; 
I. IT. Cat. No. 11700.) 

Cotypes, two specimens, 27-31 mm. Christianburg canal ? (C. M. Cat. No. 
1177a; I. U. Cat, No. 11701.) 

Cotypes, nineteen specimens, 21-22 mm. Cane Grove Corner. (C. M. Cat, 
No. 1178a-/; I. U. Cat, No. 11702.) 

Most nearly related to N. trifasciatus Steindachner. 

Head 3.6; depth 3.4; D. 10; A. 11 or 12; five scales between dorsal and ventral, 
nine or ten before the dorsal, twenty-one in a median lateral series. Eye 3 in the 
head; snout 4 in the head; interorbital equal to the eye. 

Short and chubby, the snout especially short, the jaws equal. Origin of the 
dorsal over the insertion of the ventrals; pectorals reaching a little more than half- 
way to the ventrals; ventrals half-way to middle of anal. No adipose fin. 

Back chocolate, the median line darkest; three black lateral stripes, a median 
golden stripe and a golden stripe shading to silvery ventrad; belly white. A crim- 
son spot on the middle of the dorsal and of the ventral fins; a crimson streak 
bordering the upper margin of the middle black band from above middle of the 
pectoral to middle of the dorsal; caudal suffused with orange; anal posteriorly 
orange-red; iris red above. 

The upper two black bands converge on the caudal fin, the middle one extends 
from the end of the snout and mandible to base of the lower caudal lobe, the lowest 
extends from near the mouth along the suborbital, below the pectoral to the anal, 
and is continued upon the anterior rays of the anal and sometimes margins the rest 
of the fin. Anterior dorsal ray, or rays, dark. 

138. Nannostomus minimus Eigenmann. (Plate XXXVI, fig. 5.) 
Ncmnostomus minimus Eigenmann, Ann. Carnegie Mus., VI, 1909, 41; Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 21 mm. Erukin. (Carnegie Museum Catalog of Fishes No. 1165.) 
Cotypes, two specimens, 20 and 21 mm. Erukin. (I. U. Cat. No. 11691.) 
Cotype, one specimen, 22 mm. Amatuk. (C. M. Cat. No. 1166a.) 
Head 3.6; depth 4.66; D. 9; A. 10; seven scales in front of dorsal, five between 
dorsal and ventrals, twenty-one in a lateral series. Eye greater than snout, 3 in 
the head ; interorbital equal to the eye. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 283 

Origin of dorsal over origin of ventrals; pectorals reaching half-way to middle 
of ventrals; ventrals to anal; origin of anal on a vertical from middle of last dorsal 
ray. No adipose fin. 

Back uniform gray, median darker line wanting; a light band from end of 
snout to upper part of middle of caudal; a black band from end of mandible to 
lower part of middle of caudal; darkest above pectorals and above middle of 
ventrals; a few chromatophorcs along base and in front of the anal fin; fins mostly 
hyaline, their chromatophores few. 

139. Nannostomus simplex Eigenmann. (Plate XXXVI, fig. 6.) 
? Nannostomus anomalum Steindachner, " Ichthyologische Beitrage," v, 1876, 81 

(Rio Negro; Amazon at Obidos). 
Nannostomus simplex Eigenmann, Ann. Carnegie Mus., VI, 1909, 42; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 25 mm. Lama Stop-Off. (Carnegie Museum Catalog of Fishes No. 
1167.) 

Cotype, 29 mm. Lama Stop-Off. (I. U. Cat, No. 11692.) 

Closeh T allied to N. auratus and N. minimus. 

Head 3.5; depth 4.5; D. 10; A. 10; five scales between dorsal and ventral, nine 
before dorsal, twenty-four in a lateral series. Eye a little greater than snout, 3 in 
the head, equal to the interorbital. 

Pectorals reaching half-way to second third of the ventrals, ventrals half-way 
to tip of last anal ray; origin of anal under tip of last dorsal ray. No adipose fin. 

Back dark gray with a median dark line; a light band from snout to base of 
upper rays of middle of caudal; a black band through mandibles and snout to 
base of lower caudal, and continued on the two middle rays; ventral surface plain, 
except for a spot between the tips of the ventrals; chromatophores of the lateral 
band scattered above the pectorals and above the front part of the anal. 

Pcecilobrycon Eigenmann. 
PoEcilobrycon Eigenmann, Ann. Carnegie Mus., VI, 1909, 43. 

Type, Pwcilobrycon harrisoni Eigenmann. 

Skull truncate, without a crest; no fontanel; no lateral line; pectorals normal; 
teeth broad-tipped, five-pointed. 

Key to the Guiana Species of Pcecilobrycon. 
a. A single dark band from chin to near end of middle caudal ray, alight band above it; back chocolate. 

harrisoni. 
aa. A median dorsal and three lateral dark bands trifasciatus. 



284 MEMOIRS OF THE CARNEGIE MUSEUM 

nun. Like limrisnin, the chocolate of the back bordered by a darker line, a dark streak from behind the base 

of the lower pectoral rays to and along base of the anal erythrurus. 

imiiii. A dark band from snout to and including the lower caudal lobe; an oblique ocellated spot above the 
middle of the caudal ocellarus. 

140. Pcecilobrycon harrisoni Eigenmann. (Plate XXXVII, fig. 1.) 
Pcecilobrycon harrisoni Eigenmann, Ann. Carnegie Mus., VI, 1909, 43; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 55 mm. Canal at Christianburg. (Carnegie Museum Catalog of Fishes 
No. 1160.) 

Cotypes, two specimens, 45-51 mm. Canal at Christianburg. (I. U. Cat. 
No. 11709.) 

Head 4; depth 5.25; D. 9; A. 10; five scales between dorsal and ventral, 
twenty-six or twenty-seven in a median series, eleven or twelve in front of the 
dorsal; eye 3 in the head; upper jaw projecting. Snout very little greater than 
eye; interorbital a little less than eye. 

Adipose well-developed, behind tip of anal; origin of dorsal slightly posterior 
to that of the ventrals. Pectorals reaching half-way to ventrals; ventrals slightly 
more than half-way to anal 

Back chocolate; a broad straw-colored band from tip of snout to middle of 
upper caudal lobe; a narrow black band from tip of mandible through eye along 
lower part of peduncle to near tip of shortest caudal ray, and a few rays inferior to 
it. Ventral surface silvery, dotted from midway of the ventrals to the anal, the 
dots continued over the lateral band above the anal. A spot on either side of 
snout, the iris dorsad, a line along base of anal, and a streak above and below 
the caudal band, crimson. An oblique, dotted bar across the yellow lateral band 
just above tip of pectoral. Last anal rays dark. 

Similar to P. unifasciatus, in which the color from the dark lateral bands across 
the back is uniform, i. e., lacking the straw-colored band above the dark band. 

Named for Mr. J. B. Harrison, M.A., C.M.G., F.G.S., Government Geologist, 
Georgetown, British Guiana, who assisted the expedition in various ways. 

141. Pcecilobrycon trifasciatus (Steindachner). (Plate XXXVII, fig. 2.) 
Nannostomus trifasciatus Steindachner, " Ichthyologische Beitrage," v, 1876, 75, 
pi. 9, fig. 2 (Lagunas of the Amazon near Barra do Rio Negro; Rio Negro; 
Tabatinga). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 
1891, 49. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 427. 
Pcecilobrycon auratus Eigenmann, Ann. Carnegie Mus., VI, 1909, 44; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 427. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 285 

Seventeen specimens, 27-34 mm. Konawaruk. (C. M. Cat. Nos. 1161a 
(type of P.. auratus) and 1162a-d; I. U. Cat. Xo. 11688.) 

Three specimens, 27 mm. Rockstone sand-bank. (C. M. Cat. No. 1163a; 
I. U. Cat. No. 11689.) 

Eight specimens, 25-33 mm. Gluek Island. (C. M. Cat. No. 1664a-6; I. U. 
Cat. No. 11690.) 

Head 3.75; depth nearly 5; D. 10; A. 11; five scales between dorsal and ven- 
tral, twenty-three along a median series, ten in front of dorsal. 

Eye 3 in head, a little less than snout, greater than interorbital; upper jaw 
projecting. 

Adipose fin over about middle of last anal ray; dorsal beginning behind the 
vertical from the origin of the ventrals. Pectorals reaching half-way to middle of 
ventrals, ventrals half-way to base of last anal ray. 

Mid-dorsal line from head to adipose chocolate, on either side of which is a 
straw-colored stripe, confluent with a median line on the head to the tip of the snout. 
A similar chocolate stripe on the sides, bounded below by another straw-colored 
stripe, both concurrent with the back; ventrad of the last is a chocolate band, widest 
above tips of pectorals, reaching the vanishing point above the eye and below the 
tip of the dorsal; a golden band from upper part of eye to upper caudal lobe, con- 
tinued forward of eye as a red streak; a dark brown lateral band from tip of jaws 
to tip of lower caudal lobe; a horizontal streak below the eye. Some scales below 
the lateral band with a brown spot; two oblique, black cross-bands, one up and 
back from last half of pectorals, the other up from before anal. Lower caudal lobe 
black; base of upper caudal lobe and of anal red; anal blackish. Fins otherwise 
hyaline. 

142. Pcecilobrycon erythrurus Eigenmann. (Plate XXXVII, fig. 3.) 
Pcecilobrycon erythrurus Eigenmann, Ann. Carnegie Mus., VI, 1909, 44; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 33 mm. Rockstone sand-bank. (Carnegie Museum Catalog of Fishes 
No. 1168.) 

Cotypes, seven specimens, 33-37 mm. Rockstone sand-bank. (C. M. Cat. 
No. 1168a-fe; I. U. Cat. No. 11693.) 

Cotypes, four specimens, 22-27 mm. Cluck Island. (C. M. Cat, No. 1170a; 
I. U. Cat, No. 11694.) 

Cotype, one specimen, 22 mm. Amatuk. (C. M. Cat. No. 1187a.) 

Cotypes, two specimens, 32-33 mm. Rupununi Pan. (C. M. Cat. No. 1188a; 
I. U. Cat. No. 11695.) 



286 MEMOIRS OF THE CARNEGIE MUSEUM 

Allied to P. trifasciatus. 

Head 3.75; depth 4.66-4.75; D. 10; A. 9 or 10; five scales between dorsal and 
ventral, ten before dorsal, twenty-six in a median line. Eye equal to snout and to 
interorbital, 3.2 in the head; jaws equal. 

Dorsal over the vertical from the ventrals; pectorals reaching half-way to 
middle of ventrals; ventrals half-way to middle of anal; adipose fin a little anterior 
to the tip of the last anal ray; origin of anal on a vertical from the tip of the last 
dorsal raj'. 

Back light brown, margined by a more or less faint darker line; a light streak ' 
from snout through top of iris to upper half of middle of caudal; a conspicuous 
lateral black band from mandible to base of lower caudal lobe, continued on the rays 
just below the middle; a dark streak from behind the base of the lower pectoral 
rays to and along base of the anal ; middle anal rays dusky. Ventral surface silvery. 

In life a blood-red streak borders the superior margin of the black lateral band 
over the middle of the pectorals; a red spot on basal half of the dorsal, two red 
spots on base of the caudal, one similar spot on the anal lobe; an orange spot on 
each ventral fin. 

143. Pcecilobrycon ocellatus Eigenmann. (Plate XXXVII, fig. 4.) 
Pcecilobrycon ocellatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 45; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 41 mm. Wismar. (Carnegie Museum Catalog of Fishes Xo. 1179.) 

Cotypes, two specimens, 39-41 mm. Wismar. (I. U. Cat. Xo. 11703.) 

Cotypes, seventy-one specimens, 35-43 mm. Rockstone sand-bank. (C. M. 
Cat. Xo. 1181a-./; I. U. Cat. Xo. 11704.) 

Cotypes, nine specimens, 33-42 mm. Cluck Island. (C. M. Cat. Xo. 
1181a-c; I. U. Cat, Xo. 11705). 

Cotypes, eight specimens, 31.5-37 mm. Rupununi Pan. (C. M. Cat, Xo. 
118a-c; I. U. Cat. Xo. 11706.) 

Cotype, one specimen, 39 mm. Crab Falls. (C. M. Cat. Xo. 1183a.) 

Cotypes, two specimens, 39-42 mm. Tumatumari. (C. M. Cat, Xo. 1184a; 
I. U. Cat, Xo. 11707.) 

Cotypes, eighteen specimens, 31-43 mm. Konawaruk. (C. M. Cat. Xo. 
1185a-e; I. U. Cat. Xo. 11708.) 

Most nearly related to P. unifasciatus Steindachncr. 

Head 4.2-4.4; depth 5.4-5.5; D. 10; A. 10 or 11; five scales between dorsal 
and ventral, ten before dorsal, twenty-eight along a lateral series. Eye a little 
shorter than snout, 3.3 in the head, equal to the interorbital. Upper jaw projecting. 



EIGENMANN - . THE FRESHWATER FISHES OF BRITISH GUIANA 287 

Dorsal inserted slightly behind the vertical from the insertion of the ventral; 
pectorals reaching half-way to second third of ventrals; ventrals half-way to base 
of last anal ray; adipose fin over middle of last anal ray. 

Light brown above, bordered below by a black band from tip of snout and 
mandible to the end of the lower caudal lobe; the band is widest on the caudal 
peduncle, where it unites with its fellow of the other side; a bar connects the two 
lateral bands in front of the anal. Lower parts silvery white. Dorsal hyaline; 
lower caudal lobe black, obliquely crossed near the center by a red band, and mar- 
gined with red above; usually a black ocellus-like spot or streak near the middle 
of the caudal rays near the center of the fin; middle, and sometimes the posterior 
anal rays, dark. Opercle purple. 

Archicheir Eigenmann. 
Archicheir Eigenmann, Ann. Carnegie Mus., VI, 1909, 46. 

This genus is a Nannostomas with peculiar pectorals. In Nannostomus the 
pectorals are normal, as in related genera; in this genus they appear to have retained 
the embryonic structure. They are broad, dermal flaps, with hair-like fringes. 

Gill-membranes united, free from the isthmus. 

144. Archicheir minutus Eigenmann. (Plate XXXVII, fig. 5.) 
Archicheir minutus Eigenmann, Ann. Carnegie Mus., VI, 1909, 46; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 428. 

Type unique, 26 mm. Canal at Christianburg. (Carnegie Museum Catalog 
of Fishes No. 1186.) 

This species is readily recognizable by the color of the caudal and anal fins. 

Head 3.5; depth 5.66; D. 9; A. 11; scales large. Eye 3.5 in the head, con- 
siderably greater than the interorbital, but little shorter than the snout. 

Origin of dorsal a little posterior to origin of ventrals. Adipose fin considerably 
behind tip of the anal. 

Back chocolate. A light band from end of snout to base of superior caudal 
lobe; a dark band from end of maxillary to the base of the inferior caudal lobe. 
A black spot at base of the pectoral, and one before the first ventral ray. Dorsal 
dusky; adipose black. Middle caudal rays black; an oblique bar from the edge 
of base of each lobe to the end of the median black bar, the lowermost one much the 
widest, the superior bar brown, shading into black at both ends. Anal hyaline, 
a black bar across tips of its last rays. 

It is very probable that the pectoral fin in this specimen is abnormal, and that 
the genus is a synonym of Poecilobrycun. 



288 MEMOJRS OF THE CARNEGIE museum 

Characidium Reinhardt. 

Characidium Reinhardt, Overs. Dan. Vidensk. Selsk. Forh., 1866, 56, pi. 2, figs. 

1 and 2. 
Chorimycterus Cope, Am. Nat., XXVIII, 1894, 67 (tenuis). 
Nannocharax Boulenger, Boll. Mus. Zool. ed. Anat. Comp. Torino, X, 1895, 2 

(borellii) . 
Poecilosomatops Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 323, fig. 17 (etheostoma) . 

Type, Characidium fasciatum Reinhardt. 

Premaxillary and dentary each with a single series of conical or three-pointed 
teeth; no frontal fontanel, a small circular occipital fontanel; a triangular occipital 
process; adipose fin present; lateral line complete. Small or minute fishes of the 
sand-bars and cataracts, living among the rocks or burrowing in the sand, much as 
do the Etheostomatine fishes of North America. 

Key to the Guiana Species of Characidium. 
a. Tips of outer pectoral rays thickened; color well-developed. (Inhabitants of rocky places and creeks.) 

6. A broad lateral band, not crossed by dark bars laterale. 

bb. Lateral band crossed by vertical bars. 

c. Pectorals not reaching ventrals; about four lateral bands or streaks, crossed by about eight 

bars vintoni. 

cc. Nearly uniform blue-black; dorsal, caudal and ventrals conspicuously barred with white and 

black blennioides. 

ccc. Straw-color, with a narrow black band from tip of snout to base of middle caudal rays, and about 

ten brown cross-bands fasciatum. 

on. Tips of outer pectoral rays not thickened; pellucid. (On sand-bars, burrowing.) 

d. Middle of sides with twenty-seven to thirty chromatophores, one or more out of line; back with about 

sixteen cross-bars pellucidum. 

dd. Sides with numerous crescents of brown; back with about thirteen cross-bars pteroides. 

ddd. About ten dark brown cross-bars, most intense on back and along the lateral line, the centers of 
the scales in the bars colorless catenatum. 

145. Characidium laterale Eigenmann. (Plate XXXVII, figs. 6, 7.) 

Characidium laterale Eigenmann, Ann. Carnegie Mus., VI, 1909, 36; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 427. 

Type, 37 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1141.) 

Cotypes, three specimens, 29-35 mm. Amatuk. (I. U. Cat. No. 11673.) 

A Zygonectes-like Characidium. 

Head 3.75-4; depth 6; D. 11 or 12; A. 8; scales 4-36-2. 

Eye equal to snout, 3.75 in head. Teeth three-pointed. Pectoral reaching 
ventrals, its outer rays thickened; ventrals three-fourths to anal; fourth anal ray 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 289 

reaching considerably beyond tip of last, but not to the caudal fulcra. Base of 
dorsal reaching half-way to middle of adipose, about 7 in the length. 

A broad band from tip of snout to base of middle caudal rays, bordered by a 
light streak above; back brown, with darker cross-shades; a small spot just above 
base of first ventral ray; a dark spot or streak on the chin, another anterior to the 
anal; a dark spot on either side of base of anal, ventral surface otherwise plain. 
A dark spot anterior to the dorsal and one in front of the adipose fin. Fins 
without definite markings. 

146. Characidium vintoni Eigenmann. (Plate XXXVIII, figs. 1, 2.) 

"Tunatruic." 

Characidium vintoni Eigenmann, Ann. Carnegie Mus., VI, 1909, 36; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 428. 

Type, 76 mm. Shrimp ('reek, where the path from Tukeit to the Kaieteur 
crosses it. (Carnegie Museum Catalogue of Fishes No. 1142.) 

Cotypes, fifty-two specimens, 53-82 mm. Shrimp Creek. (C. M. Cat. No. 
114Sa-j; I. U. Cat, No. 11674.) 

Named for Mrs. C. Vinton, one of the few ladies who have visited the habitat 
of this species. 

Resembling Hadropterys. 

Head 4-4.25; depth 5.4-6; D. 11; A. 8; scales 4-37-2^, nine median scales 
anterior to dorsal; eye 1.66 in the snout, 4.6 in the head, about 1 in the interorbital; 
bony interorbital equal to half the diameter „of eye; teeth obscurely three-pointed. 

Snout long, pointed. Pectorals with the tips of the outer rays thickened, not 
reaching ventrals ; ventrals not to anal ; highest anal ray equal to length of caudal 
peduncle, not reaching the fulcra of the caudal ; third dorsal ray reaching tip of last; 
base of dorsal equal to one-half its distance from the adipose fin, about 8 in the 
length; tip of third dorsal ray reaching much beyond tip of the last ray. 

A conspicuous band from the tip of the snout to the middle of the caudal, 
bordered above by an interrupted yellowish band about half its width ; a dark band 
along the middle of the back, another between it and the lateral band; a dark streak 
parallel to the lateral band below it in front of the caudal peduncle. About eight 
bands across the back to the lateral band, sometimes continued below the lateral 
band directly, or with a shift backward or forward. Lower surface silvery ; opercle, 
angle of preopercle, and a band below the eye sometimes dark ; axil and spot above 
origin of ventrals and a streak along base of anal dark; lower surface of chin pale 
or dark. All these markings sometimes obscured by increased pigmentation. 



290 MEMOIRS OF THE CARNEGIE MUSEUM 

Dorsal nearly uniform. Caudal lobes with an oblique black bar; area between this 
bar and the basal spot of the middle rays pigmentless, faintly dusky posterior to the 
black bars. Tips of outer rays of pectoral and ventral and the first rays of the anal 
swollen, these fins hyaline, except for a few color-cells along the middle of the middle 
rays. 

147. Characidium blennioides Eigenmann. (Plate XXXVIII, figs. 3, 4.) 
Characidinm. blennioides Eigenmann, Ann. Carnegie Mus., VI, 1906, 27; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 428. 

Type, 52 mm. Erukin. (Carnegie Museum Catalog of Fishes No. 1144.) 

Cotypes, six specimens, 43-52 mm. Erukin. (C. M. Cat. No. 1145a-6;I.U. 
Cat. No. 11675.) 

Cotype, one specimen, 55 mm. Tukeit. (C. M. Cat. No. 1146a.) 

Cotypes, two specimens. 42-54 mm. Creek above Potaro Landing. (C. M. 
Cat. No. 1147a; I. U. Cat. No. 11676.) 

Cotypes, five specimens, 43-49 mm. Tumatumari. (C. M. Cat, No. 1148a-6; 
I. U. Cat. No. 11677.) 

Cotypes, twelve specimens, 33-47 mm. Crab Falls. (C. M. Cat. No. 
1149a-6; I. U. Cat. No. 11678.) 

Cotypes, thirteen specimens, 31-60 mm. Amatuk. (C. M. Cat, No. 1150a-d; 
I. U. Cat. No. 11679.) 

Resembling Etheostoma coeruleum. 

Head 3.75-4; depth 4.5-4.75; D. 11; A. 8; scales 4-32 to 34-2; seven median 
scales anterior to the dorsal; eye 1.1 in snout, 3.75 in head; bony interorbital 
half the diameter of eye. Teeth three-pointed, the middle point longest. 

Pectorals with the tips of the outer rays thickened, reaching ventrals; ventrals 
to anal; third anal ray reaching fulcra of the caudal, but scarcely beyond the tip 
of the last ray. Base of dorsal about 1.2 in its distance from the adipose fin, 5.5 
in the length; third dorsal ray reaching base of the last. 

Adult nearly uniform bluish black, the ventral surface being but little lighter. 
Margin of adipose and caudal, and outer edges of ventrals and pectorals, white. 
Dorsal, caudal, anal, and ventrals conspicuously barred with white and black. 
Pectorals, exclusive of the tips of the outer four rays, bluish black. 

Younger specimens and lighter colored ones show about seven cross-bands and 
more or less incomplete rows of light spots following the rows of scales. A dark 
band forward from eye; a narrower one downward. In the youngest specimen 
from Amatuk the pectoral, like the ventral and anal, has four dark bands. 33 

33 A smaller specimen from this place, 23 mm. long, has a single band on the pectorals and the ventrals. 
It is crushed and I am not certain of its identification. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 291 

148. Characidium fasciatum Reinhardt. (Plate XXXIX, figs. 1, 2.) 
Characidium fasciatum Reinhardt, Overs. Dan. Vidensk. Sclsk. Forh., 1866,56, 
pi. 2, figs. 1, 2 (Rio das Velhas). — Lutken, Dan. Vidensk. -Helsk. Skr., (5), 
XII, 1875, 194, figs. 1.2; and p. xi (Rio das Velhas). — Steindachner, "Siiss- 
wasserfische Siidostlichen Brasilien," iii, 1876, 1 (Rio Parahyba; Rio Pia- 
banha near Petropolis); "Flussfische Si'idamerika's," i, 1879, 7 (Orinoco 
near Ciudad Bolivar); " Ichthyologische Beitrage," ix, 1882, 19 (Canelos, 
Ecuador). — Boulenger, Proc. Zool. Soc. London, 1887, 280 (Sarayacu).— 
Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 50. — Eigen- 
mann and Norris, Rev. Mus. Paulista, IV, 1900, 357 (Rio Tiete; Barba- 
tana). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 427. 
Characidium zebra Eigenmann, Ann. Carnegie Mus., VI, 1909, 38; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 428. 

Seven specimens,. 47-55 mm. Maripicru. (C. M. Cat. Nos. 1151 and 1152a-b; 
I. U. Cat. No. 11680.) (Types of C. zebra.) 

Fourteen specimens, 32-44 mm. Maripicru? (C. M. Cat. No. 1159; I. U. 
Cat. No. 11687.) (Types of C. zebra.) 

Head 4.25-4.5; depth 5-5.3; D. 11; A. 7 or 8; scales 4-35 or 36-3^; nine 
scales before the dorsal. Eye equal to snout, 3.75^1 in the head; bony inter- 
orbital 1.3-1.5 in the eye. Teeth three-pointed, the middle point longest. 

Pectorals with the tips of the outer rays thickened, reaching ventrals; ventrals 
not to anal; highest anal raj' a little less than the length of the caudal peduncle, 
reaching a little beyond tip of of the last ray, but not to caudal fulcra; base of 
dorsal fin reaching over half-way to the adipose, 6 in the length, the third ray 
extending about half-way to tip of last. 

Straw-color; a narrow black band from tip of snout to base of middle caudal 
rays, where it ends near a small black spot; about ten brown cross-bands, the fifth 
encircling the entire body at tips of ventrals in the type; these bands sometimes 
becoming double along the sides, giving the appearance of many narrow bands. 
Back dusky, the centers of the scales light. Opercle and lower lip dark. Ventral 
surface colorless. Dorsal with a spot behind and near the base of each ray, begin- 
ning with the fourth; chromatophores along the branched part of the rays; other 
fins hyaline, without distinct markings. 

149. Characidium pellucidum Eigenmann. (Plate XXXIX, figs. 3-5.) 

Characidium 'pellucidum Eigenmann, Ann. Carnegie Mus., VII, 1910, 39; Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 428. 



I 



292 MEMOIRS OF THE CARNEGIE MUSEUM 

Type, 39 mm. Gluck Island. (Carnegie Museum Catalog of Fishes No. 
1156.) 

Cotype, 37 mm. Gluck Island. (I. U. Cat. No. 11683.) 

Resembling Ammocrypta pellucida. 

Head 4.33; depth 7; D. 11; A. 8; scales 3-36-2, nine in front of dorsal. Eye 
a little longer than snout, 3.75 in head; bony interorbital a little less than half 
the length of head. Teeth with three large points. 

Pectorals reaching vcntrals, the outer rays not thickened; ventrals not to 
anal ; anal rounded, the third ray reaching a little beyond tip of last, but not nearly 
to caudal; dorsal truncate the third ray reaching a little beyond middle of last; 
base of dorsal 6.75 in the length, equal to one-half its distance from tip of adipose. 

Pellucid in life. Middle of sides with twenty-seven to thirty stellate chromato- 
phores, one or more of which may have slipped up or down from the line of the 
rest; a few smaller cells dorsad of the lateral series; back with about sixteen cross- 
bars, which do not encroach on the sides. A dark band forward from eye to end 
of snout. Upper part of cheek and opercle each with a chromatophore; top of 
head with a few chromatophores; ventral parts clear, except for a patch of chromato- 
phores between the pectorals, one between the ventrals, and a patch at origin of 
anal; a dark median line between tip of ventral and another behind the anal 
fin. A dark band about two-thirds up on the dorsal and one across base of the 
anterior raj's, both very faint; caudal with a few faint dark spots; fins otherwise 
hyaline. 

150. Characidium pteroides Eigenmann. (Plate XXXIX, figs. 6, 7.) 

Characidium pteroides Eigenmann, Ann. Carnegie Mus., VI, 1909, 40; Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 428. 
Type, 28 mm. Konawaruk. (Carnegie Museum Catalog of Fishes No. 

1157.) 

( 'otypes, two specimens, 25-27 mm. Konawaruk. (I. U. Cat. No. 116S4.) 
Cotype, one specimen, 23 mm. Rockstone. (C. M. Cat. No. 1158.) 
Cotype, one specimen, 24 mm. Wismar. (I. U. Cat. No. 11685.) 
A characin which burrows in the sand, very similar to C. pellucidum. 
Head 4; depth 6; D. 11; A. 7; scales 4-36-2. Eye considerably longer than 

snout, a little over 3 in the head; teeth three-pointed. 

Pectorals about reaching ventrals, the tips of their outer rays not thickened ; 

ventrals not nearly to anal; anal rounded, not nearly reaching the caudal fulcra. 

Third dorsal ray reaching about to second third of the last; base of dorsal 1.3 in 

its distance from the adipose, 6 in the length. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 293 

Hyaline. Sides with numerous crescents of brown; back with about thirteen 
cross-bars made up of crescents; in places two opposing crescents form ocelli. A 
dark band from eye to end of snout; a black bar through the opercle; a deep- 
seated spot on angle of preopercle; a streak, sometimes broken, backward from eye; 
an interrupted black line along the ventral surface, concentrated between the 
ventrals and in front of the anal. Faint markings on dorsal, caudal, and anal; 
fins otherwise hyaline. 

151. Characidium catenatum Eigenmann. (Plate XXXVIII, figs. 5, 6.) 

Characidium catenatum Eigenmann, Ann. Carnegie Mus., VI, 1909, 40; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 428. 

Type, 38 mm. Warraputa. (Carnegie Museum Catalog of Fishes No. 1153.) 

Cotypes, twelve specimens, 32-35 mm. Rockstone sand-bank. (C. M. Cat. 
No. 1154a-d; I. U. Cat No. 11681.) 

Cotypes, two specimens, 37-38 mm. Crab Falls. (C. M. Cat. No. 1155a; 
I. U. Cat. No. 11682.) 

A sand-burrowing characin, resembling Ammocrypta pellucida. It stands 
alone among the species from Guiana in having single-pointed, strictly conical 
teeth, approaching in this respect Pyrrhulinus. 

Head 4-4.2; depth 6-6.2; D. 10 or 11; A. 8; scales 4-38-3, ten before the dorsal. 
Eye a little longer than snout, 3.3 in head; bony interorbital about 2 in eye. 
Teeth conical. 

Pectorals reaching ventrals or not, the tips of the outer rays not thickened; 
ventrals not to anal; anal rounded, the fifth ray highest, reaching slightly beyond 
tip of last, not nearly to caudal; dorsal low, subtruncate, the third ray not quite 
reaching tip of last; base of dorsal extending half-way to tip of adipose, 7.75 in the 
length. 

Pellucid in life. Sides of head and body more or less iridescent; a dark stripe 
from eye to end of snout; about ten dark brown cross-bars, most intense on back 
and along the lateral line; the centers of the scales of the bars colorless, giving each 
band a chain-like appearance ; a few chromatophores on the margins of other dorsal 
scales. A minute, round black spot at base of caudal, surrounded by a hyaline 
area, which is bounded posteriorly by a faint color-halo; fins otherwise all hyaline. 
A blackish median line from behind ventrals to the vent. 



294 MEMOIRS OF THE CARNEGIE MUSEUM 

Subfamily Anostomatin.e. 

Anostomus Gronow. 

Anostomus Gronow, Mus. Ichth., II, 1754, 13, pi. 7, fig. 2.— Scopoli, Intr. Hist. 

Nat., 1777. 
Pithecocharax Fowler, Proc. Acad. Nat, Sci. Phila., 1906, 320. 
Type, Sahno anostomus Linnaeus. 

Small to medium-sized fishes, with the snout subcircular in cross-section; the 
mouth minute, vertical; the lips thick, plicate; about eight teeth in each jaw, bifid 
or multilobed incisors; the gill-membrane united with the isthmus. 

Key to the Guiana Species of Anostomus. 
a. Dark brown, with two conspicuous light bands: one from mouth along upper margin of eye to upper caudal 
lobe, one along lower margin of eye to lower caudal lobe; a fainter band from the nape to behind the 
dorsal on either side of the median line, a similar one from below pectoral to anal, and another along 

the midventral line. Brilliant in life anostomus. 

aa. Sides with spots. 

6. A black spot below the dorsal, and another at the base of the middle caudal rays, sometimes another 
on the fourth scale of the lateral line; each scale of the lower part of the sides with a median dark 
brown streak. Backs of small, light-colored individuals with about fifteen wavy cross-bands, 
which may be obscured. Origin of dorsal nearer snout than to base of caudal; preorbital and 

postorbital portion of head about equal trimaculatus. 

66. Spots as under b, an additional one above anterior part of anal; cross-bands broader; scales of the 
upper part of the sides with an iridescent spot. Origin of dorsal equidistant from tip of snout 
and base of middle caudal rays. Snout longer than postorbital portion of head plicatus. 

152. Anostomus anostomus (Linnaeus). (Plates XL and XLI, fig. 1.) 

Anostomus Gronow, Mus. Ichth., II, 1754, 13, pi. 7, fig. 2. 

Salmo anostomus Linnaeus, Syst. Nat., ed. 10, 1, 1758, 312, No. 24; ed. 12, 1, 1866, 
514.— Gmelin, Syst. Nat,, L hi, 1788, 1387, No. 29. 

Leporinus anostomus Cuvier and Valenciennes, Hist, Nat. Poiss., XXII, 1848, 38. 

Anostomus anostomus Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 
1891, 50. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia. Ill, 1910, 
425. 

Anostomus salmoneus Gronow, Cat, Fish, ed. Gray, 1854, 153. — Gunther, Cata- 
logue, V, 1864, 303 (Essequibo). — ? Steindachner, "Flussfische Stida- 
merika's," ii, 1881, 40 (Jutahy).— Garman, Bull. Essex Inst,, XXII, 1890, 17. 
Nine specimens, 55-94 mm. Crab Falls. (C. M. Cat, No. 1852a-6; I. U. 

Cat. No. 12140.) 

Eight specimens, 64-95 mm. Tumatumari, above and below the fall. (CM. 

Cat. No. 1853a-Z>; I. U. Cat, No. 12141.) 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 295 

Four specimens, 84-107 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1854a; I. 17. Cat, No. 12142.) 

One specimen, 90 mm. Kangaruma. (C. M. Cat, No. 1855a.) 

Eight specimens, 65-122 mm. Erukin. (C. M. Cat. No. 1856a-&; I. U. Cat, 
No. 12143.) 

Two specimens, 54-70 mm. Amatuk. (C. M. Cat, No. 1857a; I. U. Cat. 
No. 12144.) 

Head 4-4.4; depth 4.5-5; D. 12; A. 10; scales 4-39 or 40-3.5. Eye 4 in 
head, 1.5 in snout, 1.4-1.75 in interorbital. 

Slender; dorsal and ventral outlines about equally curved, the width 1.75 in 
the depth; snout subcircular in section, turned upward slightly; mouth vertical, 
the margin of the upper lip sloping backward slightly. A frontal fontanel extending 
to above middle of the eye, the parietal fontanel obliterated, but the bones not united 
in a specimen 115 mm. long. Four teeth in each premaxillary, the outermost one 
four-lobed, the rest three-lobed; four teeth in each dentary, the outermost one 
three-lobed, the middle ones bifid. 

Dorsal rounded, its highest ray 5.5 in the length, its origin nearer tip of adipose 
than to snout; caudal deeply forked, the lobes nearly equal, about 4 in the length; 
anal emarginate, the tip of the first ray reaching beyond the tip of the last; ventrals 
reaching about half-way to anal; pectorals not quite half-way to middle of ventrals. 

Dark brown, with four light lateral bands, dull yellow in life, of which the two 
median bands are much the most conspicuous, one reddish from the mouth to the 
eve, which it margins dorsad, continuing to the upper caudal lobe, and one along 
the lower margin of the eye to the lower caudal lobe ; of the less conspicuous bands 
one begins at the middle of the eye, running along the first row of scales from the 
median dorsal series, the other begins below the pectoral and extends to the anal. 
There is a midventral yellowish stripe. Dorsal and caudal intense translucent 
crimson, fading out toward the tips of the fins; indefinite spots of the same color 
on the anal and ventrals. 

The color differs much in brilliancy and intensity in different individuals. 

153. Anostomus trimaculatus (Kner). (Plate XLI, fig. 2.) 

Schizodon trimaculatus Kner, "Familie der Characinen," i, 1859, 25, pi. 6, fig. 12 
(Matto Grosso).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 690 (Peruvian 
Amazon). 

Anostomus trimaculatus Gunther, Catalogue, V, 1864, 304. — Garman, Bull. Essex 
Inst., XXII, 1890, 17 (Gurupa). — Eigenmann and Eigenmann, Proc. U. S. 



296 MEMOIRS OF THE CARNEGIE MUSEUM 

Nat. Mus., XIV, 1891, 50— Pellegrin, Bull. Mus. d'Hist, Nat., V, 1899, 406 
(Manaos). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
425. 
Pithecocharax trimaculatus Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 320 (Peru- 
vian Amazon). 

Two specimens, 116-124 mm. Twoca Pan. (C. M. Cat. No. 1858; I. U. 
Cat, No. 12145.) 

Three specimens, 67 to about 111 mm. Crab Falls. (C. M. Cat. No. 1859; 
I. U. Cat. No. 12146.) 

One specimen, 72 mm. Rockstone. (C. M. Cat, No. 1860.) 
Head 4-4.5; depth 3.7-4; D. 12; A. 10 or 11; scales 5-42 to 44-4.5; eye 3.6 
in head, 1.25 in snout, 2 in interorbital; 3.2, 1.2, and 1.25, respectively, in a small 
specimen. 

Comparatively heavy, the width equal to half the depth; profile sharply 
depressed from the nape to the snout; snout comparatively short, subelliptical in 
cross-section, the interorbital broad; opercle striate. 

Four teeth on each side of each jaw, the outer tooth of the lower jaw four- 
pointed, the next three-pointed, the inner bifid; those of the upper jaw all three- 
pointed. 

Dorsal rounded, its longest ray 5 in the head, its origin nearer tip of adipose 
than to snout; caudal deeply forked, the upper lobe longest, 3.5 in the length; 
anal truncate, the tips of all the rays reaching the same point when depressed; 
ventrals reaching half-way or a little more than half-way to anal; pectorals about 
half-way to middle of anal. 

Light or dark brown. A large, subcircular, faintly ocellated spot on the 
middle of the sides below the posterior half of the dorsal; a similar, but smaller, 
spot at the base of the middle caudal rays; sometimes a small spot on the front 
scales of the lateral line; opercle dark; each scale of the lower part of the sides 
with a dark spot or streak, the spots forming series; light-colored specimens with 
five dark wavy lines across the back in front of the dorsal, and about ten similar ones 
under and behind the dorsal, becoming broader and diffuse toward the caudal. 
Fins reddish in life. 

154. Anostomus plicatus sp. nov. (Plate XLI, fig. 3.) 
Type, 86 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1861.) 
Cotypes, two specimens, 77-89 mm. Crab Falls. (I. U. Cat. No. 12148.) 
Cotypes, two specimens, 102-104 mm. Bartica. (C. M. Cat, No. 1862a; I. 
U. Cat, No. 12149.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 297 

Cotypes, two specimens, 72-77 mm. Amatuk. (C. M. Cat. No. 1S63«; I. U. 
Cat. No. 12150.) 

Cotypes, two specimens, 78-90 mm. Tumatumari. (C. M. Cat. No. 1864a; 
I. U. Cat. No. 12151.) 

Very similar to A. trimaculatus, but the snout longer and slenderer, the 
lips more prominent, and the color different. 

Head 3.4-3.5; depth 3.3-4; D. 12; A. 10; scales 5-39 or 40-4. Eye 1.75 in 
snout, 4 in head, 1.5 in interorbital ; 1.5, 3.5, 1.1, respectively, in a specimen 77 
mm. long. 

Width about half the depth; dorsal profile convex to the nape, thence very 
concave to the very prominent lips; snout subcircular in cross-section, much longer 
than the post-orbital part of the head; opercle faintly striate in the largest. 

Four teeth on each side of each jaw; the two lateral teeth of the lower jaw 
tricuspid, the middle ones truncate; the two outer ones of the upper jaw tricuspid, 
the middle ones bifid, the two points frequently unequal. 

Dorsal rounded, its highest ray 5.75-6 in the length; its origin equidistant 
from tip of snout and base of middle caudal rays; caudal deeply forked, its upper 
lobe about 4 in the length; anal slightly emarginate, the longest ray reaching the 
tip of the last; ventrals reaching about half-way to middle of anal, pectorals more 
than half-way to ventrals. 

Light brown to nearly black; four spots along middle of sides, the first on 
and below the fourth scale of the lateral line, the second from the fifteenth or 
seventeenth scale, the third on the twenty-sixth and twenty-seventh, the last at 
the end of the line. About twelve cross-bars, not evident on dark individuals, the 
part of the bars below the lateral line shifted forward or backward. Iridescent 
spots on the scales. 

Schizodon Agassiz. 
Schizodon Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 66, pi. 36. 

Type, Curimatus fascial us Spix. 

Like Anostomus, but with the mouth terminal, the snout not produced, elliptical 
in cross-section; lower teeth short and broad. 

155. Schizodon fasciatus (Spix). 

Curimatus fasciatus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pi. 36. 

Schizodon fasciatus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 66. — Schom- 
burgk, Fishes Brit. Guiana, I, 1841, 252, pi. 26 (Rio Branco) .— Muller and 
Troschel, Horae Ichth., I, 1845, 10, pi. 1, figs. 5-5a; in Schomburgk, Reisen, 



298 MEMOIRS OF THE CARNEGIE MUSEUM 

III, 1848, 634 (Rupununi; Takutu; Rio Branco). — Kner, "Familie der 
Characinen," i, 1859, 23 (Rio Negro and Cujaba). — Cope, Proc. Am. Philos. 
Soc, XI, 1870, 566 (Para); XVII, 1878, 689 (Peruvian Amazon; Para; Amby- 
iacu). — Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907, 7 
(Para; Bolivar). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 425. 
Anostomus fasciatus Gunther, Catalogue, V, 1864, 304 (British Guiana; Caracas). 
— Steindachner, "Flussfische Slidamerika's," iv, 1882, 12 (Huallaga).— 
Cope, Proc. Acad. Nat. Sci. Phila., 1871, 258 (Ambyiacu). — Garman, Bull. 
Essex Inst., XXII, 1890, 21 (Coary; Dutch Guiana; Hyamary; lea; Jose 
Fernandez; Jutahy; Lakes Alexo, Hyavary, Saraca, Manacapurii, Manaos; 
Obidos; Rio Puty; Sao Paolo; Serpa; Tabatinga; Teffe; Tonantins; Villa 
Bella). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 50. 
— ? Perugia, Ann. Mus. Genova, (2 a), X, 1891, 40 (Candelaria.) — Pellegrin, 
Bull. Mus. d'Hist. Nat., V, 1899, 406 (Manaos). 
One specimen, 141 mm. Rupununi Pan. (C. M. Cat. No. 1865a.) 
Two specimens, 168-174 mm. Twoca Pan. (C. M. Cat. No. 1866a; I. U. 
Cat. No. 12147.) 

Head 4.66; depth 4; D. 12; A. 10 or 11; scales 4 or 4.5-43 or 44-4; eye 1.25 
in snout, 3.5 in head, 2 in interorbital. 

Elongate, the width a little more than half the depth. Dorsal and ventral 
profiles nearly equally arched; a just perceptible or no depression over the eyes; 
head broad, the mouth very small, terminal, its width equal to the eye; a regular 
median series of scales in front of the dorsal and along the midventral line. 

Four multicuspid, black-tipped, graduated teeth on each jaw, those of the upper 
jaw forming an open crescent. 

Dorsal obliquely rounded, its longest ray 4.33 in the length, its origin equi- 
distant from tip of snout and origin of adipose. Caudal deeply forked, the upper 
lobe 4.5 in the length; anal squarely truncate when open, the tip of the first rays 
reaching far beyond the tip of the last when closed; ventrals reaching half-way 
to anal; pectorals about half-way to second third of ventrals. 

Dark above, white or yellow below. Opercle dark; a series of four dark cross- 
bands and a small spot at the base of the middle caudal rays; lower caudal lobe 
margined with dark. 

Schizodontopsis Garman. 
Sckizodontopsis Garman, Bull. Essex Inst., XXII, 1890, 16 (tceniatus) . 

An Anostomatine genus with the mouth small, very obliquely directed upward; 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 299 

upper jaw with eight teeth in a crescent, the middle ones broad, bilobed, or squarely 
truncate in the adult, the lateral ones rapidly smaller, obscurely trilobed; lower 
jaw with similar teeth, more distinctly directed forward, much as in Leporinus; 
gill-membrane joined to the isthmus; postventral area with an obscure median 
keel; preventral area in the adult with a median and two lateral keels or angles, 
the preventral surface to the base of the pectoral being covered with three series of 
scales. 

In the young the teeth of the upper jaw have several points, and the ventral 
keels are not evident; the gill-membrane may also form a narrow free fold across 
the isthmus in the young. 

156. Schizodontopsis laticeps sp. nov. (Plate XLI, fig. 4.) 
Type, 264 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1825.) 
Cotypes, two specimens, 96-240 mm. Crab Falls. (I. U. Cat. No. 12116.) 
A fourth small specimen of this species was taken by Mr. Ellis on Gluck Island. 
Head 4.2; depth 3-3.16 (4 in young); D. 12 or 13; A. 11 or 12; scales 6-42-4 
or 5; eye 1.25 in snout, 3.3-3.5 in head, 2 in interorbital in the adult. 

Heavy, the width not quite half the depth; profile arched, comparatively strep, 
with a slight depression over the eyes; belly with a blunt median keel; two similar 
lateral keels in front of the ventrals; predorsal region rounded; head broad, some- 
what depressed, its width at the anterior margin of the eye equal to its depth at 
the same point; interorbital convex; width of mouth greater than the length of 
the orbit; mouth oblique, the lower jaw projecting. 

The teeth of the upper jaw graduated, the middle ones broad-lobed incisors, ar- 
ranged in a crescent; teeth of the lower jaw similar to those of the upper. 

Dorsal subtruncatc, rounded in the young, its highest ray about 4.5 in the 
length; its origin a trifle nearer snout than to tip of adipose; caudal broad, leathery 
in the adult, the upper lobe not greatly longer than the lower, about 4.5 in the 
length (4 in the young) ; anal truncate, the first rays not reaching tip of last, not 
reaching caudal; ventrals not reaching half-way to anal (just half-way in the 
young); pectorals more than half-way to middle of ventrals. 

Ashy gray; a broad obscure band from the dorsal, narrowing to the ventrals; 
a narrower cross-shade above middle of pectorals and in front of anal; adipose, 
anal and axil dark. Young with a black band from the chin to the eye and middle 
of caudal. 

Leporinus Spix. 
Leporinus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 65 (novemfasciatum) . 
Abramites Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 331 {hypselonotus). 



300 MEMOIRS OF THE CARNEGIE MUSEUM 

Type, Leporinus novemfasciatus Spix. 

Head small, conical, the mouth minute, with a few (four to six) teeth in each jaw, 
directed obliquely forward toward the middle, obliquely truncate or lobed; gill- 
openings joined to the isthmus. 

The members of the genus are abundant about the rocks and cataracts, and 
are difficult to catch in the usual ways. 

Key to the Guiana Species of Leporinus. 
a. A median lateral band reaching from the gill-opening to the caudal, another curving from the eye downward 

and back to the lower edge of the caudal arcus. 

aa. An incomplete lateral band or series of median spots. 

6. Lateral band beginning under the dorsal and extending to the caudal ; lower sides plain. . . nigrotaeniatus. 
66. Sides with a median series of spots. 

c. First spot most conspicuous, under the dorsal; two spots behind it obscurely connected by a 
stripe in the young; sometimes one or both of the latter absent ; lateral line 38-40* . . friderici. 
cc. Spots as under c, but with other spots below, above and in front of them; lateral line 33-34. 

d. Mouth inferior; three teeth in each side of each jaw maculatus. 

dd. Mouth terminal; four teeth in each side of each jaw granti. 

aaa. Sides with vertical bands. 

e. Sides with seven bands, four broad ones and three narrower ones in the interspaces alternus. 

ee. Sides with ten bands in the adult, united in pairs in the young, conspicuous in the young, becoming 
indefinite with age fasciatus. 

157. Leporinus arcus sp. nov. (Plate XLII, fig. 3.) 
"Tumany" of the Indians. 
Type, 206 mm. Tukeit. (Carnegie Museum Catalog of Fishes No. 1832.) 
Cotypes, two specimens, 397-400 mm. Tukeit, (C. M. Cat. No. 2296; I. U. 

Cat, No. 12122.) 

Three specimens, 64-104 mm. Creek below Potaro Landing. (C. M. Cat. 

No. 1829a; I. U. Cat. No. 12119.) 

One specimen, 49 mm. Tumatumari. (C. M. Cat, No. 1830a.) 

One specimen, 50 mm. Locality ? (I. U. Cat. No. 12120.) 

Two specimens, 59-102 mm. Amatuk. (C. M. Cat. No. 1831a; I. U. Cat, 

No. 12121.) 

Head 3.5-4; depth 3+ ; D. 12; A. 10 or 11; scales 4-36 or 37-4; eye 2.5 

in snout, 5.5 in head, 3 in interorbital in the largest; 1 in snout, 3 in head, 1.25 in 

interorbital in a specimen 64 mm. long. 

Robust, the width a little more than half the length in the adult. Predorsal 

and preventral areas broadly rounded. Snout conical; interorbital very convex 

* In the young of friderici the " spots " appear as a band in process of breaking up into spots. Mrs. 
C. H. Eigenmann. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 301 

in the adult; mouth terminal in the young, slightly oblique, becoming subterminal 
or inferior with age. Four teeth on each side of each jaw. 

Origin of dorsal equidistant from snout and base of upper caudal lobe in the 
young, farther forward in adult; margin of dorsal rounded, the highest ray about 
5 in the length; upper caudal lobe but little longer than lower, 3.33-3.5 in the 
length; anal emarginate, not reaching caudal ; ventrals reaching half-way to origin 
or end of base of anal; pectorals a little more than half-way to middle of ventrals. 

A conspicuous, straight, dark chocolate band from upper part of gill-opening 
to base of middle caudal rays, as deep as the eye or deeper; a narrower, similarly 
colored band arched from the eye downward and back along the lower margin of 
the caudal peduncle to the caudal ; a similar one curving upward slightly from above 
the gill-opening to the adipose, bordered above by a faintly lighter area; the middle 
of the back and base of last anal rays dark. A dark spot at base of pectorals. 

Tips of fins, bases of scales in the light areas of the sides, opercles, and cheeks 
rosy or red in the adult. Light parts white to straw-color; gill-covers greenish 
yellow; in the young the bases of all the fins are sometimes rusty. 

158. Leporinus nigrotseniatus (Schomburgk). (Plate XLII, figs. 1, 2.) 

Chalceus nigrotceniatus Schomburgk, Fishes Brit. Guiana, I, 1841, 213, pi. 13, fig. 
2 (Rio Negro). 

Leporinus nigrotceniatus Muller and Troschel. Horse Ichth., I, 1845, 11, pi. 1, 
fig. 7; in Schomburgk, Reisen, III, 1848, 634 (Pomeroon). — Cuvier and 
Valenciennes, Hist. Nat. Poiss., XXII, 1848, 32 (Pedrero on the Rio Negro). 
— Kner, "Familie der Characinen," i, 1859, 34 (Barra do Rio Negro; Rio 
Branco).— Gunther, Catalogue, V, 1864, 309 (Essequibo). — Steindachner, 
" Ichthyologische Beitrage," v, 1876, 62 (middle course of the Amazon).— 
Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 51. — Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 426. 

Leporinus margaritaceus u Gunther, Catalogue, V, 1864, 309 (Brit. Guiana). 

Six specimens, 120-207 mm. Tumatumari. (C. M. Cat. No. 1820«; I. U. 

Cat, No. 12112.) 

One specimen, 145 mm. Rockstone. (C. M. Cat. No. 1821.) 

31 Type, 177 mm. to the base of the middle caudal rays. British Museum. British Guiana, Schom- 
burgk. 

Head 4.66; depth 5.16; D. 12; A. 10; scales 5.5-40-5. Eye 1.5 in snout, 3.8 in head, 1.6 in interorbital. 

Resembling nigrotwniatus in shape; dorsal 5 in the length, its origin equidistant from snout and adipose; 
anal rounded, reaching the caudal. A silvery lateral band, each scale with a pearly base. No black spots or 
other dark markings. 

Another specimen in the Berlin Museum, in which the lateral band is almost faded out, leaves no doubt 
but that margaritaceus is simply a faded specimen of nigrotwniatus. 



302 MEMOIRS OF THE CARNEGIE MUSEUM 

Two specimens, 128-131 mm. Gluck Island. (C. M. Cat. No. 1822; I. U. 
Cat, No. 12113.) 

Twenty-eight specimens, 66-203 mm. to end of middle caudal rays. Crab 
Falls. (C. M. Cat. No. 1823a-e; I. U. Cat. No. 12114.) 

Eleven specimens, 45-191 mm. Bartica. (C. M. Cat. No. 1824a-c; I. U. 
Cat, No. 12115.) 

Head 4-4.75; depth 4.5-5; D. 12-13; A. 10 or 11. Scales 5 or 6-41 or 42-4; 
eye 1.5-1.75 in snout, 3.6-4 in head. 1.2-1.66 in interorbital. 

Elongate, subterete, little compressed, head subcorneal; back little raised, the 
profile with a scarcely perceptible depression over the eyes. Snout blunt, the 
mouth inferior, four teeth on each side of each jaw. 

Dorsal 5.3-6 in the length, its origin equidistant from tip of snout and end of 
base of adipose, or a little farther back; margin of dorsal rounded; adipose fin 
well-developed; caudal forked, the upper lobe longer, 4.3 in the length; anal 
rounded or truncate, the longer rays always reaching beyond the tips of the shorter 
rays, sometimes to the lower caudal fulcra; ventrals reaching a little more than 
half-way to the vent; pectorals half-way to second third of ventrals. 

Young with twelve dusky bars across the back; an intense spot behind the 
middle of the opercle, three similar but successively fainter spots following it; a 
median dark stripe from below the middle of the dorsal to the caudal, widest and 
most intense in front, All the markings (with the exception of the lateral stripe) 
fading with age. Center of adipose orange in life. 

159. Leporinus friderici (Bloch). (Plate NLIII, fig. 4.) 

Salmo friderici Bloch, Ausl. Fische, VIII, 1795. 78, pi. 378 (Surinam). — Bloch and 
Schneider, Syst. Ichth., 1801, 403. 

Leporinus friderici Muller and Troschel, Horse Ichth., 1, 1845, 11 ; in Schomburgk, 
Reisen, III, 1848, 634 (Pomeroon). — Cuvier and Valenciennes, Hist, Nat. 
Poiss., XXII, 1859, 25 (Essequibo; Surinam; San Francisco; La Plata).— 
Kner, "Familie der Characinen," i, 1859, 34 (Rio Branco). — Gunther, Cata- 
logue, V, 1864, 306 (Essequibo; River Cupai); Proc. Zool. Soc. London, 1868, 
244 (Xeberos). — Steindachner, " Susswasserfische d. Stidostlichen Brasilien," 
ii, 1875, 13 (Bahia; S. Goncallo; Rio Para ; Porto do Moz; Parahyba; Rio Branco; 
Manacapuru; Jatuarana; Essequibo). — Cope, Proc. Am. Philos. Soc, XVII, 
1878, 690 (Peruvian Amazon). — Eigenmann and Eigenmann, Proc. U. S. 
Nat, Mus., XIV, 1891, 51.— Perugia, Ann. Mus. Genova, (2). XVIII, 1897, 
25 (Alto Beni).— Boulenger, Boll. Mus. Torino, XIII, 1898, 4 (Rio Vinces); 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 303 

XXV, 1900, -- (Urucum).— Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 406 

iManaos) .— Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 328 (Pebas; Peruvian 

Amazon). — Eigenmann and Ogle, Proc. U. S. Nat, Mus., XXXIII, 1907, 7 

(Paraguay).— Eigenmann, Ann. Carnegie Mus., IV, 1907, 125 (Puerto Max); 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 426. 
? Curimatus frederici Perugia, Ann. Mus. Genova, (2 a), X, 1891, 41 (Candelaria). 

-Lahille, Rev. Mus. la Plata, VI, 1895, 7 (Puerto Viejo; Punta Lara). 
Curimatus acutidens Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 9, 

pi. 8, fig. 1 (La Plata). 
Leporinus leschenauUi Cuvier and Valenciennes, Hist, Nat, Poiss., XXII, 1848. 

30, pi. 635 (Mana).— Gunther, Catalogue, V, 1864, 307 (Andes of western 

Ecuador; River Capin).— Peters, MB. Akad. Wiss. Berlin, 1877, 472 

(Calabozo).— Perugia, Ann. Mus. Genova, (2 a), X, 1891, 41 (Villa Maria, 

Rio Paraguay, Matto Grosso). — Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 

157 (Apure). 
Leporinus megalepis Gunther (in part, i. e., specimens e, f, and m), Catalogue, V, 

1864, 307 (Surinam). 

Twenty-one specimens, 98-259 mm. Tumatumari, above, below, and in 
the falls. (C. M. Cat, No. 1840a-d; I. U. Cat. No. 12130.) 

Four specimens, 75 to about 290 mm. Rockstone. (C. M. Cat, No. 1841; 
I. U. Cat. No. 12131.) 

Nine specimens, 122-272 mm. Crab Falls. (C. M. Cat. No. 1842a-o; 
I. U. Cat, No. 12132.) (figure.) 

Two specimens, 194-195 mm. Kangaruma. (C. M. Cat. No. 1843a; I. 
U. Cat, No. 12133.) 

Six specimens, 147-293 mm. Wismar. (C. M. Cat. No. 1844a; I. U. Cat. 
No. 12134.) 

Six specimens, 146-208 mm. Mud-flats below Wismar. (C, M. Cat, No. 
1845a; I. U. Cat. No. 12135.) 

Forty-four specimens, 77 to about 345 mm. Bartica, rocks. (C. M. Cat. 
No. 1846a-£; I. U. Cat. No. 12136.) 

Head 3.75-4; depth 3.25-3.5; D. 12 or 13; A. 10 or 11. Scales 5-38 to 40-4 
or 5; eye 1.25-1.66 in snout, 3.8-4 in head, 2 in interorbital. 

Compressed, deep, head somewhat wedge-shaped ; profile steep; a scarcely 
perceptible depression over the eyes; mouth subterminal, four teeth on each side 
of each jaw. 

Origin of dorsal nearer adipose than to tip of snout; margin of dorsal rounded, 



304 MEMOIRS OF THE CARNEGIE MUSEUM 

its highest ray about 4.5 in the length; caudal broad, leathery, the upper lobe longer, 
4 in the length; anal obliquely truncate, the longest rays reaching caudal, ventrals 
reaching more than half-way to vent, pectorals half-way to middle of ventrals. 

Bases of all the scales of the side and back dark, the extent of the dark area 
variable; a median dark band along the sides from below the posterior half of 
the dorsal to the caudal in the young, the band becoming broken into two or three 
spots with age; the spot under the dorsal most intense, the one on the base of the 
middle caudal rays small, frequently absent; a spot midway between the two is 
also absent at times. Young with a dark spot below the second and third scale 
of the lateral line, and a series of three fainter ones with cross-shades following it. 

In life the bases of the scales below the lateral line and in front of the lateral 
spot are reddish, the bases of the rest yellowish; pectorals faintly yellow; opercle 
and a streak to the nares golden. 

I have some evidence that I have obtained from Guiana two species of 
Leporinus with spots on the sides. I must, however, leave the final determina- 
tion of this point till the revision of the genus is undertaken. 

Provisionally I may record the following specimen as belonging to the second 
species. 

One specimen, 64 mm. Tumatumari. (C. M. Cat. No. 2214, Plate XLIII, 
fig. 4.) 

Compared with a specimen 75 mm. long referred to friderici from the same place 
we find the following: 

75 mm. 64 mm. 

Depth 3.33. Depth 3. 

Anterior anal ray reaching beyond tip Anterior anal ray reaching tip of last. 

of last. 
D. 13; A. 10. D. 12; A. 10. 

Head 3.66. Head 3.5. 

Scales 5-37-5. Scales 5-37-5. 

A dark spot below the second and third A spot on the second scale of the lateral 

scales of the lateral line; three line; a larger spot on the thirteenth 

fainter vertical spots below the to sixteenth scales, a third on the 

sixth, eighth, and tenth scales of twenty-fifth to twenty-sixth, a 

the lateral line respectively; an fourth on the last three scales; 

oval spot including the thirteenth no lateral band. 

to seventeenth scales of the lateral 

line, a second one including the 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 305 

twenty-fifth to twenty-eighth, a 

third on the thirtieth to thirty- 
second, and a dark spot on the 

base of the caudal; a faint band 

from the thirteenth scale to the 

end of the lateral line. 

The lateral band and unequal caudal lobes arc still quite marked in a specimen 
of friderici 152 mm. and another 250 mm. from Tumatumari, as well as in the 
specimens recorded under that species from Kangaruma, Rockstone, and Crab 
Falls. 

In a specimen 215 mm. long from Tumatumari the caudal lobes are equal, and 
there is but one spot from the thirteenth to the fifteenth scale of the lateral line. 
In the specimens from about Wismar the lateral band is not seen, even in small 
specimens, but the caudal lobes are unequal. 

160. Leporinus maculatus Muller and Troschel. (Plate XLIII, fig. 2.) 

"Wacucu" of the Indians about the Kaieteur. 

Leporinus maculatus Muller and Troschel, Horse Ichth., I, 1845, 11 (Guiana); 

in Schomburgk, Reisen, III, 1848, 634 (Rupununi; Awaricuru). — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 427. 
Leporinus megalepis Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 

(Essequibo); Catalogue, V, 1864, 307, part (Essequibo; River Cupai; Bahia; 

Rio Janeiro); Proc. Zool. Soc. London, 1868, 244 (Xeberos). — Cope, Proc. 

Acad. Nat. Sci. Phila., 1871, 259 (Ambyiacu). — Steindachner, "Fisch-fauna 

d. Magdalenen-Stromes," 1878, 38, note. — Eigenmann and Eigenmann, Proc. 

IT. S. Nat. Mus., XIV, 1891, 51.— Vaillant, Bull. Mus. d'Hist. Nat., V, 1899, 

155 (Carnot).— Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907. 

7 (Rio das Velhas). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 426. 
Leporinus marccjravii Lutken, Overs. Dan. Vidensk. Selsk. Forh., 1874, 130 (Rio 

das Velhas and tributaries); Dan. Vidensk. Selsk. Skr., (5), XII, 1875, 202. 

pi. 4, fig. 9; and p. xii (Rio das Velhas). 

Ten specimens, 99-146 mm. Tukeit. (C. M. Cat. No. 1833a-c; I. U. Cat. 
No. 12123.) 

Twelve specimens, 58-73 mm. Amatuk. (C. M. Cat, No. 1834a-c; I. U. 
Cat. No. 12124.) 

Seven specimens, 90-129 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1835a-6; I. U. Cat. No. 12125.) 



306 MEMOIRS OF THE CARNEGIE MUSEUM 

Three specimens, 90-125 mm. Tumatumari. (C. M. Cat. No. 1836a; I. IT. 
Cat. No. 12126.) 

Three specimens, 73-110 mm. Crab Falls. (C. M. Cat. No. 1837a; I. U. 
Cat. No. 12127.) 

Four specimens, 89-106 mm. Bartica. (C. M. Cat. No. 1838a-6; I. U. Cat. 
No. 12128.) 

I have examined the types of maculatus in the Berlin Museum. They are in 
a bad state of preservation, but undoubtedly belong to this species or the next- 
Inasmuch as they are from the Essequibo basin, they more probably belong to this 
species. 

Head 4.5-4.6; depth 3-3.6; D. 12; A. 10; scales 5-32 or 34-3.5; eyes 1.3 in 
snout, 3.5 in head, 1.5 in interorbital. 

Elongate, the width half as great as the depth; a distinct depression in the 
profile over the eye; snout bluntly conical, projecting beyond the small mouth, 
which is strictly inferior; three teeth on each side of each jaw. 

Origin of dorsal about equidistant from snout and end of adipose; highest 
dorsal ray a little more than 4 in the length ; upper caudal lobe considerably longer 
than the lower, about 3 in the length; anal emarginate, the highest ray scarcely, if 
at all, reaching beyond the tip of the last, sometimes not reaching it ; anal not reaching 
caudal; ventrals reaching about half-way to middle of anal, pectorals half-way to 
last third or fourth of the ventrals. 

A large oval black spot on the middle of the sides below the posterior part of 
the dorsal, a smaller less intense spot half-way between it and the caudal, and a 
still smaller one at the base of the caudal; a dark streak upward and forward from 
the eye, meeting its fellow on the snout; a dark band connecting the eyes; about 
nine short dark bands across the back; a dark spot on the lower part of the opercle, 
a smaller one between it and the orbit, in contact with the latter, another on the 
upper part of the gill-opening; a row of three spots on the sides, in a line continuous 
with the third dorsal bar in front of the dorsal; a similar row of larger spots con- 
tinuous with the second bar in front of the dorsal; a spot below the middle of the 
large median spot, another below the space between the two lateral spots; some- 
times the lower ends of some of the dorsal bands are separated as spots above the 
line of the median lateral spots; a spot at base of origin of anal; another above the 
end of the anal ; caudal peduncle with a median dark spot and other dark shades or 
spots; posterior part of anal dark. The position and shape of the spots varies in 
the different individuals. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 307 

161. Leporinus granti sp. nov. (Plate XLIII, fig. 3.) 

Type, 144 mm. Maripicru Creek. (Carnegie Museum Catalog of Fishes 
No. 1851.) 

Cotypes, eight specimens, 108-185 mm. Maripicru Creek. (C. M. Cat. No. 
1839a; I. U. Cat. No. 12129.) 

These specimens differ from L. megalepis in the shape of the mouth and in the 
shape of the spots. 

Mouth terminal; lateral spots more elongate, the row from near the upper 
angle of the gill-opening tending to form a continuous band with the lowermost 
spots of the sides; four teeth on the side of each jaw; lips much thicker than in L. 
megalepis; otherwise as in that species. 

This species is named for Mr. William Grant, my most efficient Indian guide 
on the Potaro, who later made additional collections, which among other new 
species contained this. 

162. Leporinus alternus sp. nov. 
"Porchina" of the Wacusi Indians. 

Type, 200 mm. Tukeit. (Carnegie Museum Catalog of Fishes No. 1827.) 
Cotype, one specimen, 158 mm. Tumatumari. (C. M. Cat. No. 1826.) 
Cotype, one specimen, 132 mm. Tukeit, (I. U. Cat. No. 12117.) 
Cotypes, twelve specimens, 52-137 mm. Bartica. (C. M. Cat. No. 1828a-c; 

I. U. Cat. No. 12118.) 

Head 4-4.2; depth 4; D. 12; A. 10 or 11; scales 5-38 or 39-4 or 5; eye 1.5- 

1.75 in snout, 3.5-3.75 in head, 1.75 in interorbital. 

Elongate, subterete, the width 1.5 in the depth; preventral area rounded; 

head subconical, the mouth subterrninal ; four graduated, obliquely-pointed teeth 

in each jaw. 

Dorsal rounded, its highest ray about 5 in the length, its origin nearer to tip of 

adipose than to snout; caudal deeply forked, the upper lobe 3.5 in the length; anal 

obliquely truncate, the lobe reaching caudal in the type, sometimes shorter; ventrals 

reaching half-way to anal or shorter, pectorals not half-way to middle of ventrals. 
Seven cross-bands, the ones over pectorals, below dorsal, in front of anal, and 

at base of caudal, broad and heavy, the others much narrower. 

163. Leporinus fasciatus (Bloch). 
Salmo fasciatus Bloch, Ausl. Fische, 1795, pi. 379. 

Leporinus fasciatus Ctjvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 34 
(Surinam). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 634 



308 MEMOIRS OF THE CARNEGIE MUSEUM 

(Pirara). — Kner, "Familie der Characinen," i, 1859, 35 (Irisanga). — Gunther, 

Catalogue, V, 1864, 308 (Essequibo; River Cupai). — Peters, MB. Akad. Wiss. 

Berlin, 1877, 472 (Calabozo). — Steindachner, "Flussfische Sudamerika's," i. 

1879, 7 (Orinoco near Ciudad Bolivar). — Eigenmann and Eigenmann, Proc. 

U. S. Nat. Mus., XIV, 1891, 51.— Fowler, Proc. Acad. Nat, Sci. Phila., 1906, 

328 (Rio Parahyba). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 427. 
Leporinus novemfasciatus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 65, 

pi 37. 

Eighteen specimens, 74 to about 335 mm. Crab Falls. (C. M. Cat. No 
1847a-e; I. U. Cat. No. 12137.) 

Three specimens, 74-140 mm. Rockstone Stelling. (C. M. Cat. No. 1848; 
I. U. Cat. No. 12138.) 

One specimen, 219 mm. Tumatumari, in the cataract. (C. M. Cat. No. 
1849.) 

Forty specimens, 68-315 mm. Bartica. (C. M. Cat. No. 1850a-?'; I. U. Cat. 
No. 12139.) 

One specimen, 52 mm. Konawaruk. (C. M. Cat. No. 2209.) 

Head 4.25; depth 3.75; D. 12; A. 10; scales 6 or 7-41-6; eye 2 in snout, 4.5 
in head, 2.5 in interorbital in the largest specimen; 1.25 in snout, 3 in head, 1.25 
in interorbital in the smallest. 

Elongate, the width a little more than half the height. Profile gently arched, 
with a scarcely perceptible change in the curve over the eye. Preventral area 
broad, rounded; snout conical, the mouth terminal; four teeth in each side of each 
jaw. 

Dorsal obliquely rounded, the highest ray 4.5-5 in the length; caudal broad, 
the upper lobe 3.3-3.5 in the length. Anal very obliquely truncate or falcate, the 
anterior lobe extending beyond the origin of the caudal; ventrals reaching half- 
way to middle of anal in adult; pectorals half-way to middle of ventrals or beyond. 

Young with the snout, a band through and over the eye, and another across 
the opercle and nape, black; five black bands encircling the body, one in front of 
the dorsal, one below and behind the dorsal, one in front and one behind the anal, 
and one at the end of the caudal peduncle. The first two split into two bands 
when a length of 75 mm. is reached, the next two begin to split at a length of 200 
mm., the components moving apart; in the adult there are ten obscure bars about 
equally spaced, beginning with the one across the opercle. Upper fins and posterior 
part of anal dark blue. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 309 

In life the lower surface of the head is mottled with orange, and the lower sides 
and belly tinged with the same. Pectoral rays pink, yellow at the base; ventral 
rays maroon, yellow at base; anal rays bright orange, the membrane olive at base; 
caudal and adipose blackish blue, dorsal and upper sides similar, but a little lighter. 

Subfamily Crenuchhnme. 
Crenuchus G tint her. 
Crenuchus Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 448. 
Type, Crenuchus spilurus Gunther. 

Distinguished from all other American characins by its numerous, tricuspid 
teeth, in a single series in each jaw, by the long dorsal fin, and by the presence 
of an adipose fin. A broad depression between the eyes, but no frontal fontanel; 
parietal fontanel large, ovate; gill-membrane free; lateral line incomplete. 

164. Crenuchus spilurus Gunther. 
Crenuchus spilurus Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 448 

(Essequibo); Catalogue, V, 1864, 365. — Steindachner, "Ichthyologische 

Beitrage." v, 1876. 83 (Tabatinga, Hyavary). — Eigenmann and Eigenmann, 

Proc. U. S. Nat. Mus., XIV, 1891, 59. — Eigenmann, Repts. Princeton Univ. 

Exp. Patagonia, III, 1910, 430. 

Five specimens, 43-56 mm. Georgetown trenches. (C. M. Cat. No. 1867a; 
I. U. Cat. No. 12152.) 

Three specimens, 40-45 mm. Kumaka, (C. M. Cat. No. 1868a; I. U. Cat. 
No. 12153.) 

Two specimens, 27-30 mm. Christianburg Canal. (C. M. Cat. No. 1869a; 
I. U. Cat. No. 12154.) 

One specimen, 43 mm. Mud-flats below Wismar. (C. M. Cat. No. 1870a.) 

Two specimens, 35-43 mm. Essequibo, below Packeoo Falls. (C. M. Cat. 
No. 1871a; I. U.Cat. No. 12155.) 

Two specimens, 35-39 mm. Macluni Creek. (C. M. Cat. No. 1872a; I. U. 
Cat, No. 12156.) 

Two specimens, 40-43 mm. Aruka River. (C. M. Cat. No. 1883a; I. U. 
Cat, No. 12157.) 

Two specimens, about 35 mm. Rockstone. (C. M. Cat. No. 2211.) 

Head 3-3.25; depth 3.2-3.5; D. 18; A. 11; scales 6-29 to 32-3, five to seven 
with pores; eye .75 in snout, 3.5 in head, a little more than interorbital. 

Compressed, with the dorsal and ventral outlines about equally arched; mouth 



310 MEMOIRS OF THE CARNEGIE MUSEUM 

large; maxillary-premaxillary line forming a continuous curve, equal to half the 
length of the head (without subopercle) ; each side of each jaw with about twelve to 
fifteen tricuspid teeth in a single series. No teeth on the maxillary; suborbitals 
leaving about half the cheek naked. 

Origin of dorsal equidistant from snout and tip of adipose or upper caudal 
lobe, the rays nearly equal in height in the female, the eighth to the twelfth of the 
male prolonged, reaching the caudal; anal rounded in the female, lanceolate in the 
male, the middle rays reaching beyond basal fifth of the caudal; ventrals reaching 
more than half-way to end of anal; pectorals half-way to middle of ventrals. 

Sides uniformly dotted ; a large spot a little below the middle at the end of the 
caudal peduncle; last rays and sometimes base of the dorsal and last rays of the 
anal hyaline, the rest of these fins uniformly dark with irregular bars or spots; corre- 
sponding parts of dorsal and anal in male with conspicuous semi-hyaline oval 
spots surrounded by much darker. 

Pcecilocharax Eigenmann. 
Pcecilocharax Eigenmann, Ann. Carnegie Mus., VI, 1909, 34. 
Type, the single species. 

165. Pcecilocharax bovallii Eigenmann. (Plate XLIV, figs. 1, 2.) 

"Guabia"; "Wabeak." 
Pcecilocharax bovallii Eigenmann, Ann. Carnegie Museum, VI, 1909, 34. 

Types, male, 43 mm.; female, 40 mm. Creek at Savannah Landing. (Car- 
negie Museum Catalog of Fishes No. 1136a-&.) 

Cotypes, over two hundred and twenty specimens. Creek at Savannah Land- 
ing. (C. M. Cat. No. 1137a-z; I. U. Cat. No. 11686.) 

Cotypes, three specimens, 34-45 mm. Holmia. (C. M. Cat. No. 1138a; I. U. 
Cat. No. 11671.) 

Cotype, one specimen, 38 mm. Two hours below Holmia. (C. M. Cat. No. 
11390.) 

Cotypes, sixty-three specimens, 22-47 mm. Creek at Tukeit. (C. M. Cat 
No. 1040a-z; I. U. Cat. No. 11672.) 

Head 3-3.5; depth 3.2-3.3; D 16; A. 11; scales 27-30, nine between dorsal and 
ventral, six with pores; eye equal to the snout, 3.5-4 in the head; interorbital almost 
equal to the eye. 

Compressed, ventral profile gently and evenly arched. Dorsal outline rather 
steep to near the dorsal fin. Preventral and predorsal areas narrowly rounded, 
scaled. 



eigenmann: the freshwater fishes of British guiana 311 

Occipital process short, the fontanel large, oval, separated from the small 
frontal fontanel by a convex bridge on a level with the rest of the skull; suborbitals 
narrow, leaving most of the cheek naked. Mouth small, maxillary-premaxillary 
border 2.8 in the head; maxillary not quite equal to the eye. Teeth all long, 
tricuspid, in a single series, about eleven in the premaxillary, about five in the 
maxillary. 

Gill-rakers 7 + 9, about equal to the pupil. 

Origin of dorsal nearer to snout than to caudal, its rays of nearly uniform 
height, none prolonged. Anal considerably shorter than the dorsal, its middle 
rays highest, reaching in the male to middle of caudal; origin of anal under one 
of the last four dorsal rays; origin of ventrals and dorsal equidistant from snout; 
tips of ventrals reaching to the anal in the male, the ventrals slightly shorter in the 
female. Pectorals not quite reaching ventrals. 

Scales cycloid, regularly imbricate, no interpolated scales. No scales on the 
anal, those along the base forming a sheath. Caudal naked. A very minute 
axillary scale. 

Back dusky, margined by a darker stripe from above eye to upper caudal lobe. 
A light band from upper part of eye, becoming widest under the middle to end of 
dorsal in the male, widest on caudal peduncle, contracted on caudal fin in the 
female. A dark band from eye to upper part of gill-opening, thence descending to 
meet its fellow on the lower surface and edge of caudal peduncle, thence curved 
up on the caudal to tips of its middle rays; this band more intense, jagged, and 
more strongly decurved in the male than in the female. Sides of caudal peduncle 
with a rusty spot on each scale (female) ; dorsal in both sexes nearly uniform, 
darkest in the male. Upper margin of caudal geranium-red, most intense in the 
male, below which is a continuation of the upper dark band of the sides, fading out 
toward tip of upper lobe and with oval hyaline spots; a wedge-shaped area at 
middle of caudal and all but the base of some of the rays of the lower lobe hyaline. 
Tij) 0I ana l i n male scarlet, below which is a broad dark band, base and last rays 
hyaline. Last rays of anal (female) hyaline, otherwise dark with conspicuous 
round or oval hyaline spots. Ventrals slightly dusky. Pectorals hyaline. 

Subfamily APHYOCHARACiNiE. 
Odontostilbe Cope. 
Odontostilbe Cope, Proc. Am. Philos. Soc, XI, 1870, 566. 
Type, Odontostilbe fugitiva Cope. 

Minute fishes, with multicuspid incisors in a single series in each jaw, and a 
complete lateral line. 



312 MEMOIRS OF THE CARNEGIE MUSEUM 

166. Odontostilbe melandetus sp. nov. (Plate XLIV, fig. 3.) 

Type, 27 mm. Locality? (Carnegie Museum Catalog of Fishes No. 1878.) 

Cotypes, three specimens, about 27-35 mm. Locality? (I. U. Cat. No. 
12160.) 

Readily distinguished by the black margin of the caudal peduncle. 

Head 3.75; depth 3.6; D. 10; A. 21; scales 4-34 or 35-3. Eye 2.5-2.7 in the 
head; interorbital but little narrower than the eye. 

Minute, compressed, head bluntish, the mouth terminal; a median series of 
ten scales in front of the dorsal. Maxillary very slender, reaching to below the eye; 
maxillary-premaxillary border as long as the eye; ten to fourteen teeth on the pre- 
maxillary, four to seven on the maxillary. 

Scales very regularly imbricate, with concentric, but without longitudinal, 
stria?; lateral line complete, scarcely decurved; anal naked; base of caudal with 
a few scales. 

Fins all well-developed, the anal deeply emarginate; pectorals not quite reach- 
ing ventrals, ventrals not to anal. 

No chromatophores on the sides; scales of the back with marginal series of 
chromatophores; a series of black specks along the base of the anal, the caudal 
peduncle margined with black. 

Aphyocharax 35 Gunther. 
Aphyocharax Gunther, Proc. Zool. Soc. London, 1868, 254. 

Type, Aphyocharax pusillus Gunther. 

Minute, slender fishes, with a single series of tricuspid teeth in the premaxillary, 
and a few teeth in the maxillary. Lateral line incomplete; gill-membranes free 
from the isthmus; a frontal and a parietal fontanel. 

Key to the Guiana Species of Aphyocharax. 
a. Dorsal with a black spot, humeral spot very faint, no caudal spot. A. 25; scales 5-7+25-2.. . melanotus. 
aa. Dorsal without a black spot; anal plain; about fourteen scales in front of the dorsal; lateral line 34-37; 
A. 17 erythrurus. 

167. Aphyocharax melanotus sp. nov. 

Type unique, about 43 mm. Rockstone sand-bank. (Carnegie Museum 
Catalog of Fishes No. 1877.) 

This is the only Guiana species of the genus with a black dorsal spot. 

Head 4; depth 3.8; D. 10; A. 25; scales 5-6 + 27-2; eye much longer than 
snout, 2.75 in head; interorbital 3.75 in the head. 

35 afyi-n, a small fish; charax, a genus of characins. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 313 

Compressed, preventral and predorsal areas rounded, the latter with a median 
series of ten scales. 

Mouth large, the antero-posterior extent of the premaxillary very short, the 
maxillary with a curved anterior margin, its length about equal to that of the eye; 
about twelve teeth in each premaxillary ; maxillary with about four similar teeth; 
about twenty teeth on each side of the lower jaw. 

Scales c} r cloid. regularly imbricate, six scales with pores; caudal naked. 

Ventrals just reaching anal; pectorals not reaching the ventrals. 

Very few color-cells on the sides; scales of the back margined with dusky; 
upper part of the first few dorsal rays black. 

Three small specimens (C. M. Cat. No. 1891; I. U. Cat, No. 12163) probably 
belong to this species. 

168. Aphyocharax erythrurus sp. nov. (Plate XLIV, fig. 4.) 

Type, 57 mm. Rockstone sand-bank. (Carnegie Museum Catalog of 
Fishes No. 1879.) 

Cotypes, thirty-seven specimens, 28-58 mm. Rockstone sand-bank. (C. M. 
Cat. No. 1880a-e; I. U. Cat, No. 12161.) 

Cotype, one specimen, 29 mm. to base of caudal. Maripicru Creek. (C. M. 
Cat. No. 1881a.) 

Cotype, one specimen, 35 mm. Crab Falls. (C. M. Cat. No. 2494.) 

Head about 4; depth 3.66-4; D. 10 or 11; A. 17; scales 5-34 to 37-3 36 ; nine 
to eleven scales with pores; eye in adult a- little longer than snout, 3.5 in the 
head; interorbital 3 in the head. 

Elongate, preventral area with a median series of about thirteen scales; pre- 
dorsal area with a median series of fourteen scales, the series irregular anteriorly; 
head somewhat blunt, the mouth terminal, oblique; maxillary-premaxillary border 
forming a continuous curve, its length 2.5 in the length of the head; six teeth in 
each premaxillary; about thirteen in each dentary, and about twelve to fourteen 
along the greater part of the maxillary. 

Scales regularly imbricate, each scale of half-grown specimens with a median 
fifth free from stria?, above and below this with numerous parallel horizontal lines; 
anal and caudal naked. 

Dorsal behind the ventrals; caudal deeply forked; anal emarginate; ventrals 
not reaching anal; pectorals not emarginate; pectorals not to ventrals. 

Straw-colored; a diffuse humeral spot; caudal brick-red in life. 

36 And a few small ones on the caudal. 



314 MEMOIRS OF THE CARNEGIE MUSEUM 

Aphyodite 37 gen. no v. 
Type, the only species, A. grammica. 
This is an Aphyocharax with a scaled caudal. 

169. Aphyodite grammica sp. nov. (Plate XLIV, fig. 5.) 

Type, about 32 mm. Konawaruk. (Carnegie Museum Catalog of Fishes 
No. 1882.) 

Cotypes, two specimens, 30-32 mm. Konawaruk. (I. U. Cat. No. 12162.) 

Head 4.5; depth 3.33; D. 11; A. 22; scales 4-7 + 23-3. Eye twice as long- 
as the snout, 2.5 in the head; interorbital a little less than the eye. 

Compressed, slender. Head short, compressed, the snout small, oblique; the 
maxillary not reaching to below the eye; cheeks small, entirely covered by the 
suborbital; maxillary margin convex, with three scarcely perceptible teeth; each 
premaxillary with about ten teeth. 

Scales regularly imbricate, caudal lobes scaled to near their tips. 

Adipose fin well-developed; anal emarginate; ventrals not reaching anal, 
pectorals not to ventrals. 

Scales of the back margined with dark; a black median line; black at base of 
ventrals and base of anal. 

Subfamily Iguanodectin^e. 
Iguanodectes Cope. 
Iguanodectes Cope, Proc. Acad. Nat. Sci. Phila., 1871, 260, pi. 8, fig. 1. 
Type, Iguanodectes tenuis Cope. 
Range : Guianas and Amazons. 

Gill-membranes united, free from the isthmus; upper jaw with two series of 
pluricuspid incisors, the outer series consisting of a single tooth in each side. Slen- 
der; anal long; lateral line complete. 
One species known. 

170. Iguanodectes tenuis Cope. 

Iguanodectes tenuis Cope, Proc. Acad. Nat. Sci. Phila., 1871, 260, pi. 8, fig. 1 
(Ambyiacu). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XVI, 1891, 
54. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 430. 
One specimen, 54 mm. Wismar. (C. M. Cat. No. 1884.) 
Fifteen specimens, 35-92 mm. Rockstone sand-bank. (C. M. Cat. No. 

1885a-d; I. U. Cat. No. 12164.) 

37 a<t>iiy, a small fish; She, born of. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 315 

Four specimens, 68-75 mm. Gluck Island. (C. M. Cat. No. 1886a; I. U. 
Cat. No. 12165.) 

Ten specimens, 57-73 mm. Konawaruk. (C. M. Cat. No. 1887a-6; I. U. 
Cat. No. 12166.) 

Six specimens, 53-74 mm. Warraputa. (C. M. Cat, No. 1888a-6; I. U. Cat. 
No. 12167.) 

One specimen, 79 mm. Tumatumari. (C. M. Cat. No. 1889.) 

Seventeen specimens, 65-85 mm. Rupununi. (C. M. Cat, No. 1890a-d; 
I. U. Cat. No. 12168.) 

Head 4.3-5; depth 4.5; D. 10; A. 35 or 36; scales 8-65 or 66-5. Eye 1 in 
snout, 3 in head, 1 in interorbital in the largest; .75, 2.5, and 1 respectively in the 
smallest, 

Slender, compressed, resembling Creatochanes; ventral arch slightly greater 
than the dorsal; preventral area rounded, predorsal area similar, neither with a 
distinct median series of scales. 

Occipital crest short, about 9 in the distance from its base to the dorsal; 
fontanels broad, ihe parietal fontanel twice as long as the frontal, which extends 
to above the middle of the eye; interorbital convex; jaws equal, the mouth ter- 
minal, short, the maxillary meeting the premaxillary at an angle; cheeks narrow, 
entirely covered by the suborbitals. Premaxillary with five pluricuspid teeth in 
the inner series, a single much narrower tooth in front of the space between the 
first and second tooth; maxillary with one or two teeth similar to those of the 
inner teeth of the premaxillary; seven similar graduate teeth on each side of the 
lower jaw. 

Gill-rakers short, slender, 5 + 10. 

Scales thin, adherent, regularly imbricate, with few radiating striae. Anal and 
caudal naked; lateral line slightly decurved; axillary scale well-developed. 

Origin of dorsal equidistant from base of middle caudal rays and middle or 
anterior margin of eye, its height less than one-fifth of the length; adipose fin 
small; caudal forked, its lobes about 5 in the length; anal very long, emarginate in 
front, its base about 3 in the length; ventrals scarcely reaching anal. Pectorals 
broad, placed low, their bases nearly horizontal, their tips not quite reaching the 
ventrals. 

Iridescent, a rusty spot on upper part of caudal peduncle; upper caudal lobe 
dark, darkest towards the base of the middle rays; a silvery lateral band; a black 
dorsal line. 



316 MEMOIRS OF THE CARNEGIE MUSEUM 

Piabucus Cuvier. 
"Les Piabuques" Cuvier, Regne Animal, II, 1817, 166 (argentinus). 
Piabucus Oken, Isis, 1817, 1183. 

Type, Salmo argentinus Linnaeus. 

With the character of Iguanodectes, but with the preventral area sharply 
trenchant. 

Three species, of which one was taken in Guiana. 

171. Piabucus dentatus Koelreuter. 

"Piabuca" Marcgrave, Hist. Rer. Nat. Bras., IV, 1648, 170. 

Trutta dentata Koelreuter, Nov. Comm. Petropoli, VIII, 1761, 413, pi. 14, fig. 4. 

Piabucus dentatus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
440. 

Salmo argentinus Linnaeus, Syst. Nat., ed. 12, 1766, 511. — Bloch, Ausl. Fische, 
1785, pi. 382, fig. 1. —Bloch and Schneider, Syst. Ichth., 1801, 403. 

Characinus argentinus Lacepede, Hist. Nat. Poiss., V, 1790, 272. 

Piabuca argentina Cuvier, Regne Animal, II, 1817, 310 (fide Miiller and Troschel).— 
Muller and Troschel, Hor. Ichth., I, 1845, 9, pi. 1, fig. 1; in Schomburgk, 
Reisen, III, 1848, 633 (Lake Amucu and Savannah swamps). — Cuvier and 
Valenciennes, Hist. Nat. Poiss., XVII, 1848, 108. — Gunther, Catalogue, V, 
1864, 344. — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 
57. — Steindachner, " Ichthyologische Beitrage," xv, 1891, 22 (Iquitos). 
Eight specimens, 102-138 mm. Koreabo Rubber Plantation. (C. M. Cat. 

No. 1891a-6; I. U. Cat. No. 12169.) 

Two specimens, 149-155 mm. Wismar. (C. M. Cat. No. 1892; I. U. Cat. 

No. 12170.) 

Head 5.66-6.3; depth 3.6-3.66; D. 10 or 11; A. 43-45; scales 11-84-7. Eye 

1 in snout, 3.25 in head, 1.5 in interorbital. 

Elongate, compressed; profile depressed over the nape and eyes; ventral profile 

exaggerated in front of the ventrals; predorsal area narrowly rounded, preventral 

area compressed to an edge, the region between the bases of the pectorals stiff, the 

region just in front of the ventrals with a flexible ridge of scales. 

Occipital crest narrow, reaching about one-seventh of the distance from its base 

to the dorsal; parietal fontanel broad, more than twice as long as the frontal, which 

is nearly equilaterally triangular; mouth small, terminal, the jaws subequal, pre- 

maxillary meeting the minute maxillary at an angle. Six or seven pluricuspid 

teeth in the inner row of the premaxillary, the outer row composed of a single 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 317 

tooth on each side of each jaw, similar to, but narrower than, those of the inner 
series; two similar teeth on the maxillary and seven similar ones on each side of the 
lower jaw; cheeks narrow, entirely covered by the suborbitals. 

Scales thin, cycloid, deeply imbricate, with few (or more frequently no) radial 
stria?; caudal and anal naked; lateral line complete, decurrent; dorsal short, its 
length less than half its height, which is 6.75 in the length; lower caudal lobe the 
longer, 4.5 in the length; origin of anal under origin of dorsal or a little farther 
forward; ventrals small, not reaching anal, in contact along their inner margin 
when closed; pectorals large, directed downward and backward when closed, the 
tips projecting beyond the ventral profile, not reaching the ventrals; when opened 
the margins of the pectorals are in one plane. 

Iridescent, the middle caudal rays dusky, otherwise without marking. 

Subfamily Agoniatin^e. 
Agoniates Muller and Troschel. 

Agoniates Muller and Troschel, Hor. Ichth., I, 1845, 33 (halecinus). 

Type, Agoniates halecinus Muller and Troschel. 

Breast trenchant, not expanded; maxillary and mandible with a single series, 
premaxillary with two series of teeth, those of the inner series of the premaxillary 
tricuspid; a large canine on the mandible on each side anteriorly, received in a 
groove on the palate; a few minute tricuspid teeth between the anterior canine 
teeth, a pair of conical teeth within the outer series in front; seven or eight conical 
teeth on the side of the lower jaw behind the fangs, the third largest; cheeks 
entirely covered. 

A genus of one species. 

172. Agoniates halecinus Muller and Troschel. 

Agoniates halecinus Muller and Troschel, Hora? Ichth., I, 1845, 33, pi. 7, fig. 2 
(Guiana); in Schomburgk, Reisen, III, 1848, 636 (Cuyuni). — Cuvier and 
Valenciennes, Hist. Nat. Poiss., 1848, 347. — Gunther, Catalogue, V, 1864, 
344. — Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 57 — 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 440. 
Head 4.66 in the length; depth somewhat less than the length of the head; 

A. 30; lateral line 39, silvery. 

This species, which greatly resembles Hydrolycus scomberoides, is known from 

the type only, about 100 mm. long, in the Berlin Museum. 



318 MEMOIRS OF THE CARNEGIE MUSEUM 

Subfamily Tetragonopterin^e. 

As a full account of the Tetragonopterinae is about to be published in the 
Memoirs of the Museum of Comparative Zoology, the account of these species given 
in this work is, therefore, made brief. 

Tetragonopterus Cuvier. 

" Tetragonoptrus " Artedi, in Seba, Locupl. Rer. Nat. Thes. Ace. Descr., Ill, 

1748, pi. 34, fig. 3. 
Tetragonopterus Cuvier, Regne Animal, II, 1817, 166 (argenteus). 

Type, Tetragonopterus argenteus Cuvier. 




Fig. 37. Tetragonopterus argenteus Cuvier. No. 20718 Mus. Comp. Zool. 

The depth at least half the length ; humped at the occiput ; concave over the 
eyes; premaxillary teeth in two rows, those of the outer series small, of nearly 
uniform size, the row more or less regular, those of the inner series larger, graduated, 
multicuspid, the cusps of each tooth arranged in a curve, the middle cusp much the 
longest; several large, graduated, pointed teeth in the front of the lower jaw, and 
abruptly minute teeth on the sides; maxillary with or without teeth on its upper 
anterior edge; preventral area flat, bounded by sharp angles; a median series of 
scales on the breast. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 319 

Key to the Guiana Species of Tetragonopterus. 

<i. A. 36; scales in front of dorsal crowded, about fifteen in the median line; occipital process bordered by 
seven scales on each side; caudal scaled on its basal part only; scales 8-33-4; head 3.33; depth 1.70; 
eye 2.3 in head, .8 in interorbital; pectoral extending three scales beyond origin of ventrals: a black 

bar across base of caudal; two oblique bars across anterior part of sides argenteus. 

aa. A. 31-33; scales in front of dorsal normal, eight or nine in the median line; occipital process bordered by 
four scales; caudal more densely scaled; scales 7 or 8-33-3.5; head 3.66; depth 1.7-2; eye 2.33; inter- 
orbital 2.5 in the head; pectoral extending to the ventrals or one scale beyond them; a black spot or 
bar at the base of the caudal; two faint oblique bars across anterior part of the sides chalceus. 




Fig. 38. Tetragonopterus chalceus Agassiz. No. 20718 Mus. Comp. Zool. 

173. Tetragonopterus argenteus Cuvier. 

Tetragonopterus argenteus Cuvier, Mem. Mus. d'Hist. Nat., IV, 1818, 455. — Muller 
and Troschel, in Schomburgk, Reisen, III, 1848, 634 (Amucu). — Kner, 
"Familie der Characinen," i, 1859, 38 (Cajaba; Guiana).— Steindachner, 
"Flussfische Slidamerika's," i, 1879, 7 (Orinoco near Ciudad Bolivar).— 
Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 438. 

Tetragonopterus rufipes Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 
pi. 2, fig. 2. 

Tetragonopterus saxva Castelnau, Anim. Am. Sud, Poiss., 1855, 65, pi. 33, fig. 
1 (Rio Coxas). 

Tetragonopterus chalceus (not of Agassiz) Eigenmann and Kennedy, Proc. Acad. 
Nat. Sci. Phila., 1903, 523. 



320 MEMOIRS OF THE CARNEGIE MUSEUM 

For the full bibliography of this species, found from the Orinoco to Buenos 
Aires and from Para to Iquitos, see the paper by the writer in the Memoirs of the 
Museum of Comparative Zoology. 

One specimen, 67 mm. Tumatumari. (C. M. Cat. No. 1489.) 

174. Tetragonopterus chalceus Agassiz. 
" Coregonus amboinensis" Artedi, Ichthyologia, 1738, Species 44. 
Tetragonopterus chalceus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 70, pi. 

33, fig. 1.— Cuvier and Valenciennes. Hist. Nat, Poiss., XXII, 1848, 140 

(no specimens). — Kner, "Familie der Characinen," i, 1859, 38 (Rio Negro; 

Surinam). — Gunther, Catalogue, V, 1864, 320 (British Guiana; Essequibo). — 

Vaillant, Bull. Mus. d'Hist. Nat., V, 1899, 154 (Carsevenne) . — Pellegrin, 

Bull. Mus. d'Hist. Nat., V, 1899, 157 (Apure).— Eigenmann, Repts. Princeton 

Univ. Exp. Patagonia, III, 1910, 438. 
? Tetragonopterus artedii Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 

1848, 128 (Surinam). 
Tetragonopterus schomburgkii Cuvier and Valenciennes, Hist. Nat. Poiss., 

XXII, 1848, 137 (Essequibo). 
Tetragonopterus ortoni Gill, Proc. Acad. Nat. Sci. Phila., 1870, 92. 

Four specimens, 58-68 mm. Wismar. (C M. Cat. No. 1377a; I. U. Cat, 
No. 11852.) 

Six- specimens, 68-71 mm. Bartica. (C. M. Cat. No. 1378a-6; I. U. Cat. 
No. 11853.) 

Fifteen specimens, 47-76 mm. Tumatumari. (C. M. Cat. No. 1379a-e; I. 
U. Cat. No. 11854.) 

Eighteen specimens, 50-91 mm. Crab Falls. (C. M. Cat. No. 1380a-/; 
I. U. Cat, No. 11855.) 

Forty-eight specimens, 41-49 mm. Rockstone. (C. M. Cat. No. 1381a-,;'; 
I. U. Cat. No. 11856.) 

( !haracters as given in the key and figure. For a full account see the Memoirs 
of the Museum of Comparative Zoology. 

Mcenkhausia Eigenmann. 
Moenkhausia Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1903, 145. 

Type, Tetragonopterus xiuguensis Steindachner. 

Two series of notched teeth in the premaxillary; maxillary with a few teeth; 
caudal scaled, its lobes equal, anal naked; lateral line complete, 38 little decurved; 
scales entire. 

39 Except sometimes in M. cotinho. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 321 

Only outlines of the characters of the species of this genus are given. A full 
account of all of them will appear in the Memoirs of the Museum of Comparative 
Zoology, 1911. 

Key to the Guiana Species (if Mcenkhausia. 
a. Depth 2-2.7; A. 23-30; occipital process one-third to one-fifth of the distance of its base from the dorsal. 
b. A broad black band across the base of the caudal, bordered by yellow in front ; A. 25 or 26; scales 5-30 

or 31—4 oligolepis. 

bb. Caudal plain or with a small basal spot. 

c. Depth less than 2 in the length; A. 34; scales 7.5-35-7 profunda. 

cc. Depth 2 or more in the length. 

d. Eye 2.3 or more in the head ; no caudal spots. 

e. Striae of scales diverging from the middle line of each scale in nearly opposite directions; 

depth 2 in the adult; A. 26-28; scales 5-33-4 grandisquamis. 

ee. Striae of scales parallel or but slightly diverging. 

/. A conspicuous humeral spot nearly equidistant from opercle and the vertical from the 
dorsal; iridescent silvery, the fins yellowish in life; A. 26-30; scales 7-33 or 34-5. 

chrysargyrea. 
//. Humeral spot much nearer opercle than dorsal; scales of the sides with a dark margin. 

A. 23 or 24; scales 5-30 to 34-3 browni. 

dd. Eye 2-2.2 in the head. 

g. No caudal spot, a vertical humeral spot; A. 28-30; scales 5-35 or 36-4 megalops. 

gg. A median caudal spot, no humeral spot; A. 26; scales 5-34-3 or 4 shideleri. 

aa. Depth 2.75 or more in the length ; three or four scales (rarely five in cotinho) between lateral line and ventrals. 
h. Caudal lobes with a median black cross-band, the base canary yellow in life, the tips white. A. 25-28; 

scales 5 or 5.5-34 to 39-3 or 3.5 dichroura. 

hit. Caudal lobes without cross-band. 

i. Upper caudal lobe black with a red or yellow spot at its base; a faint humeral spot; A. 22-27; 

scales 5-34-4 1 lepidura. 

ii. Caudal lobes alike. 

j. A very conspicuous large black caudal spot, surrounded by rusty in life. A. 20 or 21; scales 

5-32-3 to 5 cotinho. 

jj. Caudal plain. 

k. Anal rays 23-24; vertical fins tinged with red; scales 5-34-3.5 colletti. 

kk. Anal rays 1S-20; upper caudal lobe rose-colored or rusty; anal and dorsal with yellow; 
scales 5-32 to 34-3.5 copei. 

175. Mcenkhausia oligolepis (Gunther). (Plate XLVI, fig. 3.) 
Tetragonopterus tamiatus (not of Jenyns) Muller and Troschel, in Schomburgk, 

Reisen, III, 1848, 635 (trenches and swamps along the coast). 
Tetragonopterus oligolepis Gunther, Catalogue, V, 1864, 327 (British Guiana).— 

Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 53. — Ulrey, 

Ann. N. Y. Acad. Sci., VIII, 1895, 282.— Vaillant, Bull. Mus. d'Hist. Nat, 

V, 1899, 155 (Carnot). 



322 MEMOIRS OF THE CARNEGIE MUSEUM 

Moenkhausia oligolepis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III. 

1910, 437. 
Tetragonopterus agassizii Steindachner, " Ichthyologische Beitrage," v, 1876, 

41, pi. 8, fig. 2 (Tabatinga; Cudajas; Hyavary). 
? Astyanax atahualpianus Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 436, fig. 36 

(Pebas). 

I have examined the specimen marked Tetragonopterus tceniatus in Berlin. 
It is without doubt Moznkhausia oligolepis. I did not secure it along the coast, 
where Schomburgk said it was found. 

Thirty specimens, 35-96 mm. Holmia. (C. M. Cat. No. 1361a-j; I. U. 
Cat. No. 11835.) 

Eleven specimens, 39-118 mm. Aruataima Cataract. (C. M. Cat. No. 
1362a-c; I. U. Cat. No. 11836.) 

Eleven specimens, 33-53 mm. Potaro River two hours below Holmia. (C. 
M. Cat. No. 1363a-c; I. U. Cat. No. 11837.) 

Seven specimens, 28-44 mm. Savannah Landing. (C. M. Cat. No. 1364a-6; 
I. U. Cat. No. 11838.) 

Three specimens, 37-61 mm. Erukin. (C. M. Cat. No. 1365a; I. U. Cat. 
No. 11839.) 

One specimen, 88 mm. Potaro Landing. (C. M. Cat. No. 1367a.) 

Eight specimens, 40-47 mm. Tumatumari. (C. M. Cat. No. 1368a-6; I. 
U. Cat. No. 11840.) 

One specimen, 78 mm. Maripicru. (C. M. Cat. No. 1369.) 

Abundant in the Potaro both above and below the Kaieteur Falls. 

Head 3.6-4; depth 2.25 on an average; D. 11; A. usually 25 or 26; scales 5-30 
to 31-4; eye 2.5-3 in the head; interorbital wider than eye. A broad black band 
across the end of the caudal peduncle and base of caudal; distal part of all the 
caudal rays light; pink in life; a faint vertically oval humeral spot. 

176. Moenkhausia profunda sp. nov. (Plate XL VI, fig. 1.) 
Type, 51 mm. Cloaca trenches, Issorora Rubber Plantation. (Carnegie 
Museum Catalog of Fishes No. 2207.) 

Cotype, 51 mm. Same locality. (I. U. Cat. No. 12363.) 
One of the most interesting catches of the expedition. The species differs 
from Fowlerina orbicularis solely in the generic character, i. e., the absence of the 
predorsal spine. It is in all probability a derivative of orbicularis as Fowlerina 
was in all probability a derivative of the genus Moenkhausia. Of the known species 
of Moenkhausia it approaches closest to chrysargxjrea. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 323 

Head 3.8: depth 1.75; D. 11; A. 34; scales 7.5-35-7; eye .4 in snout, 2.5 
in head, 1 in interorbital. 

Deep and much compressed. For the description read that of Fowlerina 
orbicularis. 

Dorsal not reaching to adipose; anal but little emarginate, the highest ray 
reaching the seventeenth ray. 

177. Mcenkhausia grandisquamis (Muller and Troschel). (Plate XLVII, fig. 2.) 
Tetragonopterus grandisquamis Muller and Troschel, Horse Ichth., I, 1845, 27, 

pi. 8, fig. 2 (Surinam). — Gunther, Catalogue. V, 1864, 328 (British Guiana). 

-Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 281. 
Mcenkhausia grandisquamis Eigenmann, Repts Princeton Univ. Exp. Patagonia, 

III, 1910, 437. 

Fifty-one specimens, 45-79 mm. Bartica. (C. M. Cat. No. 1348a-j; I. U. 
Cat. No. 11857.) 

Sixty-six specimens, 51-86 mm. Rockstone. (C. M. Cat. No. 1349a-./; I. U. 
Cat, No. 11858.) 

Thirty-five specimens, 50-115 mm. Crab Falls. (C. M. Cat. No. 1350a-./; 
I. U. Cat. No. 11859.) 

Eight specimens, 64-110 mm. Tumatumari. (C. M. Cat. No. 1351a-c; I. U- 
Cat. No. 11860.) 

One specimen, 122 mm. Kangaruma. (C. M. Cat, No. 1352a.) 

One specimen, 55 mm. Wismar. (C. M. Cat. No. 1353a.) 

This species is also abundant in the Amazon basin. 

Head 3.5-4; depth usually 2 in the adult; D. 10 or 11; A. usually 26-28; 
scales 5-35-4; eye 2.33-2.5 in head; interorbital equal to eye, or but a trifle larger. 

A round humeral spot over the third to fifth scales of the lateral line, dis- 
appearing with age; no caudal spot in adult; sometimes a dusky area at end of 
caudal peduncle in young; a distinct silvery lateral band, the width of the free 
margin of a row of scales; fins all plain, mostly Ivyaline; sides silvery, highly 
iridescent, 

178. Mcenkhausia chrysargyrea Gunther. 
Tetragonopterus chrysargyreus Gunther, Catalogue, V, 1864, 328 (Essequibo).— 

Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 53. — Ulrey, 

Ann. N. Y. Acad. Sci., VIII, 1895, 281. 
Mcenkhausia chrysargyrea Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 437 (Tabatinga; Teffe; Jutahy; Jose Fernandez). 



324 MEMOIRS OF THE CARNEGIE MUSEUM 

Forty-three specimens, 51-61 mm. Rockstone. (C. M. Cat. No. 1370a-,/; 
I. U. Cat. No. 11841.) 

Seven specimens, 51-91 mm. Crab Falls. (C. M. Cat, No. 1371«-fr; I. U. 
Cat, No. 11842.) 

Fifteen specimens, 53-69 mm. Konawaruk. (C. M. Cat. No. 1372a-e; I. U. 
Cat. No. 11843.) 

One specimen, 58 mm. Warraputa Cataract. (C. M. Cat. No. 1366a.) 

Twenty-six specimens, 52-101 mm. Packeoo Falls. (C. M. Cat. No. 1373a-e; 
I. U. Cat. No. 11844.) 

Ten specimens, 60-87 mm. Tumatumari. (C. M. Cat. No. 1374a-c; I. U. 
Cat, No. 11845.) 

One specimen, 60 mm. Wismar. (C. M. Cat. No. 1375.) 

Two specimens, 58-60 mm. Rupununi Pan. (C. M. Cat, No. 1376; I. U. 
Cat, No. 11846.) 

Head 3.5-4; depth 2.4 in young, 2 in old; D. 11; A. 27-30; scales 7-33 to 
34-5. Eye 2.5-2.75 in head; interorbital equal to eye. 

Iridescent silvery. A deep-lying, well-defined, horizontally oval, circular, or 
rhomboidal, black spot over the space between the fifth to the eighth scale of the 
lateral line; no caudal spot. 

179. Moenkhausia browni Eigenmann. (Plate XLVII, fig. 3.) 

"Conia." 
Moenkhausia browni Eigenmann, Ann. Carnegie Mus., VI, 1909, 13; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 438. 

Type, 66 mm. Aruataima Falls, Potaro River. (Carnegie Museum Catalog 
of Fishes No. 1004.) 

Cotypes, twenty-five specimens, 46-82 mm. Holmia, Potaro River. (C. M. 
Cat. No. 1005a-e; I. U. Cat, No. 11711.) 

Cotypes, twelve specimens, 28-68 mm. Two hours below Holmia. (C. M. 
Cat. No. 1006a-c; I. U. Cat. No. 11712.) 

Cotypes, sixty-nine specimens, 23-80 mm. Savannah Landing, above Kaie- 
teur. (C. M. Cat, No. 1007a-./; I. U. Cat. No. 11713.) 

Cotype, one specimen, 31 mm. Creek below Savannah Landing, above 
Kaieteur. (C. M. Cat. No. 1008.) 

Cotypes, nine specimens, 30-62 mm. Tukeit, below Kaieteur. (C. M. ( 'at, 
No. 1009a-6; I. U. Cat, No. 11714.) 

Cotypes, two specimens, 48-50 mm. Amatuk, Lower Potaro. (C. M. Cat. 
No. 1010; I. U. Cat, No. 11715.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 325 

Cotype, one specimen, 65 mm. Tumatumari, Lower Potaro. (C. M. Cat. 
No. 1011.) 

Very similar to M. oligolepis, but without trace of caudal spot and with the anal 
falcate. 

Head 3.75-4; depth 2.3-2.6; D. 11; A. 23 or 24; scales 5-30 to 34-3; eye 2.4- 
2.5; interorbital 2.8-3. 

No caudal spot; a large, horizontally oval, humeral spot continued below to 
the origin of the pectoral; a dark band from origin of dorsal obliquely downward 
and forward to the lateral line; a dark median lateral line; white below, dark along 
back; each scale of the side with a conspicuous dark crescent along its middle. 

In life all fins but the adipose strongly tinged with red; middle of adipose 
yellow. 

This species, abundant in the Potaro River above and below the Kaieteur, 
is dedicated to the memory of C. Barrington Brown, the discoverer of this most 
beautiful fall. 

180. Mcenkhausia megalops Eigenmann. 
Tetragonopterus grandisquamis (not of Mtiller and Troschel) Ulrey, Ann. N. Y. 

Acad. Sci., VIII, 1895, 281 (Itaituba). 
Astyanax megalops Eigenmann, Proc. U. S. Nat. Mus., XXXIII, 1907, 29 (Itai- 
tuba, Brazil). 
Mcenkhausia megalops Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 438. 

One specimen, 57 mm. Rockstone. (G. M. Cat. No. 2488.) 

Head 3.6-3.7; depth 2.5-2.66; D. 9-11; A. 28-30. Scales 5-35-4; eye 2-2.2 
in head, twice as long as snout; interorbital 2.8-3 in head. 

A vertical humeral spot above the space between the third and fifth scales 
of the lateral line, faint; no caudal spot; a silvery lateral line; some metallic reflec- 
tions. 

181. Mcenkhausia shideleri Eigenmann. (Plate XLVII, fig. 4.) 
Mcenkhausia shideleri Eigenmann, Ann. Carnegie Mus., VI, 1909, 15; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 438. 

Type, 65 mm. (Carnegie Museum Catalog of Fishes No. 1012.) Bartica. 

Cotype, 73 mm. Bartica. (I. U. Cat. No. 11716.) 

Cotype, 63 mm. Tumatumari. 

This species has the largest eye of any in the genus. 

Head 3.7-3.8; depth 2.5-2.7; D. 10; A. 26; scales 5-34-3 or 4; eye 2.1 in head; 
interorbital 2.4 or 2.5 in head. 



326 MEMOIRS OF THE CARNEGIE MUSEUM 

No humeral spot ; caudal with a small, diffuse, dark spot at the base of the middle 

rays. Scales of sides margined with dark, the marginal spots tending to form dark 

lines along the sides; pigment more profuse toward the back; a series of dark spots 

on the median series of scales of the back. 

This species is named for Mr. 8. E. Shideler, volunteer assistant on the Guiana 

Expedition. 

182. Moenkhausia dichroura (Kner). 

Tetragonopterus dichrourus Kner, "Familie der Characinen," i, 1859, 41, pi. 9, 
fig. 21 (Rio Guapore; Caicara; Paraguay)- — Gtjnther, Catalogue, V, 1864, 
324.— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 53.- 
Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 279.— Perugia, Ann. Mus. 
Genova, (2a), X, 1891, 45 (Chaco Centrale). — Boulenger, Trans. Zool. Soc. 
London, XIV, 1896, 35 (San Luis and Descalvados) . — Eigenmann and Ken- 
nedy, Proc. Acad. Nat. Sci. Phila., 1903, 52 (Asuncion). 

Moenkhausia dichrourus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 438.— Eigenmann and Ward, Ann. Cam. Mus., IV, 1907, 138, PI. XL1, 
fig. 1 (Corumba, Porto Max; Asuncion). 
Two specimens, 59-62 mm. Warraputa Cataract. (C. M. Cat. No. 1345a; 

I. U. Cat, No. 11861.) 

Two specimens, 28-65 mm. Crab Falls. (C. M. Cat. No. 1346a.) 

Twelve specimens, 58-63 mm. Konawaruk. (C. M. Cat. No. 1347a-d; 

I. U. Cat. No. 11862.) 

Head about 4; depth usually 3; D. 11; A. 25-28; scales 5 or 5.5-34 to 39-3 

or 3.5; eye 2.4-2.6; interorbital slightly less than eye. 

The silvery lateral band is underlaid with a black band of the same size and 

shape. Base of caudal lobes in life bright yellow; middle caudal rays and a bar 

across the lobes black; tips of caudal lobes milk-white. 

183. Moenkhausia lepidura (Kner). 

Tetragonopterus lepidurus Kner, "Familie der Characinen," i, 1859, 40, pi. 8, 
fig. 20 (Rio Guapore). — Gtjnther, Catalogue, V, 1864, 328. — Steindachner, 
"Flussfische Siidamerika's, " iv,*1882, 32 (Tabatinga; Cudajas; Obidos; Villa 
Bella). — Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 
53.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 278.— Vaillant, Bull. Mus. 
d'Hist, Nat., V, 1899, 155 (Carnot). 

Mamkhausia lepidurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 438. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 327 

Two hundred and three specimens, 54-75 mm. Bartica. (C. M. Cat. No. 
1335a-z; I. U. Cat. No. 11825.) 

Twelve specimens, 48-71 mm. Rockstone. (C. M. Cat. No. 1336a-c; I. U. 
Cat. No. 11826.) 

Eight specimens, 42-56 mm. Cluck Island. (C. M. Cat. No. 1337a-6; 
I. U. Cat, No. 11827.) 

Fifty-one specimens, 44-80 mm. Crab Falls. (C. M. Cat, No. 1338a-.?'; 
I. U. Cat, No. 11828.) 

Twenty-two specimens, 45-58 mm. Konawaruk. (C. M. Cat. No. 1339a-e; 
I. U. Cat, No. 11829.) 

Seven specimens, 45-82 mm. Warraputa. (C. M. Cat. No. 1340a-fo; I. U. 
Cat, No. 11830.) 

Three hundred and fifteen specimens, 42-95 mm. Tumatumari. (C. M. 
Cat. No. 1341o-z; I. U. Cat, No. 11831.) 

Twenty specimens, 45-94 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1342a-e; I. U. Cat,' No. 11832.) 

Four specimens, 51-61 mm. Erukin. (C, M. Cat. No. 1343a-6; I. U. Cat, 
No. 11833.) 

Four specimens, 62-108 mm. Malali. (C. M. Cat. No. 1344a-6; I. U. Cat. 
No. 11834.) 

Head 3.75-4.4; depth 3-3.5; D. 11; A. 22-27; scales 5-34-4; eye 2.5-3, about 
equal to the interorbital. 

Base of upper caudal lobe in life conspicuously yellow or orange or cherry; 
base of lower caudal lobe, adipose fin, dorsal rays, and anal lobe less intensely yellow 
or orange; upper caudal lobe beyond the basal spot black (of varying intensity); 
a small, horizontally oval, or round, humeral spot over the second and third scales 
of the lateral line. 

184. Moenkhausia cotinho Eigenmann. 
Mcenkhausia cotinho Eigenmann, Bull. Mus. Comp. Zool., LII, 1908, 104; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 438. 

Thirty-five specimens, 34-55 mm. Wismar. (C. M. Cat. No. I312a-j; 
I. U. Cat. No. 11813.) 

Thirty-three specimens, 42-60 mm. Malali. (C. M. Cat, No. 1313a-;'; 
I. U. Cat. No. 11814.) 

Twenty-two specimens, 52-62 mm. Tukeit. (C. M. Cat. No. 1314a-6; 
I. U. Cat. No. 11818.) 

One specimen, 64 mm. Kangaruma. (C. M. Cat. No. 1315a.) 



328 MEMOIRS OF THE CARNEGIE MUSEUM 

Six specimens, 39 45-51 mm. Mud-flats below Wismar. (C. M. Cat. No. 
13160-6; I. U. Cat. No. 11815.) 

Twenty-seven specimens, 40 44-66 mm. Tumatumari. (C. M. Cat. No. 
1317a-e; I. U. Cat, No. 11812.) 

Seventeen specimens, 41 43-59 mm. Crab Falls. (C. M. Cat. No. 1318a-e; 
I. U. Cat. No. 11819.) 

Seven specimens, 12 41-57 mm. Christianburg. (C. M. Cat. No. 1319a-fe; 
I. IT. Cat, No. 11816.) 

Two specimens, 43 35 and 57 mm. Rockstone. (C. M. Cat. No. 1320«; 
I. U. Cat. No. 11817.) 

Head 3.7-3.8; depth 3+; D. 11; A. 20 or 21; scales 5-32-3.5; eye 2.75-3; 
interorbital slightly greater than eye. 

Brassy, fins dusky. A very large and very conspicuous, vertically oval, black 
spot, bordered behind with rusty or milk-white, occupies all of the base of the 
caudal. 

185. Moenkhausia colletti (Steindachner). 
Tetragonopterus collettii Steindachner, "Flussfische Slidamerika's," iv, 1882, 

33, pi. 7, fig. 3 (Obidos; Hyavary). — Eigenmann and Eigenmann, Proc. 

U. S. Nat. Mus., XIV, 1891, 53.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 

281. 
Moenkhausia collettii Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 438. 

Nineteen specimens, 43-58 mm. Wismar. (C. M. Cat, No. 1325a-e; I. U. 
Cat. No. 11804.) 

Five specimens, 34-39 mm. Malali. (C. M. Cat. No. 1326o-6; I. U. Cat. 
No. 11807.) 

One hundred and twenty-six specimens, 40-61 mm. Rockstone. (C. M. Cat, 
No. 1327o-z; I. U. Cat, No. 11810.) 

Twelve specimens, 37-59 mm. Gluck Island at Rockstone. (C. M. Cat, 
No. 1328«-c; I. U. Cat. No. 11806.) 

Five specimens, 41-56 mm. Crab Falls. (C. M. Cat. No. 1329a-6; I. U. 
Cat. No. 11808.) 

39 One of these has the lateral line interrupted. 

40 Out of twenty-four in condition to be examined two have the lateral line complete on both sides; two 
have it complete on one side; fourteen have the lateral line incomplete, developed on from eleven to twenty- 
three scales, and in the remaining six it is interrupted. 

41 Lateral line developed on from twelve to twenty scales. 

42 Lateral line developed on from nine to eleven scales. 
*» Lateral line incomplete. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 329 

Nineteen specimens, 33-46 mm. Konawaruk. (C. M. Cat. No. 1330a-e; 
I. U. Cat. No. 11803.) 

Forty-one specimens, 35-66 mm. Tumatumari. (('. M. Cat. No. 1331a-,/; 
I. U. Cat. No. 11809.) 

Over one hundred specimens, 24-68 mm. Erukin. (C. M. Cat. No. 1332a-2; 
I. U. Cat. No. 11801.) 

One specimen, 63 mm. Amatuk Cataract. (C. M. Cat. No. 1333a.) 

Three specimens, 38-40 mm. Twoca Pan, Rupununi. (C. M. Cat. No. 
1334a.) 

Head 3.7-3.8; depth 2.6-3.3; D. 11; A. 23-24; scales 5-34-3.5; eye 2.5-2.75; 
interorbital about 3 in the head. 

No caudal spot; a very narrow silvery band overlying a dark line; a well-de- 
fined humeral spot above the third, fourth, and fifth scales of the lateral line. 
Vertical fins in life more or less tinged with red. 

186. Moenkhausia copei (Steindachner). 
Tetragonopterus copei Steindachner, "Flussfische Sudamerika's," iv, 1882, 35, 

pi. 6, fig. 6 (Santarem). — Eigenmann and Eigenmann, Proc. U. S. Nat. 

Mus., XIV, 1891, 53. 
Moenkhausia copei Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

438. 

Twenty-six specimens, 30-56 mm. Wismar. (C. M. Cat. No. 1321a-e; 
I. U. Cat. No. 11824.) 

Eleven specimens, 33-56 mm. Gluck Island at Rockstone. (C. M. Cat. 
No. 1322a-c; I. U. Cat, No. 11821.) 

Fifty-three specimens, 27-55 mm. Rockstone. (C. M. Cat. No. 1323a-,/; 
I. U. Cat. No. 11820.) 

Forty-two specimens, 35-45 mm. Twoca Pan, Rupununi. (C. M. Cat. No. 
1324a-j; I. U. Cat, No. 11823.) 

Head 3.66-4; depth 3.33-3.66; D. 11; A. 18-20; scales 5-32 to 34-3.5; eye 
2.5-2.75 in the head, interorbital 3 or a little more. 

No caudal spot; a very narrow silvery band overlying a narrow dark band, 
which becomes wider in front, sometimes expanded into a humeral spot over the 
fourth scale of the lateral line; caudal rose-colored or rusty in life. 

Pristella Eigenmann. 
Pristella Eigenmann, Bull. Mus. Comp. Zool., LII, 1908, 99. 
Type, Holopristes riddlei Meek. 



330 MEMOIRS OF THE CARNEGIE MUSEUM 

This genus differs from Hemigrammus much as Hemibrycon differs from 
Astyanax. 

Lateral line incomplete; caudal scaled for at least one-third of its length; 
maxillary with teeth along nearly the entire anterior edge; gill-rakers long, setiform; 
gill-membranes free from each other and from the isthmus. 

Key to the Species of Pristella. 
a. Depth 2.3-2.75; A. 20-24; dorsal, anal, and very frequently ventral, each with a conspicuous black spot; 

no caudal spot riddlei. 

aa. Depth 3.5; A. 16-18; caudal with a spot on the base of its middle rays, other fins all plain aubynei. 

187. Pristella riddlei (Meek). (Plate XLV, fig. 3.) 
Holopristes riddlei Meek, Proc. U. S. Nat. Mus., XXIII, 1907, 11 (Los Castillas, 

Venezuela). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

437. 

Fifty-six specimens, 12-29 mm. Wismar. (C. M. Cat, No. 1307a-/; I. U. 
Cat. No. 11798.) 

Eight specimens, 37-47 mm. Georgetown trenches. (C. M. Cat. No. 
1308«-6; I. U. Cat. No. 11800.) 

Two hundred and thirty-three specimens, 26-45 mm. Botanic Garden, 
Georgetown. (C. M. Cat, No. 1309«-z; I. U. Cat, No. 11796.) 

Five specimens, Christianburg Canal. (C. M. Cat. No. 1310a; I. U. Cat, 
No. 11799.) 

Three specimens, Kumaka, Demerara River. (C. M. Cat. No. 1311a; I. U. 
Cat. No. 11797.) 

Head 3.75-4; depth about 2.3-2.75; D. 11 ; A. 20-24; scales 5-32-3, six to eight 
with pores; eye 2.64, snout 4.12, interorbital about 2.5 in the head. 

A humeral spot over the third and fourth scales of the lateral line; no caudal 
spot; dorsal, anal, and ventrals each with a conspicuous, jet-black spot; dorsal spot 
not extending upon the last ray, and leaving base and tips of rays hyaline; anal 
spot covering the third and fourth fifth of the rays forming the anterior lobe; ven- 
tral spot leaving the outer and inner rays and bases and tips of all the rays hyaline. 
Very brilliant in life, translucent, the caudal bright red, upper parts tinged with 
red, basal part of dorsal and anal lobe below the black spots bright j r ellow, the 
distal parts milk-white. 

188. Pristella aubynei Eigenmann. (Plate XLV, fig. 4.) 
Pristella aubynei Eigenmann, Ann. Carnegie Mus., VI, 1909, 24; Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 437. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 331 

Type, 50 mm. Lama Stop-Off. (Carnegie Museum Catalog of Fishes No. 
1042.) 

Cotypes, two hundred and three specimens, 20-50 mm. Lama Stop-Off. 
(C. M. Cat. No. 1043a-z; I. U. Cat, No. 11735.1 

Cotj'pes, fifty specimens, 28-46 mm. Cane Grove Corner. (C. M. Cat, 
No. 1044a-j; I. U. Cat. No. 11736.) 

Cotypes, twenty-one specimens, 35-49 mm. Maduni Stop-Off. (C. M. 
Cat. No. 1045«-e; I. U. Cat. No. 11737.) 

This species is very abundant in the canal from Cane Grove Corner to Maduni 
Creek Stop-Off. It is named for Mr. Saint Aubyne, whose guest I was at Lama 
Stop-Off, and who did everything in his power to further the interests of my fishing 
expedition. 

This species is placed in the genus with Pristella riddlei, because in the technical 
characters they agree. There is every probability that they are not immediately 
descended from the same ancestor. 

Head 3.75; depth 3.5; D. 10; A. 16-18; scales 6-31 to 33-3, rarely 4; seven to 
nine pores in the lateral line; eye 2.33; interorbital 3. 

Elongate, heavy forward; ventral profile curved more than the dorsal, which 
is nearly straight to the dorsal fin, not depressed over the eye; preventral area broad, 
rounded, postventral area keeled; predorsal area narrowly rounded. 

In life the base of the upper caudal lobe is red, that of the lower yellow, and 
there is some yellow on the under side of the caudal peduncle and in front of the 
anal. A circular spot about as large as the eye on the base of the middle caudal 
rays. A dark line in front of the dorsal, and a series of spots behind it. A well- 
defined humeral spot on and over the second and third scales of the lateral line. 

Hemigrammus Gill. 44 
Hemigrammus Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 60. 

Type, Hemigramvius unilineatus Gill. 

Small or minute Tetragonopterid characins with two rows of notched teeth 
in the upper jaw, a single row of similar teeth on the mandible, and a few teeth 
on the upper part of the maxillary; lateral line incomplete; caudal scaled. 

This genus is Mcenkhausia with an incomplete lateral line. 

Key to the Guiana Species of Hemigrammus. 
a. Dorsal with a well-defined black spot. Anal with an intense black bar from a little in front of the base of 
first ray to the tips of the fourth and fifth rays. Humeral spot vertically elongate, often faint and 

44 The account of this genus is compiled from a manuscript by Mrs. Marion Durbin Ellis. 



332 MEMOIRS OF THE CARNEGIE MUSEUM 

sometimes lacking. Second suborbital leaving a narrow naked area below. Six small, tricuspid, 
and conical teeth in the maxillary. D. 11; A. 23 to 27; scales 5-32 to 34-3 to 4.5. . . .unilineatus. 
aa. Dorsal without well-defined black markings (see also elegans). 

6. No humeral or caudal spot. Depth 3.33 to 3.75. A wide lateral streak from the middle of the caudal 
to the head and another narrower streak from above the anterior anal rays to the mandible, with- 
out- black chromatophores; the sides and back everywhere else dusky. Anal lobe and distal 
half of dorsal lobe dusky. Second suborbital about one-half as wide as the eye, without naked 
margins. Maxillary with two to four, three- to five-pointed teeth. D. 11; A. 20 to 22; scales 

5-31 to 34-3 to 3.5 erythrozonus. 

66. No humeral spot, caudal spot not as wide as the caudal peduncle, continued forward on the latter, 
faintly continuous with the lateral stripe, and continued backward only on the middle rays. No 
silvery area on the caudal peduncle. Second suborbital in contact with the preopercle. Head 
4. Maxillary with two to four conical or tricuspid teeth. D. 11; A. 22-24; scales 5-32 to 34-2 

to 3.5 rodwayi. 

666. Humeral and caudal spots both developed. Dorsal equidistant from base of middle caudal rays and 
tip of snout, or nearer the caudal. 

c. Origin of the dorsal equidistant from front of eye and caudal. Origin of the anal on the vertical 

from the last dorsal ray. Second suborbital leaving very narrow naked margins below and 
behind. Humeral spot distinct, vertically elongate, surrounded by a bright area, often 
with a second elongated spot behind the bright area. An iridescent spot on the upper half 
of the caudal peduncle. Caudal spot often continued along the edge of each caudal lobe. 
Maxillary. with two or three conical or tricuspid teeth. Depth 2.5; D. 11; A. 22 to 26; 

scales 5-30 to 33-3 to 3.5 ocellifer. 

cc. Origin of dorsal slightly nearer middle caudal rays than to tip of snout. Origin of anal on the vertical 
from the first to the third scale behind the dorsal. Caudal spot wider than long, not continued 
backward on the caudal peduncle. Humeral spot small. Maxillary with two four- or 
five-pointed teeth. Second suborbital leaving narrow naked margins below and behind. 

D. 11; A. 1.5-17; scales 5-30-3 iota. 

6666. Humeral spot present; no caudal spot. (Humeral spot sometimes faint or lacking.) 

d. Anal rays 19-26. 

e. Compressed. Depth 3.75. Humeral spot faint or diffuse, roundish. Second suborbital 
leaving narrow naked margins behind and below. Mouth moderately large. Maxillary 
equal to eye. First seven anal rays dusky. D. 11; A. 19-22; scales 5-30 to 33-3. 

Caudal not deeply scaled, three to five scales on each lobe orthus. 

ee. Subcylindrical; eye a little longer than broad, 2.25 in the head; snout comparatively long, 
3.25 in the head. Maxillary nearly straight, with three to six tricuspid or conical teeth. 

Humeral spot small and intense. D. 11 ; A. 17-20; scales 5-30 to 34-3 cylindricus. 

dd. Anal rays 12 to 14. Depth 3.2 to 3.5. Humeral spot diffuse. A wide silvery lateral stripe. Each 
dorsal scale marked with an intense dark spot. Second suborbital leaving considerable 
naked margins behind and below. Maxillary with two or three six- to seven-pointed teeth. 
D. 11; A. 12-14; scales 5-30 to 32-3 analis. 

189. Hemigrammus unilineatus Gill. (Plate XL VIII, fig. 1.) 
Pcecilurichthys hemigrammus unilineatus Gill, Ann. Lye. Nat. Hist. N. Y., VI, 
1858, 60 (Trinidad).— Gunther, Catalogue, V, 1864, 317. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 333 

Tetragonopterus unilineatus Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., 

XIV, 1891, 54.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 285 (Para, Brazil). 

—Gilbert. Proc. Wash. Acad. Sci., II, 1900, 163 (Pernambuco). 
Tetragonopterus hemigrammus unilineatus Regan, Proc. Zool. Soc. London, 1906, 

384 (Trinidad). 
Hemigrammus unilineatus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 436. 

Five specimens, 28-38 mm. Para, Brazil. (I. U. Cat. No. 5779.) 

One specimen, 40 mm. Los Castillos. (I. U. Cat. No. 10801.) 

One hundred and ten specimens, 35-48 mm. Creek in Mora Passage. (C. M. 
Cat. No. 1440a-./; I. U. Cat, No. 11898.) 

Twenty-two specimens, 31-41 mm. Creek in Barima River. (C. M. Cat. 
No. 1441a-e; I. U. Cat. No. 11899.) 

Eighty-six specimens, 23-48 mm. Aruka River. (C. M. Cat. No. 1442a-.?'; 
I. U. Cat. No. 11900.) 

Seven specimens, 32-52 mm. Issorora mud creek. (C. M. Cat. No. 1443a-6; 
I. U. Cat. No. 11901.) 

Sixteen specimens, 36-53 mm. Mud-flats in Demerara River, below Wismar. 
(C. M. Cat. No. 1444a-e; I. U. Cat. No. 11902.) 

One specimen, 37 mm. Georgetown trenches. (C. M. Cat. No. 1445a.) 

Four specimens, 41-47 mm. Wismar. (C. M. Cat. No. 1446a; I. U. Cat. 
No. 11903.) 

Five specimens, 35-47 mm. Kumaka, Demerara. (C. M. Cat. No. 1447a-6; 
I. U. Cat. No. 11904.) 

Distinguished by having an oblique black line from the base of the first to 
the tip of the fourth and fifth anal rays. Six conical and tricuspid teeth in the 
maxillary. Second suborbital leaving a narrow naked margin below. 

Head 3.75; depth 2.75-3; D. 11; A. 23-27; scales 5-32 to 34-3 to 4.5; eye 
2.25 to 2.5 in the head; interorbital narrower than the eye, 3 in the head. 

Dorsal black, except the tips of the anterior five or six rays. An oblique 
black line on the anal from the base of the first to the tips of the fourth and fifth 
rays. Humeral spot vertically elongate, often faint and sometimes lacking. No 
caudal spot. Lateral stripe narrow. Scales of the back outlined with dusky. 

190. Hemigrammus erythrozonus Durbin. (Plate XLVIII, fig. 2.) 

Hemigrammus erythrozonus Durbin, Ann. Carnegie Mus., VI, 1909, 56. — Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 



334 MEMOIRS OF THE CARNEGIE MUSEUM 

Type, 32 mm. Erukin. (Carnegie Museum Catalog of Fishes No. 1448.) 

Cotypes, thirty-two specimens, 21-33 mm. Erukin. (C. M. Cat. No. 
1449o-e; I. U. Cat, No. 11905.) 

Head 3.75; depth 3.33 to 3.75; D. 11; A. 20-22; scales 5-31 to 34-3-3.5; eye 
2.5 in head; snout two-thirds of eye. Interorbital less than eye, about 2.75 in 
head. 

No true humeral spot; pores and margins of the first three or four scales in 
the lateral line heavily outlined with dusky: a group of large chromatophores just 
behind the eye. Web of distal half of dorsal, almost all of the caudal, all of the 
ventrals and pectorals, and the web between the first seven anal rays, dusky. 
Often a faint dark spot at the base of each caudal lobe, but no true caudal spot. 
Scales of the back and upper one-third of the sides outlined with dusky. A broad 
stripe extending from the head to the caudal and half-way to the end of the middle 
caudal rays without chromatophores, cherry-red in life. Below this lateral stripe 
a dusky stripe, two scales in width, extends the length of the body. The belly and 
a streak on the sides from just above the bases of the anterior ten anal rays to the 
mandible are without chromatophores. Base of the anal and under side of the caudal 
peduncle black to dusky. Lips dusky. Dorsal lobe and upper part of the iris 
cherry-red in life. 

191. Hemigrammus rodwayi Durbin. (Plate XLVIII, fig. 3.) 

Hemigrammus rodwayi Durbin, Ann. Carnegie Mus., VI, 1909, 58. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 46 mm. Georgetown trenches. (Carnegie Museum Catalog of Fishes 
No. 1450.) 

Cotypes, one hundred and eighty-three specimens, 38-49 mm. Georgetown 
trenches. (C. M. Cat. No. 1451a-z; I. IT. Cat. No. 11906.) 

Cotypes, one hundred and twelve specimens, 28-53 mm. Botanic Garden. 
(C. M. Cat, No. 1452a-2; I. U. Cat. No. 11907.) 

Cotypes, four specimens, 24-26 mm. Mud creek in Aruka. (C. M. Cat. 
No. 1453a-6; I. U. Cat, No. 11908.) 

Cotypes, seven specimens, 34-40 mm. Creek in Barima River. (C. M. Cat, 
No. U54a-b; I. U. Cat, No. 11909.) 

Head 4; depth 2.75-3; D. 11 ; A. 22-24; scales 5-32 to 34-2.5 to 3.5; eye 2-2.33 
in head; snout two-thirds of the eye, interorbital very nearly equal to eye, 2.4 to 
2.5 in head. 

No shoulder spot. A silvery lateral stripe extends from the caudal to about 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 335 

the vertical from the first dorsal rays, and is continued forward by a few large scat- 
tered chromatophores. The black caudal spot usually extends nearly or entirely 
to the end of the middle caudal rays. Scales of the back and sides above the lateral 
stripe outlined with pigment, an olive stripe along the back. All fins somewhat 
dusky. Males with a cherry-red spot on the base of each caudal lobe; anterior 
margin of anal with a white bar, broadest towards the tip, the rest of anal and the 
base of dorsal tinged with red. Females with yellow on caudal, anal, and dorsal 
in place of the red of the males. The white bar on the anal is lacking in females. 

192. Hemigrammus ocellifer Steindachner. (Plate XLVIII, fig. 4.) 
Tetragonopterus ocellifer Steindachner, "Flussfische Sudamerika's," iv, 1882, 

32, pi. 7, fig. 5 (Villa Bella; Cudajas). — Eigenmann and Eigenmann, Proc. 

U. S. Nat, Mus., XIV, 1891, 54.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 

286 (Amazon and Solimoes basin). 
Ilolopristis ocellifer Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1903, 

145. 
Hemigrammus ocellifer Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 436. 

Thirty-three specimens, 28-44 mm. Obidos (Col. Bentos, Thayer Expedition). 
(Mus. Comp. Zool. Cat. No. 20842, part.) 

One specimen, 38 mm. Curupira (Maj. Cotinho). (Mus. Comp. Zool. Cat. 
No. 21017.) 

Sixteen specimens, 28-37 mm. Tabatinga (M. Bourget, Thayer Expedition). 
(Mus. Comp. Zool. Cat, No. 20774.) 

Five specimens, 31-36 mm. Cudajas (Thayer and Bourget). (Mus. Comp. 
Zool. Cat. No. 20969.) 

One hundred and nine specimens, 26-37 mm. Gluck Island. (C. M. Cat. 
No. 1455a-z; I. U. Cat, No. 11910.) 

Three specimens, small, Konawaruk. (C. M. Cat. No. 1456a; I. U. Cat. No. 
11911.) 

Four specimens, 28-29 mm. Malali. (C. M. Cat. No. 1157a-6; I. U. Cat. 
No. 11912.) 

Humeral spot bounded in front and behind by bright bars as wide as the spot, 
and a second, less distinct, dark bar just behind it. 

Head 3.25 to 3.5; depth 2.5 to 2.75; D. 10 or 11; A. 22 to 26; scales 5-30 to 
33-3 to 3.5; eye 2.25 to 2.5 in head; snout little more than half of eye; intcrorbital 
about equal to eye. 



336 MEMOIRS OF THE CARNEGIE MUSEUM 

Humeral spot distinct, vertically elongate, paralleled in front and behind by a 
bright bar nearly as wide as the spot; a secondary, fainter, dark bar behind the 
posterior bright bar. A black caudal spot not extending much, if at all, upon the 
middle caudal rays; a bright ring around the entire caudal peduncle. The base 
of the caudal lobes and upper part of the peduncle rusty red in life. Dorsal orange- 
tinged in life; caudal and anal rays tipped with dusky, distal third of second anal 
rays white. Anal, ventrals, and pectorals yellow in life. • Scales of the back 
outlined with pigment; a few large chromatophores scattered over the cheeks. 

193. Hemigrammus iota Durbin. (Plate XLIX, fig. 1.) 
Hemigrammus iota Durbin, Ann. Carnegie Mus., VI, 1909, 60. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 18 mm. Gluck Island. (Carnegie Museum Catalog of Fishes No. 1458.) 

Cotypes, four specimens, 19-21 mm. Rockstone. (C. M. Cat. No. 1460«; 
I. U. Cat, No. 11914.) 

Cotypes, seven specimens, 18-21 mm. Gluck Island. (C. M. Cat. No. 
1459a-6; I. U. Cat. No. 11913.) 

Head 3.6; depth 3.4; D. 11; A. 15-17; scales 5-30-3; eye 2.33-2.5; snout 
three-fifths of the eye. Interorbital slightly less than the eye, 2.8 in the head. 

Humeral spot conspicuous, black, vertically elongate, surrounded by a small 
light area; a faint secondary spot, Caudal spot variable in intensity, not extending 
upon the caudal rays, and not continuous with the narrow black lateral stripe, which 
is overlaid with silvery. Each scale of the postdorsal region marked with a round 
dark spot in addition to a few scattered chromatophores. Scales of the predorsal 
region with less distinct round spots. Scales of the sides above the lateral stripe 
outlined with dusky. Caudal in life with an orange spot on the base of each lobe. 

194. Hemigrammus orthus Durbin. (Plate XLVIII, fig. 5.) 

Hemigrammus orthus Durbin, Ann. Carnegie Mus., VI, 1909, 61. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 28 mm. Tukeit. (Carnegie Museum Catalog of Fishes No. 1477.) 

Cotypes, seventeen specimens, 22-30 mm. Tukeit, (C. M. Cat. No. 1478a-/; 
I. U. Cat. No. 11912.) 

Cotypes, twenty-five specimens, 14-21 mm. Gluck Island. (C. M. Cat. 
No. 1479a-/; I. U. Cat. No. 11922.) 

Cotype, one specimen, 27 mm. Esscquibo below Packeoo. (C. M. Cat. 
No. 1480.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 337 

Head 3.75; depth 3.75; D. 11 ; A. 19 to 22; scales 5-30 to 33-3; eye 2.5 in the 
head; interorbital not quite equal to the eye, about 3 in the head. 

A diffuse, round, or somewhat vertically elongate, humeral spot. A dark 
lateral stripe, heaviest behind the origin of the anal, but not reaching the base of 
the caudal. A black line at the base of the posterior anal rays, not continuous 
with that at the base of the first seven. Dorsal, caudal, first seven rays of the anal, 
and first two or three rays of ventrals, dusky. Scales of the back dusky, each often 
bearing a single black spot. 

195. Hemigrammus cylindricus Durbin. (Plate XLIX, fig. 3.) 

Hemigrammus cylindricus Durbin, Ann. Carnegie Mus., VI, 1909, 62. — Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 
Type, 57 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 

1461.) 

Cotypes, six specimens, 35-58 mm. Tumatumari. (C. M. Cat. No. 1462a; 

I. U. Cat. No. 11915.) 

Cotj'pes, eleven specimens, 46-54 mm. Crab Falls. (C. M. Cat. No. 1163a-c; 

I. U. Cat. No. 11916.) 

Cotypes, twenty specimens. Rockstone. (C. M. Cat. No. 1464a-e; I. U. 

Cat. No. 11917.) 

Cotype, one specimen, 45 mm. Gluck Island. (C. M. Cat. No. 1465a.) 
Head 3.3-3.66; depth 3.66-4.66; D. 11; A. 17 to 20; scales 5-30 to 34-3; eye 

large, slightly longer than wide, 2.75 in the head; interorbital almost flat, almost 

equal to the eye, 3 in the head. 

Humeral spot small, roundish or roughly triangular, often intense. A black 

line at the base of the anal. A narrow black lateral stripe. No true caudal spot) 

but sometimes a dusky spot at the base of each lobe. 

196. Hemigrammus analis Durbin. (Plate XLIX, fig. 6.) 
Hemigrammus analis Durbin, Ann. Carnegie Mus., VI, 1909, 64. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 35 mm. Rockstone. (Carnegie Museum Catalog of Fishes No. 1466.) 

Cotypes, twenty-one specimens, 24-29 mm. Gluck Island. (C. M. Cat. 
No. 1468a-e; I. U. Cat, No. 11919.) 

Cotypes, seventy-three specimens, 19-36 mm. Rockstone. (C. M. Cat, No. 
1467a-j; I. U. Cat. No. 11918.) 

Cotypes, two specimens, 29-35 mm. Wismar. (C. M. Cat. No. 1469a; I. U. 
Cat. No. 11920.) 



338 MEMOIRS OF THE CARNEGIE MUSEUM 

Head 3.5-3.75; depth 3.25-3.50; D. 11 ; A. 12-14; scales 5-30 to 32-3; eye 2.33 
in the head; snout two-thirds of the eye; interorbital less than the eye, about 
2.75 in the head. 

Humeral spot distinct but not heavy, not conspicuously elongate. Lateral 
stripe (probably red in life) the width of one scale, not so intense as the humeral 
spot, expanded on the caudal peduncle, but not extending upon the fin; scales 
overlying the lateral stripe distinctly silvery. First five anal rays, the caudal, 
and all of the dorsal, dusky. Each median dorsal scale with a roundish dark spot. 
Scales of the upper half of the sides outlined with dusky. A few chromatophores 
scattered about the base of the anal and aggregated so as to form a small dark spot 
or line on the ventral side of the caudal peduncle. 

Hyphessobrycon Durbin. 
Hyphessobrycon Durbin, Bull. Mus. Comp. Zool., LII, 1908, 100. 

Type, Hyphessobrycon compressus Meek. 

Having the characters ol Hemigrammus, but the caudal naked. 

The account of this genus is compiled from a manuscript by Mrs. Marion Durbin 
Ellis. 

Key to the Guiana Species of Hyphessobrycon. 
a. Dorsal with a well-defined black spot. 

b. Humeral spot present; anal not marked with black, or with black only on the tips of the rays. Second 

suborbital covering the entire cheek. Last few, and frequently the first few, anal rays with black 
on or near their tips. Humeral spot very small. Depth 3.8: head at base of occipital process 
three-fourths the greatest depth. Maxillary with two or three tricuspid teeth; inner row of pre- 

maxillary of five teeth. D. 11; A. 26; scales 5-32 to 34-3 minor. 

bb. Xo humeral or caudal spot; the black dorsal spot margined with white above. Maxillary with four 

to six tricuspid or corneal teeth. D. 11; A. 26 or 27; scales 5-31 to 33-3 rosaceus. 

aa. Dorsal plain. 

c. No humeral spot. 

d. A small black chevron at the base of each caudal lobe. A row of small black spots along the 
base of the anal. Maxillary with six small teeth. Ten to twelve small conical or tricuspid 
teeth in the second row of the premaxillary. D. 11; A. 19 or 20; scales 4-31-3.. .riddlei. 
dd. Caudal sometimes plain, sometimes with a faint spot. Maxillary with two minute teeth. Pre- 
maxillary with five three- to five-pointed teeth in the second row. D. 10 or 11 ; A. 17 to 24; 

scales 5-29 to 34-3.5 to 4 gracilis. 

ddd. Maxillary with two or three broad, five- to seven-pointed teeth; premaxillary with five five- to 
seven-pointed teeth in the inner row. A black lateral stripe, somewhat diffused in the 
humeral region; caudal spot continued on the middle rays, but not to their end. D. 11; A. 

16 or 17; scales 5-30 to 33-3 minimus. 

cc. Both humeral and caudal spots developed. (See also minimus.) Lower part of caudal peduncle 
dark, the upper part of the peduncle light; second suborbital broad, in contact, or nearly in 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 339 

contart, with the preopercular limb. Third anal ray not extending to the base of the last ray. 
Maxillary with five to seven very narrow conical and tricuspid teeth. D. 11 ; A. 17 to 20; scales 

6-33 to 34-4 eos. 

ccc. No caudal spot ; humeral spot vertically elongate, not continued backwards; a black line along the middle 
of the sides; mouth moderate, maxillary with three broad four- to seven-pointed teeth. D. 11; 
A. 26-31 ; scales 6-33-4 stictus. 

197. Hyphessobrycon minor Durbin. (Plate XLIX, fig. 5.) 

Hyphessobrycon minor Durbin, Ann. Carnegie Mus.. VI, 1909, 65. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 19 mm. Konawaruk. (Carnegie Museum Catalog of Fishes No. 
1189.) 

Cotypes, two specimens, 21-25 mm. Konawaruk. (I. II. Cat. No. 11767.) 

Head 3.5; depth 3.8; D. 11 ; A. 26 to 28; scales 5-32 to 34-3; eye 2.5 in the head; 
interorbital less than the eye, about 3 in the head. 

Humeral spot small, black, vertically elongate. No caudal spot. Lateral 
stripe extremely narrow and line-like, interrupted, and very faint. Scales of the 
back and upper half of the sides outlined with dusky. Dorsal with an intense 
black bar on the outer half of the anterior six or seven rajs. The tips of the second, 
third, and fourth rays, and a streak directly below the black bar, white. Last half 
of anal rays with blackish tips. Caudal, anal, ventrals, and pectorals a little dusky. 

198. Hyphessobrycon rosaceus Durbin. (Plate L, fig. 1.) 

Hyphessobrycon rosaceus Durbin, Ann. Carnegie Mus., VI, 1909, 67. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 

Type, 35 mm. Gluck Island. (Carnegie Museum Catalog of Fishes No. 
1190.) 

Cotypes, twenty-five specimens, 19-38 mm. Gluck Island. (C. M. Cat. 
No. ima-e; I. U. Cat, No. 11768.) 

Cotype, one specimen, 34 mm. Rockstone. (C. M. Cat. No. 1192a.) 

Head 3.33-3.66; depth 2.75; D. 11; A. 26 or 27; scales 5-31 to 33-3; eye 2.5 
in the head; interorbital almost equal to the eye, 2.6 in the head. 

Humeral and caudal spots lacking. Scales of the back outlined with dusky. 
The entire sides (except over the body cavity) with scattered chromatophores, 
which are a little thicker on the caudal peduncle and on the third and fourth scales 
of the lateral line and the three scales above them. The chromatophores are 
thinner over a small vertically elongate area immediately behind the humeral 
area just described. The lateral stripe is very slender, extending entirely to the 



340 MEMOIRS OF THE CARNEGIE MUSEUM 

caudal. Dorsal with a round, intensely black spot on the first seven rays, the tips 
of the second and third rays white. The distal half of the longest anal ray and the 
tip of the next ray are also white. All the fin-rays dusky. In life, with a general 
rosy tinge, especially above the anal, and the base of caudal lobes and ventrals. 
Anal lobe and base and tip of dorsal lobe bright orange. 

199. Hyphessobrycon riddlei Meek. 
Hemigrammus riddlei Meek, MS., in Eigenmann and Ogle, Proc. U. S. Nat. 

Mus., XXXIII, 1907, 13 (Los Castillos). 
Hyphessobrycon riddlei Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 436. 

One specimen, 23 mm. Rockstone. (C. M. Cat. No. 1248.) 

Depth 3.8; D. 11; A. 20; scales 4-31-3; eye 3 in the head. 

Frontal fontanel triangular, very small, narrower than the parietal, and half 
the length of the latter without the occipital groove. Second suborbital in con- 
tact with the preopercle. Mouth small; maxillary very little shorter than the 
eye, about 3 in the head, with six conical teeth; premaxillary with twelve small 
teeth in the inner row and two in the outer. 

Lateral line with pores on the anterior half of the scales. 

Origin of the dorsal equidistant between the snout and the caudal. Origin 
of the anal on the vertical from the first scale behind the dorsal; anal slightly falcate. 

A small dark spot at the base of each caudal lobe, and a row of small black spots 
along the base of the anal; no humeral spot; no fin markings. 

200. Hyphessobrycon gracilis (Reinhardt). (Plate XLIX, fig. 4.) 
Tetragonopterus gracilis Reinhardt, in Liitken, Overs. Dan. Vidensk. Selsk. 

For., 1874, 133 (Lagoa Santo).— Lutken, Vidensk. Selsk. Skr., (5), XII, 

1875, 217, pi. 5, fig. 16 (Rio das Velhas). — Eigenmann and Eigenmann, Proc. 

U. S. Nat. Mus., XIV, 1891, 53.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 

286.— Boulenger, Boll. Mus. Zool. ed. Anat. Comp. Torino, X, 1895, 3 (Villa 

Rica) . 
Hemigrammus gracilis Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXVIII, 

1907, 15 (Lagoa Santa). 
Hyphessobrycon gracilis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 436. 
Tetragonopterus schniardce Ulrey (not of Steindachner), Ann. N. Y. Acad. Sci., 

VIII, 1895, 286 (Para). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 341 

Nineteen hundred and seventy-seven specimens, 24-30 mm. Dr. Justa, Brazil 
(Maj. Cotinho, Thayer Exp.). (Mus. Comp. Zool. No. 21008.) 

Four specimens, 20-24 mm. Pani, Brazil. (I. U. Cat. No. 5176.) 
One specimen, 27 mm. Lower Amazon. (I. U. Cat. No. 5177.) 
One specimen, 44 mm. Iga (James). (Mus. Comp. Zool. No. 20812.) 
Sixteen specimens, 19-24 mm. Gluck Island. (C. M. Cat, No. 1247; I. U. 
Cat. No. 11772.) 

Head 3-3.5; depth 3-3.5; D. 10, occasionally 11; A. 17-24; scales 5-29 to 
34-3.5 or 4, six to thirteen pores in the lateral line; eye 2-2.5 in the head; inter- 
orbital little less than the eye, 2.7-3 in the head. 

All of the fins hyaline, except for the occasional dim spot at the base of the 
caudal, which never reaches the end of the caudal rays. A distinct silvery lateral 
stripe subtending a very inconspicuous, narrow, brown, or black stripe. The 
scales, especially those of the lateral line and the series above and below it, are 
iridescent. 

201. Hyphessobrycon minimus Durbin. (Plate XLIX, fig. 2.) 
Hyphessobrycon minimus Durbin, Ann. Carnegie Mus., VI, 1909, 68. — Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 436. 
Type, 18 mm. Cane Grove Corner. (Carnegie Museum Catalog of Fishes 
No. 1193.) 

Cotypes, 16-21 mm. Cane Grove Corner. (I. U. Cat. No. 11769.) 
Head 3.33-3.66; depth 3.5-3.75; D. 11; A. 16 or 17; scales 5-30 to 33-3; 
eye 2+ in head; snout less than eye; interorbital less than eye, about 3 in head. 

Caudal spot intensely black, roundish, and scarcely, if at all, continued upon 
the caudal rays. Humeral spot lacking, but the intense narrow black lateral 
stripe widened somewhat in the humeral region. Scales of the back and sides, above 
the lateral stripe, heavily outlined with dusky. Fins without distinct markings of 
black or white. Sides over and below the lateral stripe marked with iridescent 
steel-blue. Preopercle also with blue iridescence. 

202. Hyphessobrycon eos Durbin. (Plate L, fig. 2.) 
Hyphessobrycon eos Durbin, Ann. Carnegie Mus., VI, 1909, 69. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 437. 

Type, 36 mm. Creek between Potaro Landing and Kangaruma. (Carnegie 
Museum Catalog of Fishes No. 1194.) 

Cotypes, twenty-four specimens, 35-42 mm. Creek between Potaro Landing 
and Kangaruma. C. M. Cat. No. 1196a-e; I. U. Cat, No. 11770.) 



342 MEMOIRS OF THE CARNEGIE MUSEUM 

Cotypes, forty-three specimens, 19-34 mm. Tukeit. (C. M. Cat. No. 
1195a-j; I. U. Cat. No. 11771.) 

Head 3.25-3.33; depth 2.5-2.7; D. 11; A. 17-20; scales 6-33 or 34-4; eye 2.5 
in the head; snout about 2 in the eye; interorbital almost equal to the eye, 2.75 
in the head. Maxillary teeth mostly conical, largest teeth with never more than 
three points. Maxillary equal to the eye. 

Humeral spot very faint, vertically elongate, very near the head. Lateral 
stripe narrow and very indistinct. Caudal spot intensely black, covering the ven- 
tral two-thirds of the caudal peduncle, a little narrower in front than on the ver- 
tical from the origin of the lower caudal lobe, not extending upon the caudal rays. 
Top of head and dorsal scales very dark; scales of upper half of the sides heavily 
outlined with dusky. All fin-webs dusky. Numerous chromatophores scattered 
over the rest of the body, especially large and prominent on the cheeks. 45 Anterior 
half of anal, base of anal, sides just above the anal, and ventrals reddish; caudal 
red or orange to deep yellow, lower lobe often more colored than the upper one; 
base of dorsal, pectorals, cheeks, and under part of head yellow. 

203. Hyphessobrycon stictus Durbin. (Plate XLIX, fig. 7.) 

Hj/phessobrycon stictus Durbin, Ann. Carnegie Mus., VI, 1909, 71. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 437. 

Type, 38 mm. Lama Stop-Off. (Carnegie Museum Catalog of Fishes No. 
1197.) 

Cotypes, one hundred and eight specimens, 25-40 mm. Maduni Creek. 
(C. M. Cat, No. 1435a-j; I. U. Cat. No. 11895.) 

Cotypes, one hundred and sixteen specimens, 22-39 mm. Lama Stop-Off. 
(C. M. Cat. No. 1436a-/.; I. U. Cat. No. 11896.) 

Cotype, one specimen. Rockstone. (C. M. Cat. No. 1437.) 

Cotypes, ten specimens. Christianburg Canal. (C. M. Cat, No. 1438a-e; 
I. U. Cat, No. 11897.) 

Cotype, one specimen. Cane Grove Corner. (C. M. Cat. No. 1439.) 

Head 3.5-3.8; depth 2.75-3.25; D. 11; A. 26-31; scales 6-33 to 35-4; eye 2.25 
in head; snout 2 in eye; interorbital less than eye, about 2.5 in head. 

Humeral spot round, very intense, surrounded by a light ring, very frequently 
with a less intense dark bar extending obliquely downward and forward, and an- 
other shorter one extending obliquely upward and forward. A faint secondary 
humeral spot the width of two scales behind the first. Lateral stripe sharp and 

45 All specimens at hand were preserved in formalin and so have the black pigment emphasized. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 343 

very narrow, not reaching the caudal; no caudal spot. Dorsal scales outlined with 
dusky. Top of head very thickly covered with chromatophores. Fins all a little 
dusky. Sides silvery, iridescent. Caudal peduncle to in front of adipose, the 
adipose and caudal (except the lobes) very rich cherry-red. Caudal lobes, anal, 
and dorsal canary-yellow. 

Dermatocheir Durbin. 
Dermatocheir Durbin, Ann. Carnegie Museum, VI, 1909, 55. 

This genus differs from its nearest relative, Hyphessobrycon, in having an archaic 
pectoral like Archicheir. The pectoral consists of a fleshy lobe, surrounded by a 
fringe of filaments. 

Type, Dermatocheir catablepta Durbin. 

204. Dermatocheir catablepta Durbin. 
Dermatocheir catablepta Durbin, Ann. Carnegie Mus., VI, 1909, 55. — Eigenmann, 

Repts. Princeton Univ. Exp. Patagonia, III, 1910, 437. 

Type unique, 18 mm. Tumatumari, above the falls. (Carnegie Museum 
Catalog of Fishes No. 1198.) 

Head 3.5; depth 3.8; D. 11; A. 20; scales 5-33-3; eye 2.5 in the head; inter- 
orbital very slightly greater than the eye, 2.2 in the head. 

Humeral spot vertically elongate, very faint. No caudal spot, but a few 
chromatophores at the base of each caudal lobe. Lateral stripe very dim. Scales 
of the back outlined with dusk}'. Fins without pigment. 

Creatochanes Gtinther. 
Creatochanes Gunther, Catalogue, V, 1864, 318, 329. 

Type, Salmo melanurus Bloch. 

Elongate, spindle-shaped fishes, but slightly compressed, reaching a length of 
157 mm. The species are very similar and have the following characters in common : 
premaxillary with a distinct antero-posterior extent meeting the anterior portion 
of the maxillary at a nearly right angle; maxillary long, slipping under the first 
suborbital, as well as under the preorbital, its anterior margin greatly arched above, 
straight, or nearly so, below; mouth large, the lower jaw freely movable; tongue but 
little free, fleshy. Snout and maxillary much more than half the head in length. 

Lower jaw included, with five or six large equal teeth in front, each with a 
long median and several minute lateral cusps, the lateral teeth somewhat recurved 
and followed by a series of minute teeth. Premaxillary with five or six multicuspid 
incisor teeth in the inner row; teeth of the outer row narrower; maxillary with two 
multicuspid teeth. 



344 MEMOIRS OF THE CARNEGIE MUSEUM 

Gill-membranes free from the isthmus; gill-rakers about -5-10. 

Lateral line complete, (Jecurved; a very narrow sheath composed of one series 
of minute scales along the bases of the first ten anal rays. Caudal lobes entirely 
naked; preventral region broadly rounded; predorsal and preventral areas each 
with a median series of scales; postventral area compressed; dorsal and ventrals 
equidistant from tip of snout; origin of anal entirely behind dorsal; adipose fin 
slightly in advance of end of anal; pectorals not or scarcely to ventrals; ventrals 
not to anal, with a small axillary scale. 

Alimentary canal about equal to the length (without the caudal), with eleven 
large cceca; air-bladder large, the posterior portion more than twice as long as the 
anterior, not quite reaching anal. 

Key to the Guiana Species of Creatochanes. 
a. Maxillary extending to end of the second suborbital, its tip and posterior margin of pupil equidistant from 
tip of snout; suture between first and second suborbital usually extending down and back; second 
suborbital short, its anterior margin continued as one convex curve to the angle; normally seven, 
rarely eight, rows of scales between the lateral line and the dorsal; stria' of scales when present nearly 
parallel. 
b. Caudal lobes dark, the upper darkest, with water-marks; basal spot of upper caudal lobe, as well 
as dorsal and anal rays, yellow; pectorals not reaching ventrals; second tooth of the pre- 
maxillary in line with the rest or moved forward; lateral stripe (in formalin specimens) dimin- 
ishing in front of the dorsal, not continued to the head; very highly iridescent. Head 3.8-4; 

depth 3.75; D. 11; A. 26-29; scales 7-44 to 47-2.5 or 3 affinis. 

bb. Caudal lobes plain, a broad black band on about eight rays of the caudal, counting from the second be- 
low the middle upward, margined with red above and below; pectorals just reaching ventrals; 
second tooth in line with the rest or slightly withdrawn. Head 4-4.25; depth 3.4-3.5; D. 11; 
A. 27-29; scales 7-44 to 46 (usually 45)-3; eye 2.4-3; interorbital a little greater or a little less 

than eye; maxillary with one or two teeth melanurus. 

an. Maxillary not extending to end of second suborbital, its tip and middle of eye equidistant from tip of 
snout; suture between first and second suborbital vertical; lower jaw shorter; anterior margin of second 
suborbital not forming a simple convex curve to the angle above the angle of the preopercle. Nor- 
mally six, very rarely seven, scales between the lateral line and the dorsal; upper caudal spot, as 
well as dorsal and anal rays, red; middle caudal rays and upper lobe beyond the red spot black, with 
water-marks; second tooth of the front row of the premaxillary withdrawn; pectorals shorter than in 
affinis, not reaching the ventrals; lateral stripe (in formalin specimens) continued to the head; less 
highly iridescent in life than affinis. Head 4.66-4.75; depth 3.4-3.8; D. 11 ; A. usually 31 (28-31); 
scales 6-45 or 46-3; articulation of lower jaw slightly in advance of the suture between the first and 
second suborbital; maxillary teeth 0-2 caudomaculatus. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 345 

205. Creatochanes affinis Gunther. (Plate L, fig. 3.) 

"Corwi" or "Kowi" of the Wacusi Indians. 

Tctragonopterus affinis Gunther, Catalogue, V, 1864, 327 (British Guiana).— 

Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 278.— Vaillant, Bull. Mus. d'Hist. 

Nat,, V, 1899, 154 (Carsevenne and Carnot). 
Bryconops {Creatochanes) melanurus (not of Bloch) Muller and Troschel, in 

Schomburgk, Reisen, III, 1848, 635 (Rupununi). — Steindachner, " Chara- 

cincn des Amazonenstromes," SB. Akad. Wiss. Wien, LXXXI, 1875, 14, fig. 

7 (Obidos; Rio Tapajos). 
Creatochanes affinis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 435. 

Nine specimens, 70-105 mm. Aruataima. (C. M. Cat. No. 1400a-c; I. U. 
Cat, No. 11874.) 

Twenty-nine specimens, 38-109 mm. Holmia. (C. M. Cat. No. 1401a-e; 
I. U. Cat. No. 11875.) 

Eighteen specimens, 34-83 mm. Two hours below Holmia. (C. M. Cat. 
No. 1402a-e; I. U. Cat. No. 11876.) 

Eight specimens, 29-96 mm. Savannah Landing. (C. M. Cat. No. 1403a-6; 
I. U. Cat. No. 11877.) 

Twenty-seven specimens, 53-124 mm. Tukeit, (C. M. Cat, No. 1404a-e; 
I. U. Cat. No. 11878.) 

Six specimens, 32-62 mm. Amatuk. (C. M. Cat. No. 1405a-6; I. U. Cat, 
No. 11879.) 

Five specimens, 46-102 mm. Creek below Potaro Landing. (C. M. Cat. 
No. U06a-b; I. U. Cat, No. 18880.) 

Forty-seven specimens, 54-101 mm. Tumatumari. (C. M. Cat. No. 1407a 
-6; I. U. Cat, No. 11881.) 

Five specimens, 83-96 mm. Christianburg. (C. M. Cat. No. 1407a; I. U. 
Cat, No. 11882.) 

One specimen, 30 mm. Wismar. (C. M. Cat, No. 1408.) 

One specimen, 58 mm. Warraputa. (C. M. Cat. No. 1409.) 

Two specimens, 80-90 mm. Konawaruk. (C. M. Cat. No. 1410; I. U. Cat. 
No. 11883.) 

One specimen, 50 mm. Bartica. (C. M. Cat. No. 1411.) 

Thirty specimens, 45-88 mm. Maripicru, branch of the Ireng. 46 (C. M. Cat. 

No. 1412a-;; I. U. Cat. No. 11884.) 

46 Caudal lobes and middle rays uniformly black, bases of both lobes cherry-red or orange. Nineteen 
other specimens were received from a tributary of the Ireng, the name of which was not legible. 



346 MEMOIRS OF THE CARNEGIE MUSEUM 

206. Creatochanes melanurus (Bloch). (Plate L, fig. 4.) 
Salmo melanurus Bloch, Ausl. Fische, VIII, 1794, pi. 381, fig. 2 (Surinam). 
Tetragonopterus melanurus Muller and Troschel, Horse Ichth., I, 1845, 14 

(Surinam). — Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 155. 

— Gunther, Catalogue, V, 1864, 329 (British Guiana; Essequibo); Proc. Zool. 

Soc. London, 1868, 247 (Surinam). — Eigenmann and Eigenmann, Proc. U. S. 

Nat. Mus., XIV, 1891, 56.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 274. 
Creatochanes melanurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 435. 

Bloch had three specimens which served him as types of melanurus, two of 
which belonged to this species, and one to caudomaculatus. The one figured was 
doubtless the one here called melanurus. 

Fourteen specimens, 36-124 mm. Malali. (C. M. Cat. No. 1393a-/; I. U. 
Cat. No. 11886.) 

Eighty-one specimens, 43-138 mm. Wismar. (C. M. Cat. No. 1394a-j; I. 
U. Cat. No. 11887.) 

Fifteen specimens, 70-95 mm. Christianburg. (C. M. Cat. No. 1395a-e; 
I. U. Cat. No. 11888.) 

Eighteen specimens, 26-100 mm. Christianburg Canal. (C. M. Cat. No. 
1396a-e; I. U. Cat, No. 11889.) 

Fifteen specimens, 63-84 mm. Near Freiheit, (C. M. Cat. No. 1397a-e; 
I. U. Cat. No. 11890.) 

Twenty-nine specimens, 33-129 mm. Lama Stop-Off. (C. M. Cat. No. 
1398a-e; I. U. Cat, No. 11891.) 

Ten specimens, 52-68 mm. Maduni Creek. (C. M. Cat. No. 1399a-c; I. 
U. Cat, No. 11892.) 

Readily distinguished by its eccentric black caudal band. It differs from 
C. affinis in the characters mentioned in the key. 

This species is abundant in the Demerara River and Mahaica Creek basin to 
the coast. I did not find it in the parts of the Essequibo examined. 

207. Creatochanes caudomaculatus Gunther. (Plate L, fig. 5.) 

Salmo melanurus Bloch, Ausl. Fische, VIII, 1794, 84, PI. 381, fig. 2, part (Surinam). 

Tetragonopterus caudomaculatus Gunther, Catalogue, V, 1864, 330 (South Amer- 
ica).— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 278. 

Creatochanes caudomaculatus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 
III, 1910, 435. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 347 

Ten specimens, 51-84 mm. Malali. (C. M. ( 'at. No. 1382a-c; I. U. Cat, No. 
11867.) 

Seven specimens, 68-94 mm. Mud-flats below Wismar. (C. M. Cat. No. 
1383a-&; I. U. Cat. No. 11868.) 

Two specimens, 109-125 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1384a; I. U. Cat. No. 11869.) 

Two hundred and sixty-nine specimens, 40-120 mm. Tumatumari. (C. M. 
Cat. No. 1385a-z; I. U. Cat. No. 11866.) 

Nine specimens, 38-60 mm. Konawaruk. (C. M. Cat. No. 1386o-6; I. U. 
Cat. No. 11870.) 

Fifty-six specimens, 27-89 mm. Crab Falls. (C, M. Cat, No. 1387a-,/'; 
I. U. Cat. No. 11865.) 

One specimen, 85 mm. Rockstone. (C. M. Cat. No. 1388.) 

Twenty specimens, 22-50 mm. Cluck Island. (C. M. Cat, No. 1389a-/; 
I. U. Cat. No. 11864.) 

Twenty-one specimens, 55-71 mm. Bartica. (C. M. Cat. No. 1390a-/; 
I. U. Cat. No. 11871.) 

Two specimens, 69-70 mm. Koriabo Rubber Plantation. (C. M. Cat. No. 
1391; I. U. Cat. No. 11872.) 

Eleven specimens, 43-54 mm. Mora Passage. (C. M. Cat. No. 1392a-c; 
I. U. Cat. No. 11873.) 

This species is most readily distinguished from the other species of the genus 
by its short maxillary, the number of scales in the lateral line, and the red caudal 
spot, 

Creagrutus Giinther. 
Creagrutus Gunther, Catalogue, V, 1864, 339. 

Type, Creagrutus mulleri Gunther. 

Minute fishes with the teeth of the lower jaw in a single series, those on the 
premaxillary in three series; anal short, of not more than fourteen rays; lateral 
line complete; caudal naked. 

208. Creagrutus melanzonus Eigenmann. (Plate XLV, fig. 1.) 

Creagrutus melanzonus Eigenmann, Ann. Carnegie Mus., VI, 1909, 30; Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 435. 

Type, 44 mm. Crab Falls. (Carnegie Museum Catalog of Fishes No. 1067.) 
Cotypes, two specimens, 27 mm. Warraputa. (C. M. Cat, No. 1068; I. U. 

Cat. No. 11753.) 



348 MEMOIRS OF THE CARNEGIE MUSEUM 

Cotypes, three specimens, 25 to about 38 mm. Tumatumari. (C. M. Cat. 
No. 1069; I. IT. Cat, No. 11754.) 

Head 4; depth 4.33; D. 10; A. 11; scales 6-36-2.5; eye 2.6; interorbital 3.5. 

Elongate, heaviest above middle of pectoral, the width about one-half the 
depth; preventral area broadly rounded, postventral rounded; predorsal area broad, 
with an obscure keel; a median series of about ten scales. 

Occipital process very short, about one-seventh of the distance of its base from 
the dorsal; skull smooth, but slightly convex; frontal fontanel triangular, nearly 
as long as the parietal; mouth rounded, projecting beyond the lower jaw; cheeks 
long and low, the second suborbital about twice as long as broad, its convex margin 
leaving a considerable naked area, except at a point of contact with the lower limb 
of the operculum. 

Maxillary-premaxillary border forming a simple, concave curve; horizontal 
extent of the premaxillary about equal to the length of the maxillary, which is 
equal to half the length of the eye. Nine teeth in each premaxillary, those in the 
maxillary similar and continuous with the last of the premaxillary teeth; outer 
teeth of the premaxillary conical, inner tricuspid; about seven tricuspid teeth in 
the dentary, of which the first three are large, the rest minute; tips of all the teeth, 
except those of the maxillary and those of the sides of the lower jaw, brown. Lower 
jaw short, less than length of eye. 

Gill-rakers 4 + 10. 

Scales very thin; anal sheath none; caudal lobes naked, except for a few large 
scales on the lower lobe; axillary scale well-developed. 

Origin of dorsal in advance of the middle ; origin of ventrals scarcely in advance 
of that of the dorsal ; origin of anal behind the last ray of the dorsal; adipose slightly 
behind base of last anal ray; ventrals not reaching anal; pectorals not nearly to 
ventrals. 

Straw-colored, with a bright silvery band; first suborbital, cheeks and opercle 
behind eye, snout, and upper part of head dotted. A continuous curved band 
crossing third and fourth scale of the lateral line ; scales of the back margined with 
one to several series of dots; silvery lateral band underlaid with a dotted stripe ; 
a small caudal spot. 

Bryconamericus Eigenmann. 

Bryconamericus Eigenmann, Ann. Carnegie Mus., IV, 1907, 139 (exodon). 

Type, Bryconamericus exodon Eigenmann. 

This genus is an Astyanax with the front rows of teeth of the premaxillary 
usually in a wavy line, not parallel with the line of the second row, which is com- 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 349 

posed of but four teeth. D. 9 or 10, rarely 11; second suborbital expanded, cov- 
ering the entire space between the eye and the lower limb of the preopercle; no 
naked area below the surface of the first and second suborbitals. Maxillary with 
not more than five teeth on its upper anterior edge; caudal naked. 
A single species has been taken in Guiana. 

209. Bryconamericus hyphessus Eigenmann. (Plate XLV, fig. 2.) 

Bryconamericus hyphesson Eigenmann, Ann. Carnegie Mus., VI, 1909, 32; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 434. 

Type, 37.5 mm. Tumatumari, Lower Potaro. (Carnegie Museum Catalog 
of Fishes No. 1070.) 

Cotypes, ten specimens, 34-3G mm. Tumatumari. (C. M. Cat. No. 1071a-6; 
I. U. Cat. No. 11755.) 

Most closely related to stramineus. 

Head 4.5; depth 4; D. 9; A. 16; scales 4-36-2; eye 2.66-2.75; interorbital 
equal to eye. 

Slender, but compressed, greatest depth over tip of pectorals; ventral and 
dorsal outlines equally arched; preventral area rounded, with normal scales; post- 
ventral area short, compressed; predorsal area rounded, with a regular series of 
ten scales. 

Occipital process very short, only about one-eighth of the distance between its 
base and the dorsal, bordered by two scales on the sides; skull convex, smooth, a 
groove above the eye just within the orbital rim; frontal fontanel very short, tri- 
angular, not half as long as the parietal; snout blunt, the lower jaw included; 
mouth small, the maxillary a little more than half the length of the eye; cheeks not 
very wide, entirely covered by the second suborbital; maxillary with three or four 
broad, five-pointed teeth; premaxillary with two series of five-pointed teeth, four 
teeth in the inner row, four to six in the outer, the teeth of the outer row smaller 
than those of the inner row, the inner series parallel with the outer, except that the 
third tooth is withdrawn from the line of the rest; dentary with seven or eight 
graduated, five-pointed incisors. 

Scales very regularly imbricate, without interpolated or omitted scales; about 
three scales on the base of each caudal lobe; scales of the sides usually without, 
those of the tail sometimes with a single ridge or line; anal sheath very narrow, 
consisting of a single series of minute scales extending along the greater part of the 
base of the fin ; lateral line decurved. 

Origin of dorsal a little behind the middle of the body, over the middle of the 



350 MEMOIRS OF THE CARNEGIE MUSEUM 

ventrals; highest dorsal ray 4.5 in the length; adipose fin behind the vertical from 
the base of the last anal ray ; caudal forked, the longest rays a little greater than the 
depth; anal slightly emarginate; ventrals reaching anal, pectorals to ventrals, or 
but a trifle shorter. 

Hyaline; a conspicuous silvery lateral band; sides of head silvery; a vertical 
humeral spot crossing the second scale of the lateral line; three parallel dark lines 
along the middle of the back; scales of the back margined with several rows of 
chromatophores; chromatophores along base of anal and scattering ones on the 
sides, a band of chromatophores below the silvery band ; a narrow dark band from 
the tip of the first (short) dorsal ray to the tip of the penultimate, tips of the longer 
raj r s and bases of all the rays hyaline; caudal everywhere punctate, except at the 
tips of the rays and a triangular patch adjoining the middle rays above and below, 
these parts hyaline; tips of highest anal rays milky; tips of the other rays dark, 
the dark color continued across the longest rays at the same level; pectorals and 
ventrals more or less dotted. 

210. Astyanax Baird and Girard. 

Astyanax Baird and Girard, Proc. Acad. Nat. Sci. Phila., 1854, 26. 

Type, Astyanax argentatus Baird and Girard. 

Small Tetragonopterids with two series of teeth in the premaxillary, five or 
more teeth in the inner series; a single series in the mandible, those on the sides 
being abruptly smaller; a few teeth on the maxillary; lateral line complete, but little 
decurved; caudal naked, predorsal line scaled; anal short or moderate, its origin 
behind that of the dorsal; preventral area with normal scales; second suborbital 
leaving a narrow naked area. 

Key to the Guiana Species of Astyanax. 
a. Caudal spot minute or none. 

6. A. 25-27 ; scales 34 or 35 guianensis. 

bb. A. 20-22 ; scales 33-35 essequibensis. 

na. A large caudal spot. 

c. A vertical humeral spot; a definite, oval caudal spot. A. 21-24; lateral line 33-35 mutator. 

cc. A large, definite, horizontal, parabolic humeral spot; a diffuse caudal spot; A. 25-26; lateral line 34-35; 

depth 2.3-2.6 mucronatus. 

cce. A large, horizontal humeral spot; depth 3 wappi. 

211. Astyanax guianensis Eigenmann. (Plate LI, fig. 1.) 

Astyanax guianensis Eigenmann, Ann. Carnegie Mus., VI, 1909, 10; Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 434. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 351 

Type, 54 mm. Warraputa. (Carnegie Museum Catalog of Fishes No. 1013.) 

Cotypes, one hundred and seven ty-six specimens. Rockstone. (C. M. Cat. 
No. 10Ua-z; I. U. Cat. No. 11717.) 

Cotypes, two specimens, 45-52 mm. Crab Falls. (C. M. Cat. No. 1015; 
I. U. Cat. No. 11718.) 

Cotypes, two specimens, 50-55 mm. Warraputa. (C. M. Cat. No. 1016; 
I. U. Cat, No. 11719.) 

Cotypes, thirty-four specimens, 43-55 mm. Tumatumari. (C. M. Cat. No. 
1017a-,/; I. U. Cat, No. 11720.) 

Allied to .4. multidens, but without a caudal spot, 

Head 4; depth 2.6-3; D. 10 or 11; A. 25-27; scales 5-34 or 35 (rarely 36)-4; 
eye 2.33; interorbital 3. 

Compressed, subrhomboidal; ventral profile regularly arched; dorsal profile 
with an angle at the origin of the dorsal, slightly depressed over the eye; preventral 
area rounded, tending to flattish, with a median series of scales, sometimes irregular 
in the middle; post ventral area narrowly rounded; predorsal area rounded, with a 
median series of nine scales. 

Occipital process about 4 in the distance from its base to the dorsal, bordered 
by three scales on the sides; interorbital flat, with marginal grooves; frontal fontanel 
shorter, triangular; second suborbital covering the entire cheek, with the exception 
of a triangular area below the junction between the first and second suborbitals; 
maxillary much shorter than the eye, 3 in the head; four or five teeth in the first 
row of the premaxillary, if five, the third very slightly out of line with the others; 
five graduated teeth in the second row, their denticles arranged in a slight crescent; 
four to seven teeth in the maxillary ; mandible with four large teeth, and abruptly 
smaller ones on the sides. 

Scales everywhere regularly imbricate, no omitted or interpolated scales; 
each scale of the side with from two to eight diverging stria? ; anal sheath of very few 
scales in a single series along the base of the anterior rays; a few scales on the base 
of the caudal lobes. 

Ventrals slightly nearer to the snout than to the dorsal; origin of the dorsal in 
advance of the middle, its highest ray 3.25 in the length; anal deeply emarginate, 
the second and eleventh rays reaching the base of the eighteenth; ventrals reach- 
ing anal, pectorals slightly beyond ventrals. 

Opercle dusky; a dark vertical band crossing the third to the sixth scales behind 
the head; a dusky streak below origin of dorsal; sides behind this profusely dotted; 
margins of scales of the sides of the abdomen with a few color-cells; very few cells 



352 MEMOIRS OF THE CARNEGIE MUSEUM 

on the cheeks; base and tip of dorsal hyaline, the middle with chromatophores; 
adipose dotted; caudal nearly uniformly dotted, a small area at base of each lobe 
free from chromatophores; anal lobe and a streak through its middle free from pig- 
ment; ventrals and pectorals practically free from pigment. 

212. Astyanax essequibensis Eigenmann. (Plate LI, fig. 2.) 

Astyanax essequibensis Eigenmann, Ann. Carnegie Mus., VI, 1909, 17; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 434. 

Type, 53 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 
1018.) 

Cotypes, ninety-six specimens, 40-68 mm. Tumatumari. (C. M. Cat. Xo. 
1019a-z; I. XL. Cat, No. 11721.) 

Cotype, one specimen, 44 mm. Bartica. (C. M. Cat. No. 1020.) 

Cotypes, three specimens, 41-48 mm. Rockstone. (C. M. Cat. No. 1021a; 
I. U. Cat. No. 11723.) 

Cotypes, seventy-five specimens, 39-57 mm. Crab Falls. (C. M. Cat. No. 
1022a-z; I. U. Cat. No. 11723.) 

Allied to A. paucidens, but having a well-developed humeral spot. 

Head about 4; depth 3.33; D. 11; A. 20-22; scales 5-33 to 35-4; eye 2.3; 
interorbital 3. 

Elongate, the ventral profile regularly arched; dorsal profile with an angle at 
the origin of the dorsal, not depressed over the eye; preventral area flat, postcen- 
tral narrowly rounded; predorsal area rounded, with a median series of eight or 
nine scales. 

Occipital process about one-fifth of the space from its base to the dorsal, bordered 
by three scales; interorbital nearly flat, with marginal grooves; frontal fontanel 
narrow, longer than the parietal; second suborbital leaving a triangular naked area 
below its junction with the first; maxillary 3 in the head; premaxillary with two to 
four teeth in the front series, which is parallel with the second series; five teeth in 
the second row, their denticles arranged in a distinct crescent ; maxillary with three 
teeth; mandible with four graduated teeth and abruptly smaller ones on the sides. 

Scales as in A. guianensis, but fewer scales on the base of the caudal lobe. 

Dorsal and ventrals equidistant from tip of snout; highest dorsal ray about 
3.75 in the length; origin of dorsal about equidistant from tip of snout and tip of 
adipose; anal emarginate; ventrals not quite reaching anal; pectorals to ventrals. 

Highly iridescent, a few chromatophores on cheek and opercles; an oblique 
dark band crosses the second, third, and fourth scales of the lateral line, another 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 353 

one parallel to it in front of the dorsal shades into the thickly punctate sides; a 
punctate band extends from the base of the first dorsal ray to the tips of the seventh 
and eighth; tip of adipose black; a minute spot at the base of the middle caudal 
rays, their tips dusky, all of the membranes punctate; a punctate band from the 
middle of the first anal rays along the tips of the rest of the rays, other parts of 
the fin hyaline; pectorals and ventrals slightly punctate. 

213. Astyanax mutator Eigenmann. (Plate LI, fig. 3.) 

"Punkay." 
Astyanax mutator Eigenmann, Ann. Carnegie Mus., VI, 1909, 18; Repts. Princeton 

Univ. Exp. Patagonia, III, 1910, 434. 

Type, 53 mm. Savannah Landing, Upper Potaro. (Carnegie Museum Cat- 
alog of Fishes No. 1023.) 

Cotypes, one hundred and twenty specimens, 23-58 mm. Savannah Landing, 
Upper Potaro. (C. M. Cat. No. 1024a-2; I. U. Cat. No. 11724.) 

Head 4; depth 2.75-3; D. 11; A. 21-24, most frequently 22; scales 6-33 to 
35-4.5; eye 2.75-3; interorbital equal to eye. 

Compressed; dorsal and ventral profiles equally curved; snout narrow, pointed; 
profile not depressed over the eye; preventral area rounded, without a distinct 
median series of scales; postventral area narrowly rounded; predorsal area keeled, 
with a median series of nine or ten scales. 

Occipital process very narrow, about one-fifth as long as the distance of its 
base from the dorsal, bordered on each side by three scales; interorbital convex; 
frontal fontanel much shorter than the parietal; second suborbital narrow, leaving 
a naked area, which is more than half as wide as the bone itself; maxillary equal to 
snout in length, its front margin very convex; width of lower jaw about half the 
orbit ; premaxillary with two to four teeth in the front series, five five-pointed teeth in 
the second series; maxillary with throe teeth, of which one is minute; dentary with 
five or six five-pointed teeth, graduate; abruptly a series of minute conical teeth 
on the sides. 

Gill-rakers 11 + 18. 

Scales regularly imbricate, no interpolated or omitted series; anal sheath of a 
single series of scales along anterior part of anal; lateral line little decurved, some- 
times broken or interrupted on the tail, each scale with several radiating striae. 

Origin of dorsal midway between tip of snout and base of middle caudal rays; 
highest dorsal ray nearly 4 in the length; origin of anal and ninth to eleventh dorsal 
rays equidistant from snout; anal very slightly emarginate; ventrals considerably 



354 MEMOIRS OF THE CARNEGIE MUSEUM 

in front of the vertical from the first dorsal ray, just reaching anal; pectorals just 
to ventrals or a trifle shorter. 

Dusky; a definitely circumscribed oval caudal spot, not continued forward or 
backward on the middle caudal rays; a well-defined bar crossing the second and 
third scales of the lateral line; sides of head and body everywhere profusely dotted; 
dorsal, caudal, and anal dotted; base of caudal with the outlines of the rays and 
their cross-breaks outlined in black, making this part of the fin darker. 

214. Astyanax mucronatus Eigenmann. (Plate LI, fig. 4.) 
Astyanax mucronatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 19; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 433. 

Type, 53 mm. Tumatumari, above the falls. (Carnegie Museum Catalog of 
Fishes No. 1025.) 

Cotypes, three specimens, 51-54 mm. Tumatumari, above the falls. (C. M. 
Cat. No. 1026; I. U. Cat, No. 11725.) 

Cotypes, fourteen specimens, 46-73 mm. Sand-bank in Potaro at Tukeit, 
(C. M. Cat. No. 1027a-e; I. U. Cat. No. 11726.) 

Head 3-6; depth 2.3-2.6; D. 11; A. 25-26, rarely 27; scales 6-34 or 35-5 
(rarely 4) . Eye 2.7 in the head, 2 in the head without the opercle ; interorbital 3-3.5 
in the head. 

Compressed, subrhomboidal, with heavy head and slender caudal peduncle. 
Dorsal profile slightly depressed over the eye, rising with a gentle curve to the 
origin of the dorsal, abruptly descending to the end of the dorsal and then with a 
more gentle slope to the caudal peduncle. Ventral profile more regularly arched. 
Preventral region broadly rounded; postventral area more narrowly rounded; 
predorsal area keeled, with a median series of eight scales. 

Occipital crest exceptionally narrow at the base; about one-fourth of the 
distance from its base to the dorsal, bordered by three scales on the sides; skull 
narrow, slightly convex, smooth. Fontanels very narrow and long, the frontal 
fontanel as long as the parietal. Second suborbital leaving but a very narrow naked 
area. Maxillary but little longer than snout, 3.3 in the head. Premaxillary with 
two or three teeth in the front series, five teeth in the second series, their denticles 
in a straight line; two teeth on the maxillary; lower jaw with eight teeth arranged 
in a crescent (four on each side), and smaller teeth on the sides. 

Gill-rakers 5 + 10. 

Scales very regularly imbricate, without interpolated or omitted rows. Each 
scale with several slightly diverging striae; anal sheath of a single row of scales 
along the base of the anterior rays; caudal naked. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 355 

Origin of dorsal nearer to snout than to caudal, 3.4 in the length; anal emargi- 
nate, its origin about equidistant from snout with the eighth dorsal ray; ventrals 
reaching anal, their origin a little in advance of that of the dorsal. Pectorals 
reaching beyond origin of ventrals. 

A conspicuous parabolic humeral spot, the blunt end forward, and a faint 
dark streak extending below it; a diffuse caudal spot occupying the entire width 
of the end of the caudal peduncle. 

Dorsal line dark; sides profusely covered with pigment cells, disappearing on 
the belly; cheeks and opercles dotted; fins dotted; upper and lower margin of caudal 
dark. Straw-colored in life; bases of dorsal, anal, and caudal lobes ochreous. 

215. Astyanax wappi (Cuvier and Valenciennes). (Plate LII, fig. 1.) 
Tetragonopterus wappi Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 

1848, 153 (Guiana).— Gunther, Catalogue, V, 1864, 326 (British Guiana) .- 

Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 53. — Ulrey, 

Ann. N. Y. Acad. Sci., VIII, 1895, 278. 
Astyanax wappi Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

433. 

I have examined the type, No. 2336, Jardin des Plantes, 105 mm. in total 
length. Head 3.33; depth 3; scales 6-36-5 (type), 7-38-6; eye 1.5 in the very 
convex interorbital, 1 in snout, 4 in head; A. 27; maxillary with one tooth; predorsal 
line scaled. Dorsal and anal profile about equally arched; second preorbital 
striate; a large oval humeral spot, twice as long as high; a dark caudal spot ex- 
tending forward on the sides; traces of longitudinal streaks between the rows of 
scales. The figure is based on a specimen in the British Museum. 

It is quite possible that both specimens said to have come from Guiana (the 
one in Paris and the one in London) actually came from the Branco basin, and 
should therefore be excluded from this account. 

Poscilurichthys Gill. 
Poecilurichthys Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 414. 
Like Astyanax, except that the predorsal line is naked. 
Type, Poecilurichthys brevoortii Gill. 

a. Scales 42-50. 

6. Lateral line 42-40; a round .spot over the seventh to ninth scale of the lateral line; no caudal spot. 

polylepis. 
bb. Lateral line 43-51; a narrow ovate spot over the first five scales of the lateral line; a large caudal spot. 

abramoides. 



356 MEMOIRS OF THE CARNEGIE MUSEUM 

aa. Scales 41, usually fewer. 

d. Anal margin straight; a black stripe on the caudal peduncle, continued on the middle rays. 

bimaculatus. 
del. Anal emarginate, a black band across the base of the caudal potaroensis. 

216. Poecilurichthys polylepis (Gunther). (Plate LII, figs. 2, 3.) 
Tetragonopterus maculatus Muller and Troschel, Horse Ichth., I, 1845, 74, part; 

in Schomburgk, Reisen, III, 1848, 634, part. 
Tetragonopterus polylepis Gunther, Catalogue, V, 1864, 320 (British Guiana). 
— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 52.— 

Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 276. 
Poecilurichthys polylepis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 433. 

One specimen, 44 mm. Wismar. (C. M. Cat. No. 1416a.) 

Nineteen specimens, 35-53 mm. Rockstone. (C. M. Cat. No. 1418a-d; 
I. U. Cat. No. 11789.) 

Ten specimens, 38-52 mm. Gluck Island. (C. M. Cat, No. 1417a-c; I. U. 
Cat. No. 11790.) 

Ten specimens, 49-85 mm. Crab Falls. (C. M. Cat. No. 1415o-c; I. U. 
Cat. No. 11791.) 

Sixty-nine specimens, 50-85 mm. Tumatumari. (C. M. Cat. No. 1419a-j; 
I. U. Cat. No. 11792.) 

Readily distinguished by its circular spot over the seventh to ninth scales of 
the lateral line, and by its small scales. 

Head 3.5-4; depth 2 in the largest to 2.5 in the young; D. 11; A. 27-31 47 ; 
scales 10-42 to 46 4S -7 to 9 to ventrals; eye 3; interorbital 2.3. 

Much compressed, very deep in the old, the ventral profile pendant; dorsal 
profile regularly arched from the snout to the caudal peduncle; much slenderer 
in the young, but maintaining the same ratio of curvature between back and belly. 
Preventral region narrowly rounded, the pectorals considerably above the lower 
edge of the breast; scales of belly irregularly imbricate; postventral area narrowly 
compressed; entire back very narrow, not especially keeled. Predorsal area naked 
to near the dorsal, where there are a few median scales or a few of the scales of one 
side overlapping the back. 

Occipital process one-fourth of the distance from its base to the dorsal, bor- 
dered on the sides by five scales; skull smooth, very convex; frontal fontanel shorter 

47 Gunther gives the anal as 3-1 in 1 he type. In twenty specimens examined two have 27 rays, four have 
28, eight have 29, four have 30 and two have 31. 

48 In sixteen six have 42, six have 43, two have 44, one has 45 and one 46. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 357 

than the parietal, extending to above the anterior margin of the pupil; margin of 
second suborbital very convex, leaving but a narrow naked margin; maxillary 2.66 
in the head, the mouth large. Four to six teeth in the front row of the premaxillary, 
the third withdrawn from the line of the rest; five teeth in the second series, their 
denticles in a straight line; eight large teeth in the lower jaw (four on each side) 
arranged in a crescent; small teeth on the side. 

Scales of the sides and back regularly imbricated; a few interpolated scales over 
the anal muscles; a row of about twelve scales forming a sheath along the base of 
the anterior rays. Scales of belly and breast not very regularly arranged; lateral 
line but little decurved; axillary scale well-developed. 

Dorsal equidistant with the ventrals from the snout, its origin a little in ad- 
vance of the middle, its highest ray 3.5 in the length; anal emarginate; ventrals 
not reaching anal; pectorals slightly beyond origin of ventrals. 

Highly iridescent; a round spot over the seventh to the ninth scale of the 
lateral line, with a dark streak extending down from it and another curving upward 
and forward, surrounded by a lighter area; sides and fins thickly punctate, especially 
in a lateral band on a level with the humeral spot. Tip of first anal ray sometimes 
milk-white. 

217. Poecilurichthys abramoides (Eigenmann). (Plate LII, fig. 4.) 

Tctragonoptcrus abramis (not of Jenyns) Gunther, Catalogue, V, 1864, 321 (British 
Guiana; Essequibo). — Steindachner, "Flussfische Sudamerika's, " i, 1879, 8 
(Orinoco near Ciudad Bolivar). 

Astyanax abraynoides Eigenmann, Ann. Carnegie Mus., VI, 1909, 21; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 432. 
Type, 112 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 

1028.) 

Cotypes, eighty-six specimens, 48-112 mm. Tumatumari. (C. M. Cat. No. 

1029r ( -j; I. U. Cat, No. 11727.) 

Cotypes, two specimens, 99-126 mm. Potaro Landing. (C. M. Cat, No. 

1030; I. U. Cat. No. 11728.) 

Cotypes, twenty-seven specimens, 60-126 mm. Kangaruma. (C. M. Cat. 

No. 1031a-e; I. U. Cat, No. 11729.) 

Cotypes, forty-eight specimens, 56-108 mm. Amatuk Cataract, (C. M. 

Cat. No. 1032a-,/; I. U. Cat. No. 11730.) 

Cotype, one specimen, 54 mm. Rockstone. (C. M. Cat. No. 1033.) 
Cotype, one specimen, 46 mm. Gluck Island. (C. M. Cat, No. 1034.) 



358 MEMOIRS OF THE CARNEGIE MUSEUM 

Cotypes, two specimens, 56-63 mm. Wismar. (C. M. Cat. No. 1035; I. U. 
Cat. No. 11731.) 

Cotypes, two specimens, 51-64 mm. Christianburg. (C. M. Cat. No. 1036; 
I. U. Cat. No. 11732.) 

( 'losely allied to P. anterior and P. abramis, but differing from both in the color 
of the caudal peduncle and caudal. 

Head 4; depth 2.4-2.5; D. 11; A. usually 28; 49 scales 9 or 10-43 to 51 50 -7 or 8; 
eye 2.5-3; interorbital 2.5-2.6. 

Elliptical; dorsal and ventral outlines similar, without prominent humps, the 
profile slightly depressed over the eyes. Preventral area rounded, with small, 
rather irregularly placed scales; postventral area narrowly rounded; predorsal 
area narrow, with a linear median naked area. 

Occipital process equal to one-fourth of the distance from its base to the dorsal, 
bordered by four scales on its sides; skull smooth in cross-section, very convex; 
interorbital much broader than the eye in adult; frontal fontanel a little narrower 
than the parietal; margin of second suborbital very convex, leaving a naked area, 
which is widest below; maxillary equal to the eye; four or five teeth in the front 
row of the premaxillary, the third withdrawn from the line of the rest; five gradu- 
ated teeth in the second row, their denticles in shallow crescents: maxillary with 
two or three minute teeth; dentary with four large teeth, abruptly followed by smaller 
ones on the sides. 

Gill-rakers 8+11. 

Scales of the sides regularly imbricated; a few interpolated scales over the anal 
muscles; anal sheath of a single row of scales along the base of the anterior rays; 
caudal naked; a well-developed axillary scale; lateral line but little decurved. Each 
scale of the sides with a few nearly parallel stria?. 

Dorsal but little farther from snout than the ventral, nearer to snout than to 
caudal, its margin rounded, the highest ray about 3.75 in the length, the penulti- 
mate a little less than half as long as the highest. Anal emarginate, the second and 
tenth reaching the base of the eighteenth when depressed; first anal ray below or 
behind the base of the last dorsal ray. Ventrals not reaching anal, pectorals to 
ventrals. 

Highly iridescent, blue above, greenish to silvery below; a club-shaped hori- 
zontal humeral spot, its pointed anterior end from the upper margin of the first 
scale of the lateral line along the row of scales above the latter to above the 

49 In those examined, one with 26, ten with 28, five with 29, three with 30. 

50 In those examined, one with 43, four with 44, two with 45, four with 46, four with 47, one with 51. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 359 

fifth scale of the line; a dark vertical bar crossing the opercle, followed by a light 
bar, a second dark bar across the posterior part of the humeral spot, a second 
light bar and then a third dark bar, shading into the profusely dotted sides. 
Cheeks profusely dotted; a dark median line, most prominent in young speci- 
mens preserved in formalin, this line not extending along the sides of the caudal 
peduncle; a black spot at the base of the caudal, its margins shading into the dusky 
caudal, but not definitely continued to the end of the middle rays. These markings 
fade with age. In life all fins but the pectorals are tinged with orange or brick-red. 

218. Poecilurichthys bimaculatus (Linnaeus). 

"Charax" No. 54, Gronow, Mus. Ichth., I, 1754, 19, pi. 1, fig. 5. 

Albula maculata Linnaeus, Mus. Adolphi Fred., 1754, 78, pi. 32, fig. 2. 

Tetragonopterus maculatus Muller and Troschel, Horse Ichth., I, 1845, 14, part, 
pi. 3, fig. 4; in Schomburgk, Reisen, III, 1848, 634, part (Rupununi; Essequibo). 
— Gunther, Catalogue, V, 1864, 321 (Demerara; River Capin; Pernambuco). 
— Steindachner, " Susswasserfische d. Stidostlichen Brasilien," iii, 1876, 568, 
pi. 1, fig. 2 (Rio Parahyba; Rio Doce; Rio Mucuri). — Peters, MB. Akad. 
Wiss. Berlin, 1877, 472 (Calabozo). — Boulenger, Ann. and Mag. Nat. Hist., 
XIX, 1887, 173 (Rio Grande do Sul). — Eigenmann and Eigenmann, Proc. 
U. S. Nat, Mus., XIV, 1891, 52.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 
275. — Perugia, Ann. Mus. Genova, (2a), X, 1891, 43 (Rio Paraguay; Asun- 
cion; Villa Maria). — Boulenger, Boll. Mus. Zool. ed. Anat. Comp. Torino, X, 
1895,3 (Colonia Risso).— Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 157 
(Apure). — Regan, Proc. Zool. Soc. London, 1906, 384 (Trinidad). 

Salmo bimaculatus Linnaeus, Syst. Nat,, ed. 10, 175S, 311, No. 20; ed. 12, 1766, 513 
(South America). — Bloch, Ausl. Fische, 1794, pi. 382, fig. 2. — Bloch and 
Schneider, Syst, Ichth., 1801, 413. 

( 'harax bimaculatus Gronow, Cat. Fish, ed. Gray, 1854, 154. 

Astyanax bimaculatus Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 432 (headwaters 
of the Tocantins). — Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIIL 
1907, 27, part (Para; British Guiana). — Eigenmann, Repts. Princeton Univ. 
Exp. Patagonia, III, 1910, 432. 

Tetragonopterus linncei Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

142 (Cayenne). 

Tetragonopterus gronovii Cuvier and Valenciennes, Hist. Nat, Poiss., XXII. 1848, 

143 (Surinam). — Kner, "Familie der Characinen," i, 1859, 39. — Kner and 
Steindachner, Abhand. K. Bayer. Akad. Wiss., II Kh, X, 1864, 46 (Rio 
Bayano). 



360 MEMOIRS OF THE CARNEGIE MUSEUM 

Tetragonopterus orbignianics Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 

1849, 147 (Buenos Aires). 
Poecilurichthys brevoortii Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 417 (Trinidad). 

— Gunther, Catalogue, V, 1864, 317. 
Tetragono'pterus brevoortii Lutken, Vidensk. Med. Nat. For. Kjobenhavn, 1874, 

232.— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 53 — 

Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 275. 
Tetragono'pterus bartletti Gunther, Ann. and Mag. Nat. Hist., (3), XVIII, 1866, 

30 (upper Amazon).— Cope, Proc. Acad. Nat, Sci. Phila., 1871, 260 (Am- 

byiacu) . 
Astyanax bartlettii Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 343, fig. 31 (Am- 

byiacu). 
Tetragonopterus orientalis Cope, Proc. Am. Philos. Soc, XI, 1870, 559 (Para). — 

Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 279. — Ulrey, 

Ann. N. Y. Acad. Sci., VIII, 1895, 279. 
Astyanax orientalis Fowler, Proc. Acad. Nat. Sci: Phila., 1906, 434, fig. 35. 
Astyanax microstoma Hensel (not of Gunther), Archiv fur Naturg., 1870, 83. 
Tetragonopterus lacustris (not of Lutken) Boulenger, Trans. Zool. Soc. London, 

XIV, 1896, 35 (Descalvados and North Paraguay). — Eigenmann and Norris, 

Rev. Mus. Paulista, IV, 1900, 357 (Piracicaba). 
Astyanax lacustris Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 433 (Para, Peruvian 

Amazon). 
Tetragonopterus maculatus lacustris Eigenmann, Ann. N. Y. Acad. Sci., VII, 1894, 

633 (Rio Grande do Sul).— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 275. 
—Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 521 (Asun- 
cion; Estancia la Armonia; Arroyo Trementina). — Eigenmann and Ward, 

MS. (Corumba; Bahia Negra; Porto Max; Sapucay). 
Tetragonopterus caudimaculatus Cope, Proc. Am. Philos. Soc, XXXIII, 1894, 107 

(headwaters of Tocantins). 
? Tetragonopterus jacuhiensis Cope, Proc. Am. Philos. Soc, XXXIII, 1894, 88 

(Rio Grande do Sul).— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 280.- 

Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 435 (Jacuhy). 

One specimen, 102 mm. 51 Maripicru, branch of the Ireng. (C. M. Cat. No. 
1354a.) 

Five specimens, 87-133 mm. Holmia. (C. M. Cat, No. 1355a-6; I. U. Cat. 
No. 11847.) 

51 This specimen has but twenty-seven anal rays, and scales 7-37-6. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 361 

One hundred and two specimens, 37-142 mm. Georgetown trenches. (C. M. 
Cat. No. 1356o-z; I. U. Cat. No. 11848.) 

One hundred and twenty-two specimens, 51-126 mm. Botanic Garden. (C. 
M. Cat. No. 1357a-z; I. U. Cat. No. 11849.) 

Seven specimens, 74-85 mm. Lama Stop-Off. (C. M. Cat, No. 1358a-o; I. 
U. Cat, No. 11850.) 

One specimen, 79 mm. Maduni Creek. (C. M. Cat, No. 1359a.) 

Two specimens, 83-84 mm. Mora Passage. (C. M. Cat, No. 1360a; I. U. 
Cat, No. 11851.) 

Head 3.5-4.3; depth 2-2.6; D. 11; A. 28-36, most frequently 32; scales 7-37 
to 41-6; eye about 3 in the head; interorbital 2.3-2.4. 

Elliptical; predorsal area narrowly rounded, with a few median scales near 
the dorsal. Occipital process one-third to one-fourth in the distance between its 
base and the dorsal; second suborbital leaving a narrow naked area. 

Anal slightly emarginate in the young, straight in the adult. 

A well-defined, horizontally ovate, black humeral spot over the third to the 
sixth, or second to the fifth scale of the lateral line; a spot on the caudal peduncle, 
fading out forward and continued behind to the tip of the middle caudal rays. 

219. Pcecilurichthys potaroensis (Eigenmann). (Plate LII, fig. 5.) 
Astyanax -potaroensis Eigenmann, Ann. Carnegie Mus., VI, 1909, 22; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 433. 

Type, 58 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1037.) 
Cotypes, twelve specimens, 51-64 mm. Amatuk. (C. M. Cat. No. 1038a-c; 
I. U. Cat. No. 11733.) 

Cotype, one specimen, about 59 mm. Kangaruma. (C. M. Cat. No. 1039.) 
Cotype, one specimen, 45 mm. Tukeit. (C. M. Cat. No. 1040.) 
Cotypes, two specimens, 47-49 mm. Erukin. (C. M. Cat, No. 1041; I. U. 
(Vat, No. 11734.) 

Evidently allied to P. bimacidatns and P. orthodus. It is readily distinguished 
from the former by the emarginate anal, the broad caudal band, and the absence 
of any stripe on the caudal peduncle. In the coloration of the sides it approaches 
P. abramoides, the humeral spot being less defined, the black lateral line being 
absent. Its anal is distinctly shorter than that of orthodus. 

Head 3.5; depth 2.6-3; D. 11; A. 27 or 28, rarely 29; scales 8 (rarely 9)-37 to 
38 62 -6 or 7; eye 2.75; interorbital 3. 

52 Tn ten individuals five have 37, three have 38, one has 39, and one 41 scales. 



362 MEMOIRS OF THE CARNEGIE MUSEUM 

Elongate, subrhomboidal, profile rising rapidly in front, then curved more 
gently to the dorsal; ventral profile regularly rounded. Preventral area convex, 
without a distinct median series of scales; post ventral area narrowly rounded; 
predorsal area narrowly rounded, two scales in front of the dorsal, the median line 
otherwise naked to the occipital process. 

Occipital process very narrow, its width not quite half its length, which is 
about one-fifth as long as the distance from its base to the dorsal, bordered by three 
scales on the sides. Interorbital smooth and convex; frontal fontanel a little 
narrower and a little shorter than the parietal; second suborbital leaving a con- 
siderable naked area, which is widest below; mouth large, maxillary a little longer 
than the eye; normally four teeth in the outer series of the premaxillary, of which 
the third is withdrawn from the line of the rest; five teeth in the second series; maxil- 
lary with three small teeth; mandible with four large teeth in the dentary and 
abruptly minute ones on the side. 

Gill-rakers 6 + 14, those of the upper arch excessively minute, those of the 
lower arch about one-third the length of the eye. 

Scales of the sides regularly imbricate, no interpolated scales over the anal; 
scales of the ventral surface less regularly imbricate ; lateral line but little decurved ; 
anal sheath composed of a single series of scales along the base of the anterior rays. 

Ventrals but little nearer the snout than to the dorsal, which is a little nearer 
to the snout than to the caudal; highest dorsal ray about 4 in the length. Anal 
emarginate. the second and fourteenth rays reaching the base of the twentieth ray. 
Ventrals not reaching anal, pectorals just to ventrals. 

Coloration much as in abramoides. A dark bar crossing opercle, a second bar 
some distance behind this in a light area, the second bar widest above the lateral 
line, where it forms an indistinct humeral spot; a third bar shading into the thickly 
dotted sides; cheeks thickly punctate; a dark dorsal streak. A black band crossing 
the base of the caudal and sometimes extending out along the outer rays. No 
dark line along the sides in formalin specimens, but sometimes dark streaks up and 
down from the median line between the muscle segments. 

Ctenobrycon Eigenmann. 

Ctenobrycon Eigenmann, Bull. Mus. Comp. Zool., XLI, 1908, 94. 

Type, Tetragonopterus hauxwellianus Cope. 

Distinguished from all other Tetragonopterids by its ctenoid scales. 

Anal long, its margin nearly straight, its origin behind or below the origin of 
the dorsal; mouth very small, the maxillary not reaching the eye; scales of the 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 363 

breast ctenoid, those of the sides cycloid in young, becoming ctenoid in adult; 
lateral line always complete, a long tube extending on the middle caudal membrane; 
caudal naked; maxillary with none or two teeth; a series of tricuspid teeth in the 
premaxillary and an inner series of five-pointed ones, the denticles of which are 
arranged in a U-shaped curve; predorsal area scaled. 

Premaxillary teeth in parallel series, the third tooth of the first series not being 
out of line with the rest. 

One species is found in the Guianas. 

220. Ctenobrycon spilurus (Cuvier and Valenciennes). (Plate XLVII, fig. 1.) 
Tetragonopterus spilurus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 
156 (Surinam). — Gunther, Catalogue, V, 1864, 318. — Eigenmann and Eigen- 
mann, Proc. U. S. Nat. Mus., XIV, 1891, 52.— Ulrey, Ann. N. Y. Acad. Sci., 
VIII, 1895, 274. 
Ctenobrycon spilurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 435. 

Several hundred specimens, the largest 77 mm., from the trenches of George- 
town and the Botanic Garden. (C. M. Cat, No. 1425 and 1426.) 

Head 4.25-4.5; depth 2.25-3; D. 11; A. usually 41-45 53 ; scales 11 or 12-41 to 
50-7 to 10; eye 2.75-3. 

Deuterodon Eigenmann. 
Deuterodon Eigenmann, Ann. Carnegie Mus., IV, 1907, 140, pi. 41, fig. 3 (iguape). 
Joinvillia Steindachner, Wien Anz. Akad.-Wiss., XIV, 1908, 30 (rosce). 
Type Deuterodon iguape Eigenmann. 

Compressed, elliptical fishes of small size, 54 most nearly related to Astyanax, 
from which they differ in dentition. Teeth all multicuspid incisors, those in the 
premaxillary in two series, those in the maxillary (2-7) and in the mandible in a 
single series, the latter graduate; lateral line complete; caudal naked. Lives 
largely in cataracts. 

Key to the Guiana Species of Deuterodon. 

a. Each pore of the lateral line surrounded by black potaroensis. 

aa. A black median band or line, usually with pinnately diverging lines pinnatus. 

221. Deuterodon potaroensis Eigenmann. (Plate LIII, fig. 1.) 
Deuterodon potaroensis Eigenmann, Ann. Carnegie Mus., VI, 1909, 27; Piepts. 
Princeton Univ. Exp. Patagonia, III, 1910, 431. 

63 Of those examined one has 36, one has 39, one has 40, three have 41, seven have 42, four have 43, 
four have 44, three have 45, one has 46, and one has 47 anal rays. 
54 The greatest recorded length is about 13 cm. over all. 



364 



MEMOIRS OF THE CARNEGIE MUSEUM 



Type, 43 mm. Amatuk. (Carnegie Museum Catalog of Fishes No. 1053). 

Cotypes, five specimens, 39-50 mm. Amatuk. (C. M. Cat. No. 1054; 
I. U. Cat, No. 11744.) 

Cotypes, three specimens, 31-35 mm. Waratuk. (C. M. Cat. No. 1055; 
I. U. Cat. No. 11745.) 

Two specimens, 35-43 mm. Erukin. (C. M. Cat. No. 2455a-6.) 

This species was taken by using poison in a little side branch of the Waratuk 
Cataract, and in the same way in a larger branch of the Amatuk Cataract. 

Head 3.8-4; depth 3.2-3.5; D. 9 or 10; A. 24 or 25 (rarely 27); scales 6-37 to 
40-4. Eye 2.5; interorbital equal to eye. 

Elongate, little compressed, heavy at shoulder; dorsal and ventral profiles 
equally arched, without hump or depressions; preventral area narrowly rounded, 
with a median series of scales; postventral area compressed to a narrow edge; 
predorsal area keeled, with a median series of about thirteen scales. 

Occipital process about one-fifth of the distance from its base to the dorsal, 
bordered by three scales; head narrow, smooth above, slightly convex; frontal 
fontanel much shorter than the parietal, narrow; second suborbital leaving a naked 
area about one-third as wide as its own greatest width; maxillary longer than snout, 
but not quite equal to eye; premaxillary with three three-pointed teeth in the front 
row and five three- to five-pointed ones in the second; denticles of the second row 
in a more or less open crescent; four or five maxillary teeth similar to those of the 
inner row of the premaxillary. Mandible with seven graduated multicuspid 
incisors, followed by one or two conical incisors. 

Gill-rakers 6 + 12. 

Origin of dorsal a little nearer snout than to caudal, its penultimate ray a little 
more than half as long as the longest ray, which is about one-fourth of the length. 
Margin of anal straight, the rays graduate from the anterior longer ones; ventrals 
very short, not reaching anal, a little nearer to the snout than the dorsal; pectorals 
reaching ventrals. 

Markings in formalin specimens: each pore of the lateral line surrounded by 
black, the dots forming a conspicuous line; bases of two rows of scales below the 
lateral line over the abdomen and three or four rows of scales above the lateral line 
dark, the spots forming fainter longitudinal lines; margins of scales of the upper 
parts of the sides and the entire dorsal line very dark ; a faint comma-shaped vertical 
humeral spot interrupted in the middle; a dark lateral band intensified in spots and 
ending in a caudal spot, which extends from a little above the lateral line to the 
lower margin of the caudal; ventral fins dusky. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 365 

222. Deuterodon pinnatus Eigenmann. (Plate LIII, fig. 2.) 
Deuterodon pinnatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 26; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 431. 

Type, 62 mm. Amatnk. (Carnegie Museum Catalog of Fishes No. 1046.) 

Cotypes, twenty-five specimens, 32-75 mm. Amatuk. (C. M. Cat. No. 
1047a-e; I. U. Cat. No. 11738.) 

Cotypes, two specimens, 36-40 mm. Konawaruk. (C. M. Cat. No. 1048; 
I. U. Cat. No. 11739.) 

Cotypes, nineteen specimens, 21-43 mm. Warraputa. (C. M. Cat. No. 
1049a-c; I. U. Cat. No. 11740.) 

Distinguished from all other Tetragonopterids by the pinnate black markings 
of the sides. 

Head 4-4.3; depth 2.5-2.7; D. 10 or 11; A. 24-25, rarely 27; scales 6-36 or 
37-4 or 5. 

Compressed, subrhomboidal; profile slightly depressed over the eye; preventral 
area rounded; the scales large, a nearly regular median series; postventral area 
narrowly rounded, the anus directly in front of the anal; predorsal area narrowly 
rounded, with a median series of about nine scales. 

Occipital process triangular, not quite one-fourth of the distance from its base 
to the dorsal, bordered by three scales; interorbital convex; fontanels narrow, the 
anterior shorter than the parietal; second suborbital deep, leaving a wide naked 
area; maxillary about 3.5 in the head; three or four teeth in the outer row of the 
premaxillary ; five graduated teeth in the inner series, expanded at top, the denticles 
in a crescent, the middle one not notably larger or longer than the others; three 
or four similar teeth in the maxillary; dentary with eight to ten graduated teeth, 
similar to those of the premaxillary, but with longer median point; all the teeth 
brown-tipped. 

Gill-rakers short, 6+10. 

Ventrals in advance of the vertical from the dorsal; origin of dorsal in the 
middle or slightly in advance of the middle, its highest ray 3.75 in the length; 
twelfth anal ray two-fifths to about half as high as the highest, the anal margin 
concave or not; pectorals reaching slightly beyond origin of ventrals, ventrals 
not quite to anal. 

Cheeks and opercles punctate; a well-developed humeral spot in a vertical 
humeral band ; a second band in front of the dorsal, shading into the much punctate 
sides; a black median line, from which black streaks branch along the septa of the 
muscles at every other myotome; a conspicuous, large caudal spot, not continued 



366 MEMOIRS OF THE CARNEGIE MUSEUM 

to the end of the middle rays. Dorsal, adipose, caudal, and anal punctate, the 
latter sometimes most so along the base and tip. 

There are also in the collection: 

Cotypes, forty-one specimens, 21-68 mm. Amatuk. (C. M. Cat. No. 
1050a-j; I. U. Cat. No. 11741.) 

Cotypes, seven specimens, 20-69 mm. Waratuk. (C. M. Cat. No. 1051a-6; 
I. U. Cat, No. 11742.) 

Cotypes, three specimens, 23-40 mm. Savannah Landing. (C. M. Cat. 'No. 
1052; I. U. Cat. No. 11743.) 

These differ from the typical specimens described in that the color along 
the sides is in a dark band, instead of pinnately distributed, continued to the caudal 
spot, which is continued to the end of the middle caudal rays. A. 23-25. Lateral 
line 37, 37, 38, 38, 39, 40 in the six largest specimens from Amatuk. 

Phenacogaster Eigenmann. 
Phenacogaster Eigenmann, Am. Nat,, XLI, 1907, 769. 

Origin of anal under origin of dorsal; lateral line complete; scales in front of 
the ventrals in two series, overlapping in the middle. 

Type, Phenacogaster pectinatus (Cope). 

Range: Amazons and Guiana. 

Key to the Guiana Species of Phenacogaster. 
a. Lateral spot large, subcircular; a scale in the angle of each pair of the ventral series of scales, except the two 
pairs between the pectorals; scales with numerous radial strise; A. 33-37; scales 6-33 to 36-4 or 5; 
premaxillary with four to seven teeth in the outer series and five to seven three-lobed teeth and one to 

three conical teeth. A caudal spot, not continued to the end of the middle rays megalostictus. 

aa. Lateral spot minute, inconspicuous; few if any scales in the angles of the pairs of scales along the ventral 
surface; base and margin of anal dotted, the middle hyaline; scales with concentric striw; radial stria' 
inconspicuous or absent. A. 37-40; scales 6-38 or 39-5; premaxillary with four tricuspid and five 
conical teeth in the inner, series; no caudal spot microstictus. 

223. Phenacogaster megalostictus Eigenmann. (Plate LIII, fig. 3.) 
Phenacogaster megalostictus Eigenmann, Ann. Carnegie Mus., IV, 1909, 28; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 431. 

Type, 65 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 
1056.) 

Cotypes, fifty-nine specimens, 42-77 mm. Tumatumari, Lower Potaro River. 
(C. M. Cat. No. 1057a-.?'; I. U. Cat, No. 11746.) 

Cotype, one specimen, 55 mm. Tukeit, (C. M. Cat. No. 1058.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 367 

Cotypes, five specimens, 46-64 mm. Sand-hank at Tukeit. (C. M. Cat. 
No. 1059; I. U. Cat. No. 11747.) 

Cotypes, four specimens, 68-85 mm. Amatuk. (C. M. Cat. Xo. 1060; I. U. 
Cat. No. 11748.) 

Cotypes, sixteen specimens, 41-64 mm. Crab Falls. (C. M. Cat. No. 
1061a-e; I. U. Cat. No. 11749.) 

Cotypes, eighteen specimens, 36-64 mm. Rockstone. (C. M. Cat. No. 
1062a-e; I. U. Cat, No. 11750.) 

Head 3.8-4; depth about 2.66; D. 11; A. 33-37, usually 35 or 36;« scales 6-33 
to 36 56 -4 to 5; eye 2.33-2.66; interorbital 3.5-4. 

Elongate rhomboidal, heavy forward, the tail much compressed; profile com- 
pressed over the eye, arched in front of the dorsal; prevcntral area flat, with two 
series of large scales overlapping along the middle, a small scale in the angle of each 
pair of the overlapping scales, except the two pairs between the pectorals; midline 
of postventral area naked; preclorsal area bluntly keeled, with about ten median 
scales. 

Occipital process one-fourth or one-fifth of the distance from its base to the 
dorsal, bordered by four scales on the sides; interorbital flat, the upper margin of 
the eye on a level with the middle of interorbital ; frontal fontanel as long as the 
parietal, narrower than the latter, reaching to above the anterior margin of the 
pupil; second suborbital corrugate, leaving a wide naked margin; premaxillary- 
maxillary border without a distinct angle, moderately oblique; a maxillary of 
nearly equal width throughout, not slipping" under or over the first suborbital; 
snout blunt, the lower jaw included. 

Mandible with four to six narrow graduated teeth, with a large central and a 
minute lateral cusp on each side; sides of mandible with about ten minute teeth; 
premaxillary with four to seven teeth in a line parallel with the second row, which 
consists of about five to seven three-lobed and one to three conical teeth ; maxillary 
with eleven to sixteen conical or three-lobed teeth along about half the length of the 
maxillary. 

Gill-rakers 4 + 9. 

Scales everywhere regularly imbricate, without interpolate scales, each scale 
with several radiating strise; lateral line slightly decurved; anal sheath of a single 
series of graduate scales along the base of the first rays; caudal naked; axillary 
scale small. 

55 Of those examined three with 33, four with 34, six with '.in, seven with 36 and two with 37. 

56 Of those examined two with 33, three with 34, eight with 35, ten with 36. 



368 MEMOIRS OF THE CARNEGIE MUSEUM 

Origin of the dorsal a little in advance of the middle, pointed, the rays very 
rapidly decreasing from the highest, which is equal to about a third of the length. 

Anal emarginate, its origin and the third dorsal ray about equidistant from the 
snout; ventrals extending slightly beyond origin of anal; pectorals beyond base of 
ventrals. 

Straw-colored, with a silvery lateral band, slightly iridescent. A large, 
conspicuous, subcircular spot over the sixth to eighth scale of the lateral line, 
occupying the width of two scales (this spot frequently with a lunate encroach- 
ment in front) ; upper part of opercle and area below eye spotted, sometimes the 
rest of the cheek also spotted; a black median line more or less evident; a large 
caudal spot extending to near the middle (sometimes farther) of the median caudal 
rays; scales of the back always broadly margined with black, those of the flanks 
less so; above the anal the markings of the margin of the scales mixed with the lines 
of chromatophores following the muscle segments; tips of caudal nigrescent; anal 
nearly uniformly dotted, or the base and tip dotted, the rest hyaline; first anal rays 
milk-white. 

224. Phenacogaster microstictus Eigenmann. (Plate LIII, fig. 4.) 

Phenacogaster microstictus Eigenmann, Ann. Carnegie Mus., VI, 1909, 30; Repts. 

Princeton Univ. Exp. Patagonia, III, 1910, 431. 

Type, 48 mm. Tumatumari, Lower Potaro. (Carnegie Museum Catalog 
of Fishes No. 1063.) 

Cotypes, seven specimens, 28 mm. Konawaruk. (C. M. Cat. No. 1064a-c; 
I. U. Cat. No. 11751.) 

Cotype, one specimen, 29 mm. Rockstone. (C. M. Cat. No. 1065.) 

Cotypes, four specimens, about 35 to about 46 mm. Crab Falls. (C. M. 
Cat. No. 1066; I. U. Cat, No. 11752.) 

Head 4; depth 2.8; D. 11 ; A. 37-40, generally 39; scales 6-38 or 39-5; eye 2.5; 
interorbital 3.5. 

Only one or two small scales in the angles of the overlapping scales of the 
ventral surface; interorbital slightly convex. Maxillary teeth about seventeen, 
scattered along most of its length; premaxillary with four tricuspid and five conical 
teeth in the inner series; two or three teeth similar to the larger ones, and possibly 
sometimes a few conical teeth in the outer series; mandible with seven larger and 
a number of minute teeth. 

Scales with concentric strise, but with very few, or inconspicuous, radial stria 3 . 

Straw-colored; a very faint and small humeral spot over the seventh scale 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 3G9 

of the lateral line; a dark deep-lying line; two small deep-lying black spots at the 
bases of the caudal lobes; no caudal spot; caudal, except the middle of the base of 
the lobes, dusky; base and margin of anal dotted, the middle hyaline; sides of head 
and body profusely dotted, the dots on the flanks and back margining the scales, 
the margin consisting of a single row of chromatophores on the flank, of several 
rows on the back; dots over the anal muscles following the intermuscular septa. 
Cotypes all very much lighter. 

In one of the Crab Fall specimens the humeral spot is conspicuous, owing 
to the expansion of the chromatophores. 

Holobrycon Eigenmann. 

Holobrycon Eigenmann, Ann. Carnegie Mus., VI, 1909, 33. 

Type, Brycon pesu Mtiller and Troschel. 

Lower jaw with two series of teeth, those of the outer series lobed, those of 
the inner series conical. Inner series consisting of a pair of conical teeth near the 
symphysis and a series of much smaller teeth on the posterior part of the sides of 
lower jaw; upper jaw with three or more series of teeth. No fontanels in half- 
grown or adult specimens. 

225. Holobrycon pesu (Midler and Troschel). (Plate LIV, fig. 1.) 

" Pesu." 
Brycon pesu Muller and Troschel, Horse Ichth., 1, 1845, 30, pi. 7, fig. 1 ; in Schom- 

burgk, Reisen, III, 1848, 635 (Lower Essequibo and Mazaruni). — Gunther, 

Catalogue, V, 1864, 336. — Eigenmann and Eigenmann, Proc. U. S. Nat. 

Mus., XIV, 1891, 55. 
Holobrycon pesu Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

431. 

I have examined the type in Berlin and: 

One specimen, 80 mm. Warraputa Cataract. (C. M. Cat. No. 1809.) 

Two specimens, 102-116 mm. Crab Falls. (C. M. Cat. No. 1810; I. U. Cat. 
No. 12106.) 

One specimen, 84 mm. Gluck Island. (C. M. Cat. No. 1811.) 

Seven specimens, 78-100 mm. Rockstone. (C. M. Cat. No. 1812a-b; I. U. 
Cat, No. 12103.) 

Eighteen specimens, 29-109 mm. Bartica. (C. M. Cat. No. 1813a-d; 
I. U. Cat, No. 12104.) 

One specimen, 61 mm. Wismar. (C. M. Cat. No. 1814a.) 



370 MEMOIRS OF THE CARNEGIE MUSEUM 

Twenty-one specimens, 102-149 mm. Tumatumari. (C. M. Cat. No. 
1815a-e; I. U. Cat. No. 12105.) 

Head 4-4.2; depth 3.25-3.33; D. 11; A. 21-23; scales 8.5-41 to 44-3.5. Eye 
3.4-3.75 (3 in the smallest). 

Compressed, ventral profile more strongly arched than the dorsal; head 
pointed; area between ventrals narrowly rounded. 

Fontanels becoming closed when specimens reach a size of about 75 mm. 
Second suborbital covering the entire cheek in the adult; maxillary with teeth along 
its entire margin, slipping under, but not concealed by the preorbital; snout pro- 
jecting; premaxillary with eight to ten teeth in the outer row; four large teeth in 
the outer row of each side of the lower jaw, and smaller teeth on the sides. 

Origin of dorsal about equidistant from base of middle caudal rays and anterior 
margin of the eye; margin of dorsal rounded; adipose fin large; caudal forked, the 
lobes not twice as long as the middle rays, the middle rays not prolonged. 

Anal slightly emarginate; ventrals not reaching anal; pectorals barely reaching 
ventrals. 

Iridescent blue with faint dark cross-lines; a dusky humeral spot; adipose and 
margin of caudal dusky or black, the caudal sometimes watered. Dorsal, ventrals, 
middle of anal lobe, and a band on each caudal lobe, rusty. 

Subfamily Bryconin^e. 

Brycon M tiller and Troschel. 

Brycon Muller and Troschel, Horte Ichth., I, 1845, 15 (falcatus). 
Chalcinopsis Kner, SB. Akad. Wiss. Munchen, 1863, 226 (striatulus) . 
Megalobrycon Gunther, Proc. Zool. Soc. London, 1869, 423, fig. 1 (cephalus). 
Bryconodon Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1904, 146 

(orthotcenia) . 
Triurobrycon Eigenmann, Ann. Carnegie Mus., VI, 1909, 33 (lundii). 

Type, Brycon falcatus Muller and Troschel. 

With the characters of Holobnjcon, but the skull with two large fontanels. 

Two species of this genus have been recorded from British Guiana. They 
may be distinguished as follows: 

Key to the Guiana Species of Brycon. 
a. Middle caudal rays prolonged, forming a projecting point ; base of anal and a large V-shaped caudal spot 

black; dark lines along the rows of scales falcatus. 

an. Middle caudal rays prolonged, the caudal emarginate; fins largely black; dark lines between the rows of 
scales siebenthala. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 371 

226. Brycon falcatus Muller and Troschel. (Plate LIV, fig. 2.) 
? Chalceus labrosus Schomburgk, Fishes Brit. Guiana, I, 1841, 212 (Paduiri). 
Brycon falcatus Muller and Troschel, Horse Ichth., I, 1845, 29, pi. 6, fig. 1; 
in Schomburgk, Reisen, III, 1848, 635 (all rivers). — Gunther, Catalogue, V, 
1864, 334 (Essequibo; Surinam). — Eigenmann and Eigenmann, Proc. U. S. 
Nat. Mus., XIV, 1891, 55. — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 431. 
Brycon schomburgkii Muller and Troschel, Horee Ichth., I, 1845, 29, pi. 6, fig. 2 
(Essequibo); in Schomburgk, Reisen, III, 1848, 96 (Lower Essequibo).— 
Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 55. 
One specimen, 114 mm. Rockstone. (C. M. Cat, No. 1816.) 
Three specimens, 115-130 mm. Locality ? (C. M. Cat. No. 1817; I. U. Cat, 
No. 12109.) 

Twelve specimens, 223-275 mm. Tukeit. (C. M. Cat. No. 1818a-6; I. U. 
Cat, No. 12107.) 

Head 3.5-4; depth 2.6-2.8; D. 11; A. 26 or 27; scales 9-52-53-4; eye 3.4-3.75 
in head, 1.66-2 in interorbital, about equal to the length of the snout. 

Elongate oval, the dorsal and ventral outlines about equally convex; pre- 
ventral area broad, flattish; postventral area narrowly rounded; predorsal area 
narrowly rounded, without a definite median series of scales; head broad, the convex 
profile in front of the dorsal but little depressed over the eyes; second suborbital 
in contact with the angle of the preopercle, a narrow naked margin between it and 
the upper and lower limits of the preopercle. 

Upper jaw but slightly projecting, only the outer row of the premaxillary 
exposed; seven to ten teeth in the outer series in each premaxillary, six in the inner 
row and four between the two series; three large teeth on each side of the mandible, 
with graduated teeth on the sides. 

Origin of dorsal equidistant from tip of snout and base of middle caudal rays; 
dorsal obliquely truncate or slightly emarginate. Adipose fin well-developed. 
Caudal emarginate when opened, the middle rays forming a small projecting lobe; 
anal slightly emarginate in front; ventrals reaching beyond vent, but not to anal, 
pectorals not quite to ventrals. 

A humeral spot just behind the opercle above the lateral line. A conspicuous 
V-shaped black band on the caudal; base of anal black; sides highly iridescent, 
darker above; dark lines along the middle of the rows of scales above the lateral 
line; dorsal, adipose, and upper caudal margin rosy; an orange band parallel with 
the black band on caudal and anal in the smaller specimens in life. In the larger 
the dorsal, adipose, caudal and anal are dirty orange. 



372 MEMOIRS OF THE CARNEGIE MUSEUM 

I have examined the types of B. falcatus and B. schomburgkii in Berlin. The 
latter is undoubtedly the young of the former. It agrees with it in the markings 
of both the fins and in the lateral bands, which follow the middle of the rows of 
scales. 

227. Brycon siebenthalae sp. nov. (Plate LIV, fig. 3.) 

One specimen, 204 mm. Mud Creek, Aruka River. (C. M. Cat. No. 1819.) 

Head 4; depth 3; D. 11 ; A. 26; scales 12-64-7. Eye 1 in snout, 3.75 in head, 
2 in interorbital. 

Compressed; head short, blunt, broad; ventral profile regularly and more 
greatly arched than the dorsal; preventral area rounded, predorsal region bluntly 
keeled. 

Interorbital arched; second suborbital leaving a narrow naked margin; upper 
jaw scarcely projecting; twelve teeth in the outer series of the upper jaw; four 
large teeth in the outer row of the lower jaw. 

Origin of dorsal midway between tip of snout and base of middle caudal rays, 
the third ray longest, equal to head without opercle; caudal broad, emarginate, the 
lobes rounded, 4.5 in the length; pectorals not reaching ventrals. 

A faint humeral spot; series of dark lines between the rows of scales, most 
conspicuous over the anal. 

Pectorals and ventrals blue-black, the remaining fins dark. 

I take pleasure in naming this species for Miss Maud Siebenthal, who has pre- 
pared many of the illustrations for this volume. 

Chalceus Cuvier. 
Chalceus Cuvier, Mem. Mus. d'Hist. Nat., IV, 454. 

Type, Chalceus macrolepidotus Cuvier. 

With the dentition of Brecon, but an outer series of multicuspid and an inner 
series of conical teeth in the lower jaw; three series of teeth in the premaxillary. 
Scales of the back and down to the lateral line very large; lateral line much decurved, 
the scales below it much smaller than those above it. Gill-membranes free; belly 
rounded. 

A single species is known. 

228. Chalceus macrolepidotus Cuvier. 

Chalceus macrolepidotus Cuvier, Mem. Mus. d'Hist. Nat., IV, 454, pi. 21, fig. 1 — 
Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 240. — Schom- 
burgk, Fishes Brit. Guiana, I, 1841, 216, pi". 14 (Essequibo). — Gunther, 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 373 

Catalogue, V, 1864, 333 (Essequibo; River Cupai; British Guiana). — Cope, 
Proc. Acad. Nat, Sci. Phila., 1871, 262 (Ambyiacu).— Eigenmann and Eigen- 
mann, Proc. U. S. Nat. Mus., XIV, 1891, 55.— Eigenmann, Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 439. 
Brycon macrolepidotits Muller and Troschel, Horse Ichth., I, 1845, 15; in Schom- 

burgk, Reisen, III, 1848, 635 (Essequibo; Mazaruni). 
Chakeus ararapeera Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 
244 (Essequibo). 

Five specimens, 93-214 mm. Konawaruk. (C. M. Cat. No. 1961a-c; 
I. U. Cat. No. 12202.) 

Five specimens, 95-110 mm. Gluck Island. (C. M. Cat. No. 1962a-c; 
I. U. Cat. No. 12203.) 

Twenty-six specimens, 93-244 mm. Tumatumari. (C. M. Cat, No. 1963a-/; 
I. U. Cat. No. 12204.) 

Head 3.5-4; depth 3.6; D. 12; A. 11; scales 3.25-37 or 38-2, twenty to twenty- 
two scales in the series just above the lateral line. Eye 1.3 in snout, 3.6 in head, 2 
in interorbital; 1, 3, 1.3 respectively in the young. 

Elongate, ventral profile with a greater arch than the dorsal; ventral surface 
rounded, with a regular median series of scales; dorsal surface very broad, with a 
median series of seven scales before the dorsal; profile from the dorsal to the snout 
slightly curved, little descending; head broad, smooth, and flat above, the fontanels 
linear, becoming obliterated with age ; occipital process very short, scarcely evident 
externally. 

Cheeks with a narrow naked margin behind in the adult; the second suborbital 
in contact with the lower limb of the preopercle, but leaving a naked margin in the 
adult; premaxillaries meeting at an angle, with a considerable horizontal extent, 
meeting the straight-margined premaxillaries at an angle. Mouth terminal, the 
upper jaw projecting; the teeth much as in Brycon, lower jaw with two series of 
teeth; those of the outer series graduated, multicuspid, with ribbed convex outer sur- 
and concave inner surface, fourteen on each side; inner series consisting of minute 
face conical teeth, much more numerous than those of the outer series, the median pair 
much enlarged; each premaxillary with an outer series of about ten tricuspid 
slightly graduated teeth; an inner series of about six multicuspid teeth, of which 
the second is the largest, those following rapidly graduated; a middle series of 
two teeth, one outward from the space between the first and second of the inner 
series and one outward from the space between the second and third; maxillary 
with a series of teeth for nearly its entire length, those near its angle tricuspid, 



374 MEMOIRS OF THE CARNEGIE MUSEUM 

those farther out conical. Gill-membranes free from the isthmus and from each 
other; gill-rakers about 7 + 11. 

Scales of the back and sides large, with membranous border; each scale with 
a few large, and a multitude of minute, reticulating lines; a well-developed axillary 
scale; fins naked. 

Origin of dorsal equidistant from eye and caudal, its height about 5.5 in -the 
length; caudal broadly lobed, the lobes about 4 in the length; adipose fin small; 
anal short, emarginate, its lobe oblique, the longest ray usually extending beyond the 
tip of the last. Ventrals reaching about half-way to middle of anal, pectorals three- 
fourths to ventrals. 

Iridescent, plumbeous above; caudal and adipose deep maroon; dorsal rays 
similar, the membranes lighter; middle of ventral and pectorals maroon; lower 
parts yellowish-white, a maroon streak from above anal to above pectorals. 

Subfamily Stethaprionin^e. 
Fowlerina Eigenmann. 
Fowlerina Eigenmann, Am. Nat,, XVI, 1882, 772. 
Type, Tetragonopterus compressus Gunther. 

Predorsal spine scale-like, concave below, fitting into a notch in the back in 
front of the dorsal fin. Caudal scaled; anal long, with one row of scales. Scales 
34-36; preventral region with a median series of scales, none spinous. 

229. Fowlerina orbicularis (Cuvier and Valenciennes). (Plate XLVI, fig. 2.) 

Tetragonopterus orbicularis Cuvier and Valenciennes, Hist, Nat. Poiss., XXII, 
1848, 138 (Essequibo; Amazon). — Castelnau, Anim. Am. Sud, Poiss., 1855, 
65, pi. 32, fig. 3 (Amazon). — Kner, "Familie der Characinen," i, 1859, 38 
(Villa Maria).— Gunther, Catalogue, V, 1864, 320; Ann. and Mag. Nat. Hist., 
(5), VI, 1880, 12 (La Plata). — Eigenmann and Eigenmann, Proc. U. S. Nat. 
Mus., XIV, 1891, 52.— Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 276.— 
Vaillant, Bull. Mus. d'Hist. Nat., V, 1899, 155 (Carnot). 

Fowlerina orbicularis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 441. 

Tetragonopterus compressus Gunther, Catalogue, V, 1864, 319. (Essequibo; Suri- 
nam, Maranon). 

Brachychalcinus retrospina (in part) Boulenger, Ann. and Mag. Nat. Hist., (6), 
X, 1892, 12 (Santa Cruz). 

Fowlerina paraguayensis Eigenmann, Ann. Carnegie Mus., IV, 1907, 153. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 375 

Nineteen specimens, 41-81 mm. Crab Falls. (C. M. Cat. No. 1946a-e; 
I. U. Cat. No. 12207.) 

Three specimens, 44-50 mm. Lama Stop-Off. (C. M. Cat. No. 1947a; 
I. U. Cat. No. 12208.) 

One specimen, 50 mm. Amatuk. (C. M. Cat. No. 1948.) 

Two specimens, 58-87 mm. Creek below Potaro Landing. (C. M. Cat. No. 
1949; I. U. Cat. No. 12209.) 

Seventy-two specimens, the largest 71 mm., most of them about 50 mm. 
Konawaruk. (C. M. Cat. Nos. 1950a-?', and 2454 (figured) ; I. U. Cat, No. 12210.) 

Eighteen specimens, 96-115 mm. Kangaruma. (C. M. Cat. No. 1951a-e; 
I. U. Cat. No. 12211.) 

Twenty-four specimens, 40-83 mm. Rockstone. (C. M. Cat. No. 1952a-e; 
I. U. Cat, No. 12212.) 

Ninety-eight specimens, the largest 75 mm. Tumatumari. (C. M. Cat. No. 
1953a-{; I. U. Cat. No. 12213.) 

One hundred and sixty-four specimens, the largest 70 mm. Wismar. (C. M. 
Cat. No. 1954a-x; I. U. Cat. No. 12214.) 

Seven specimens, 45-52 mm. Warraputa. (C. M. Cat. No. 1955a-d; I. U. 
Cat. No. 12215.) 

Five specimens, 55-71 mm. Label lost, either Botanic Gardens or mud-flats 
below Wismar. (C. M. Cat. No. 1956a-c; I. U. Cat. No. 12216.) 

Eight specimens, 45-62 mm. Erukin. (C. M. Cat. No. 2206a-d; I. U. Cat. 
No. 12362.) 

Head about 4; depth nearly 2 in the young, 1.4 in some of the largest; D. 11 
or 12; A. 30-34, most frequently 32; scales 8-34 to 36-6 to 8. Eye .7 in the snout, 
2.4-2.6 in the head, 1+ in the interorbital. 

Extremely deep and compressed, preventral surface bluntly keeled; in part 
covered by median scales, in part by scales bent over the ridge; predorsal area 
keeled, with a median series of about eight scales; ventral arch more pronounced 
than the dorsal; anal base straight; predorsal profile arched, with a distinct de- 
pression over the eyes; occipital process, as in all deep species, very long and narrow, 
reaching one-third of the way to the dorsal, bordered by five scales on each side; 
predorsal spine in old individuals more or less leaf-shaped, with entire margins, 
in the young hastate, with a retrorse barb on each side; fontanel narrow, the parietal 
continued as a deep groove on the occipital process. 

Second suborbital leaving but a very narrow naked margin in the adult; jaws 
equal, the premaxillary with a short horizontal extent, meeting the maxillary at an 



376 MEMOIRS OF THE CARNEGIE MUSEUM 

angle; dentition as in Tetragonopterus, premaxillary with an inner series of about 
five teeth, whose denticles are in a crescent, and an outer series of four or more 
teeth, the second or third withdrawn from the line of the rest; dentary with four 
large teeth, abruptly followed by minute teeth on the side; maxillary slender, with 
as many as three teeth on its upper angle, these scarcely evident in small specimens. 

Gill-rakers long, slender, 10 + 16. 

Scales regularly imbricated, except over the anal musculature, each scale with a 
few radiating strife; lateral line but slightly decurved; anal with a sheath of two 
rows of scales, which are continuous with those of the sides; caudal lobes with 
minute scales for more than half their length. 

Dorsal pointed, the highest ray in the young reaching the adipose, shorter 
in the adult; adipose large; caudal forked, anal emarginate, more so in young than 
in adult; ventrals reaching to, or a little beyond, the origin of the anal, pectorals to 
above the middle of the ventrals. 

Highly iridescent, silvery; a silvery lateral band; two vertical humeral bars, 
the second merging into the pigmentation of the sides; outer margin of ventrals 
and anterior margin of anal frequently black; fins variously peppered. 

The specimens from Erukin differ from the rest as follows: the dorsal and anal 
are falcate, the longest dorsal rays reaching beyond the origin of the adipose, the 
longest anal ray to the base of the twenty-fifth ray. 

Subfamily ChalciniNjE. 

Chalcinus Cuvier and Valenciennes. 

Chalceus Muller and Troschel, Horse Ichth., I, 1845, 15 (angulatus), not of 

Cuvier and Valenciennes. 
Chalcinus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 258 (brachy- 

pomus) . 
Triportheus Cope, Proc. Acad. Nat, Sci. Phila., 1871, 264, pi. 8, fig. 3, and pi. 14, 

fig. 1 (flavus). 
Coscinoxyron Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 450 {culler). 

Type, Chalcinus brachypomus Cuvier and Valenciennes. 

Compressed, large-scaled, herring-like fishes; lateral line decurved; preventral 
edge compressed; pectoral large; mouth small, a pair of conical teeth in the lower 
jaw behind a series of lobed teeth; upper jaw with two series of teeth; caudal 
emarginate, the middle rays prolonged. 

The species and varieties, about thirteen in number, differ from each other 
but slightly. Within our limits one species is found about Morawhanna, another 
in the Essequibo and Demerara. They may be distinguished as follows: 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 377 

Key to the Guiana Species of Chalcinus. 
a. Six scales between the dorsal and the lateral line; twenty to twenty-five rakers on the lower limb of the 
first gill-arch; depth in the largest 3.3-3.4 in the length; caudal peduncle slender, its width equal to 

half of its deptli in the largest; lateral line 40-43; A. 27-30 elongatus. 

on. Five scales between the dorsal and the lateral line; thirty to forty-two rakers on the lower limb; depth in 
the largest 3 in the length; caudal peduncle compressed, its width equal to one-third of its depth in 
the largest; pectoral much broader than in the preceding species; lateral line 35-37; A. 26 or 27; 
origin of anal under last dorsal ray rotundatus. 

230. Chalcinus elongatus Gunther. 

Chalcinus elongatus Gunther, Catalogue, V, 1848, 342. — Steindachner, "Ich- 
thyologische Beitrage," v, 1876, 54 (Teffe; Peruvian Amazon); "Flussfische 
Siidamerika's," i, 1879, 9 (Orinoco near Ciudad Bolivar).— Garman, Bull. 
Essex Inst., XXII, 1890, 6 (Arary; Cameta; Gurupa; lea; Jose Fernandez; 
Jutahy; Lago Alexo; Lake Hyanuary; Lake Jose Assu; Manacapuru; Manaos; 
Montalegre; Obidos; Para; Porto do Moz; Rio Negro; Santarem; Silva, Lake 
Saraca; Tabatinga; Teffe; Tonantins; Villa Bella). — Eigenmann and Eigen- 
mann, Proc. U. S. Nat. Mus., XIV, 1891, 56. — Eigenmann, Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 440. 

One specimen, 213 mm. Aruka River. (C. M. Cat. No. 1999a.) 
Two specimens, 200 mm. Koreabo Rubber Plantation. (C. M. Cat. No. 

2000; I. U. Cat. No. 12247.) 

Seven specimens, 93-142 mm. Creek in Mora Passage. (C. M. Cat. No. 

2057a-c; I. U. Cat. No. 12250.) 

Ten specimens, 107-115 mm. Trenches in Morawhanna. (C. M. Cat. No. 

2058a-6; I. U. Cat. No. 12248.) 

231. Chalcinus rotundatus (Schomburgk). (Plate LV, fig. 1.) 

Chalcetis rotundatus Schomburgk, Fishes Brit. Guiana, I, 1840, 209 (Padauiri). 

Chalcinus brachypomus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 
1848, 259 (Mana; Essequibo).— Gunther, Catalogue, V, 1864, 339 (Esse- 
quibo). — Steindachner, " Ichthyologische Beitrage, v, 1876, 49 (Demerara; 
Santarem; Villa Bella).— Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 157 
(Apure).— Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 1449, fig. 43 (Dem- 
erara River) . 

Chalceus angulatus (not of Spix) Muller and Troschel, in Schomburgk, Reisen, 
III, 1848, 635 (Essequibo and Rupununi). 

Chalcinus guntheri Garman, Bull. Essex Inst., XXII, 1890, 4 (San Francisco). — 



378 MEMOIRS OF THE CARNEGIE MUSEUM 

Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 56. — Eigen- 

mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 440. 

One specimen, 187 mm. Wismar. (C. M. Cat. No. 2059.) 

Three specimens, 51-111 mm. Bartica. (C. M. Cat. No. 2060; I. U. Cat. 
No. 12249.) 

Thirty specimens, 110-155 mm. Crab Falls. (C. M. Cat. No. 1261a-e; 
I. U. Cat. No. 12251.) 

The caudal in some specimens is quite yellow, in others not. It is watered 
with black. 

This species was quite abundant about Rockstone. It is difficult to obtain 
except by the tedious process of angling with a minute hook. A small school came 
about the rocks where some fish were being cleaned at Crab Falls. These were 
secured. 

Subfamily Gasteropelecin;e. 
Carnegiella Eigenmann. 

Carnegiella Eigenmann, Ann. Carnegie Mus., VI, 1909, 13. 

Type, Gasteropelecus strigatus Giinther. 

Carnegiella is distinguished from Gasteropelecus by the following general 
characters: No adipose fin. Premaxillary with about nine tricuspid teeth in a 
single series; maxillary with a single large, conical tooth at its upper anterior angle. 

232. Carnegiella strigata (Giinther). (Plate LV, figs. 2, 3.) 

Gasteropelecus strigatus Gunther, Catalogue, V, 1864, 343 (habitat?). — Stein- 

dachner, "IchthyologischeBeitrage," v, 1876, 56 (Manacapurii). — Eigenmann 

and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 57. 
Carnegiella strigata Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

439. 
Gasteropelecus fasciatus Garman, Bull. Essex Inst., XXII, 1890, 10 (Saraca; 

Tabatinga). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 

1891, 57. 

Sixty-eight specimens, 20-42 mm. Maduni Creek. (C. M. Cat. No. 1296a-o; 
I. U. Cat. No. 11784.) 

Forty-three specimens, 30-37 mm. Woodland brook on Gluck Island. 
(C. M. Cat. No. 1297a-o; I. U. Cat. No. 11785.) 

Fourteen specimens, 30-39 mm. Malali. (C. M. Cat. No. 1298a-e; I. U. 
Cat. No. 11786.) 






eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 379 

Seven specimens, 33-36 mm. Tumatumari. (C. M. Cat. No. 1299a-c; 
I. U. Cat, No. 11787.) 

Sixteen specimens, 35-44 mm. Creek below Potaro Landing. (C. M. Cat. 
No. 1300a-e; I. U. Cat. No. 11788.) 

Two specimens, 30 mm. Rupununi Pan. (C. M. Cat. No. 1301.) 

Fifteen specimens, 30-36 mm. Wismar. (C. M. Cat. No. 2062a-//; I. U. 
Cat. No. 12252.) 

Twenty-four specimens, 24-39 mm. Rockstone sand-bank. (C. M. Cat. 
No. 2063a-Z; I. U. Cat. No. 12253.) 

This species is found in small woodland streams, contrasting thus with the 
species of Gasteropelecus, which are pelagic (in the larger rivers) in their habits. 

Head about 4; depth about 2; D. 10; A. 27-29; scales 30, twelve to fifteen 
pores in the lateral line, the line broken after the sixth scale; eye 3 in the distance 
from tip of chin to end of opercle. 

Easily recognized by its markings, for which see figure. 

The types of G. strigatus in the British Museum are in a bad state of preser- 
vation, but are undoubtedly identical with G. fasciatus of Garman. 

Gasteropelecus Gronow. 

Gasteropelecus Gronow, Mus. Ichth., II, 1756, 7. — Gunther, Catalogue, V, 1864, 

342. 

Type, Clupea sternicla Linnaeus. 

Short and deep; breast unduly expanded, trenchant, the pectorals very large; 
lateral line extending down to near the origin of anal; an adipose fin; a single series 
of premaxillary teeth; three large conical teeth along the margin of the maxillary. 

233. Gasteropelecus sternicla (Linnaeus). (Plate LV, fig. 4.) 

Gasteropelecus Gronow, Mus. Ichth., II, 1756, 7, No. 255, pi. 7, fig. 5 (Surinam). 

Clupea sternicla Linnaeus, Syst. Nat., ed. 10, I, 1758, 319 (Surinam). — Kxel- 
reuter, Nov. Com. Acad. Sci. Petropoli, VIII, 1761, 405, pi. 14, figs. 1-3. 

Gasteropelecus sternicla Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 
1848, 169, pi. 640 (Surinam).— Kner, Denkschr. Akad. Wiss. Wien, XVIII, 
1860, 16. — Gronow, Cat. Fish, ed. Gray, 1854, 171. — Gunther, Catalogue, V, 
1864, 342 (Essequibo).— Garman, Bull. Essex Inst., XXII, 1890, 8 (Tabatinga; 
Lago Alexo; Para; Curupira; Cudajas). — Eigenmann and Eigenmann, Proc. 
U. S. Nat. Mus., XIV, 1891, 56.— Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 
452 (Surinam).— Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 



380 MEMOIRS OF THE CARNEGIE MUSEUM 

1907, 30 (Para; Guiana). — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 439. 
Salmo gasteropelecus Pallas, Spic. Zool., VIII, 1769, 80, pi. 3, fig. 4.— Gmelin, 

Syst. Nat., I, iii, 1788, 1384.— Bloch, Ausl. Fische, III, 1785, 66, pi. 97, fig. 3.- 

Bloch and Schneider, Syst. Ichth., 1801, 418. 

Twelve specimens, 50-64 mm. Mud-flats below Wismar. (I. U. Cat. No. 
11666.) 

Thirteen specimens, 48-65 mm. Wismar. (C. M. Cat. No. HOla-c; I. U. 
Cat. No. 11667.) 

Twelve specimens, 42-52 mm. Mora Passage. (C. M. Cat. No. 1099a-c; 
I. U. Cat. No. 11668.) 

Twelve specimens, 41-51 mm. Trenches of Morawhanna. (C. M. Cat. No. 
1098a-c; I. U. Cat. No. 11669.) 

One specimen, Issorora. (C. M. Cat. No. 1100.) 

Fifteen specimens, 48-56 mm. Mud Creek in Aruka River. (C. M. Cat. 
No. 1097a-c; I. U. Cat. No. 11670.) 

Head 4-4.25; depth 1.75-2; D. 11; A. 31-33; scales 35; nineteen pores in the 
lateral line; eye 3 in the head, 1.5 in the interorbital. 

Silvery, with a dark line along base of the anal ; a dark band from upper part 

of gill-openings to the caudal; sometimes narrower lines following the rows of scales 

above this. 

Subfamily Serrasalmin^e. 

Serrasalmo Lacepede. 

Serrasalmo Lacepede, Hist. Nat. Poiss., V, 1804, 283. 

Type, Salmo rhombeus Linnseus. 

Belly trenchant, serrate; premaxillary with a single series of teeth; a series of 
triangular teeth on each side of the palate. 

Key to the Guiana Species of Serrasalmo. 

a. Caudal margined with white or hyaline; D. 15 or 16; A. 32-37; ventral serrse 28-33; head 3-)-; depth 1.6- 
1.7; cheeks with a naked area (in specimens 120 mm. long) equal to one-half of the second suborbital; 
snout blunt, shorter than the eye. A large diffuse humeral spot gymnogenys. 

an. Caudal margined with black, the base also black, the hyaline middle area decreasing with age; D. 16 or 17; 
A. 31-35; serrae 30-36; head 3; depth nearly 2; cheeks entirely covered by the second sub- 
orbital or a very narrow naked margin ; snout acute, especially in the young, at least equal to the eye 
in 176-mm. specimens; humeral spot obscure or none rhombeus. 

234. Serrasalmo gymnogenys Giinther. 
? Salmo aureus (not of Spix) Muller and Troschel, in Schomburgk, Reisen, III, 
1848, 637 (Essequibo; Rupununi). 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 381 

Serrasalmo gymnogenys Gunther, Catalogue, V, 1864, 371 (River Capin; British 
Guiana). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 
60.— Ulrey, Ann. N. Y. Acad. Sci., VII, 1895, 298 (Marajo).— ? Perugia, 
Ann. Mus. Genova, (2a), X, 1891, 650 (Resistencia, Chaco Centrale). — Pelle- 
grin, Bull. Mus. d'Hist, Nat., V, 1899, 157 (Apure). — Eigenmann, Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 442. 

Twenty-six specimens, 31-144 mm. Rockstone. (C. M. Cat. Nos. 1108a-c 
and 1122a-d; I. U. Cat. No. 11646.) 

One specimen, 57 mm. Wismar. (C. M. Cat. No. 1111.) 
One specimen, 47 mm. Tumatumari. (C. M. Cat. No. 1112a.) 
Two specimens, 37-125 mm. Crab Falls. (C. M. Cat. No. 1130a; I. U. Cat. 
No. 11647.) 

Four specimens, 104-141 mm. Below Packeoo. (C. M. Cat, No. 1133a; 
I. U. Cat. No. 11645a-o.) 

Head 3.1-3.25; depth 1.6-1.7; D. 15 or 16; A. 32-37; ventral seme 22-33, of 
which one is bifid before the anus and one grooved with two antrorse and two 
retrorse spines behind the anus; lateral line 77-80; eye 3.25 in the head, 1.3 in the 
interorbital, .6 in the snout. 

Deep; snout obliquely truncate, the chin projecting; second suborbital leaving 
from one-third to two-sevenths of the cheek naked; opercles and suborbitals pro- 
fusely striate; gill-rakers minute, about 10 + 10; teeth oblique, usually with a 
notch on one side, sometimes on both sides on those of the premaxillary; pre- 
maxillary with seven teeth, of which the third is very much smaller than the rest; 
lower jaw with seven slightly graduated teeth. 

Dorsal short, rounded, its base a little longer than its distance from the adipose; 
adipose short; caudal lunate; anal with a slight lobe in front; ventrals reaching to 
the anal groove or a little shorter; pectorals to, or a little past, the vertical from the 
origin of the ventrals. 

First few scales of the lateral line larger than the neighboring scales, becoming 
smaller on the sides than those above or below the line, but of the same number as 
there are transverse series; scales regularly imbricate. 

A large diffuse humeral spot; sides variously spotted; caudal with a basal 
V-shaped black band, increasing in width with age; opercles rosy in life, the color 
most intense on the lower corner of the opercle, the red sometimes extending over 
the lower part of the sides and breast; anal tinged with orange in front, 

I have examined one of the specimens mentioned as aureus by Muller and 
Troschel. It agrees with specimens taken by me in all but the color of the caudal, 



382 MEMOIRS OF THE CARNEGIE MUSEUM 

which, in addition to the basal band, has a submarginal black band, a narrower 
margin being hyaline. 

235. Serrasalmo rhombeus (Linnaeus). (Plate LVI, fig. 1.) 
Salmo rhombeus Linnaeus, Syst. Nat., ed. 12, I, 1766, 514 (Surinam). — Gmelin, 

Syst. Nat., I, iii, 1788, 686, No. 28.—? Bloch, Ausl. Fische, 1795, pi. 383.- 

Bloch and Schneider, Syst. Ichth., 1801, 404. — Pallas, Spic. Zool., VIII, 

1769, 57, pi. 5, fig. 3. 
Serrasalmo rhombeus Lacepede, Hist. Nat. Poiss., V, 1804, 284. — Cuvier, Mem. 

Mus. d'Hist. Nat., V, 1819, 367.— Cuvier and Valenciennes, Hist. Nat. 

Poiss., XXII, 1848, 272 (Araguay). — Muller and Troschel, in Schomburgk, 

Reisen, III, 1848, 637 (Rupununi; Takutu). — Castelnau, Anim. Am. Sud, 

Poiss., 1855, pi. 37, fig. 3.— Gunther, Catalogue, V, 1864, 369 (Essequibo; 

Surinam; Demerara). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., 

XIV, 1891, 60. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 442. 

Three specimens, 70-232 mm. Wismar. (C. M. Cat. No. 1131a-6; I. U. 
Cat. No. 11648.) 

Six specimens, 150-355 mm. Crab Falls. (C. M. Cat. Nos. 1127 and 1132; 
I. U. Cat. Nos. 11649 and 11653.) 

Two specimens, 209-295 mm. Packeoo. (C. M. Cat. No. 2224a; I. U. Cat. 
No. 11650.) 

One specimen, 110 mm. Twoca Pan. (C. M. Cat. No. 1134.) 

Seven specimens, 137-261 mm. Tumatumari. (C. M. Cat. No. 1120a-6; 
I. U. Cat. No. 11651.) 

Nine specimens, 39-57, and one 257 mm. Rockstone. (C. M. Cat. Nos. 1126a 
and 1741a-c; I. U. Cat. No. 11652.) 

Head 3; depth 1.8-2; D. 16 or 17 in the ratio of one to two; A. in two, 31; in 
four, 32; in two, 33; in five, 34; and in four, 36; lateral line 87-91. Abdominal 
serrse usually 30-33, rarely 28 or 36, of which there is one bifid before the anus and 
one grooved behind the anus. Eye 4.5 in head, 2 in interorbital, 1-1.25 in snout. 

Snout pointed, the lower jaw entering the profile; second suborbital covering 
the entire cheek or leaving a narrow naked margin; opercles and suborbitals pro- 
fusely striate; gill-rakers minute, about 10 + 10; teeth as in gymnogenys. 

Dorsal obliquely rounded, its base as long as, or longer than, its distance from 
the posterior end of the base of the adipose; caudal slightly lunate; anal margin 
very slightly concave, no anal lobe; ventrals not reaching anal groove; pectorals 
about to ventrals. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 383 

Scales a little less regular than in gymnogenys. 

Sides more or less obscurely spotted; humeral spot obscure or none; vertical 
fins nearly black; a lunate light spot, largest in the young, in the center of the 
caudal. 

236. Serrasalmo stagnatilis Schomburgk. 

" Arri' ' (of the Macusi Indians). 
Serrasalmo stagnatilis Schomburgk, Fishes Brit. Guiana, I, 1841, 222. (D. 17; 
A. 32; P. 15.) 
I am not able to place this species. 

Pygocentrus Miiller and Troschel. 

Pygocentrus Muller and Troschel, Horse Ichth., I, 1845, 20. 

Type, Serrasalmo piraya Cuvier. 

Belly trenchant, serrate; premaxillary with a single series of teeth; no teeth 
on the palate; teeth in the jaws trenchant; those of the upper jaw with a notch on 
the lateral edge; anal partly scaled. 

Key to the Guiana Species of Pygocentrus. 

a. Abdominal serra 40; depth 1.7-2; D. 18; A. 33-35; lateral line 105; interorbital a little less than half the 

length of the head; second suborbital in contact with the preopercle niger. 

aa. Abdominal serra? less than 35. 

b. Depth about 2 in the length; head heavy, about 3 in the length. D. 17-18; A. 30-33; lateral line 95- 
100; abdominal serra 24-27; snout short, very blunt; interorbital nearly half the length of the 
head; a very narrow naked area on the cheek; origin of dorsal nearly equidistant from base of 
middle caudal rays and front of eye; anal slightly falcate; sides profusely spotted; a V-shaped 
black bar on the base of the caudal; margin of caudal dark; adipose fin rayed in the adult. 

piraya. 
bb. Depth 1.6-1.75; head 3.12-3.5; D. 15 or 16; A. 32-34; lateral line 90; abdominal serra 27-33; snout 
short, blunt, 4.33 in the head; eye 3.5-4; interorbital 2.33; a narrow lens-shaped naked area on 
the cheek, not more than one-fourth as wide as the second interorbital; origin of dorsal about 
equidistant from base of middle caudal rays and front of eye. Gill-rakers minute, about fifteen 
on the lower limb; a large diffuse humeral blotch; sides with numerous small spots; caudal in 
the adult with a narrow hyaline margin, the rest of the fin black; in the young hyaline, with a 

faint basal V-shaped bar scapularis. 

bbb. Depth 1.42; head 3.33; D. 15 or 16; A. 30-33; abdominal serra 30 or 31; lateral line 73-76; snout 
pointed, equal to the eye, 3.5 in the head; interorbital 2.5 in the head; a lens-shaped naked 
area in the angle of the preopercle, nearly half as high as the second suborbital; origin of dorsal 
but little nearer to base of caudal than to tip of snout ; about eight minute gill-rakers on the lower 
arch; a prominent humeral spot; sides obscurely spotted; margin of caudal and a V-shaped 
basal band black; scales along base of anal and the anal margin black; base of anal white; 
dorsal and adipose blackish bilineatus. 



384 MEMOIRS OF THE CARNEGIE MUSEUM 

237. Pygocentrus niger (Schomburgk). 

Serrasalmo niger Schomburgk, Fishes Brit. Guiana, I, 1841, 225, pi. 18 (in streams 
between forty and one hundred and fifty miles from coast). — Gunther, 
Catalogue, V, 1864, 369. 

Pygocentrus niger Muller and Troschel, Hora? Ichth., I, 1845, 21, pi. 2, fig. 3.— 
Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 286 (Corentyn). — 
Muller and Troschel, in Schomburgk, Reisen, III, 1848, 636 (upper courses 
of all streams). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 
1891, 59. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 442. 
No specimens of this species were secured. It is said to be very abundant 

and the most voracious of the "Perais." I have examined the specimen figured 

by Muller and Troschel. It has forty abdominal serrae and its depth is equal to 

half the length. 

238. Pygocentrus piraya (Cuvier). 

"Piraya," Marcgrave, Hist, Rer. Nat. Bras., 1648, 164. 

Serrasalmo piraya Cuvier, Mem. Mus. d'Hist. Nat,, V, 1819, 368, pi. 28, fig. 4- 
Gunther, Catalogue, V, 1864, 368 (Brazil; River Cupai; Demerara).— 
Cope, Proc. Am. Philos. Soc, XI, 1870, 566 (Para).— Steindachner, "Fluss- 
fische Sudamerika's," ii, 1881, 13 (Teffe; Rio Puty). — Perugia, Ann. Mus. 
Genova, (2a), X, 1891, 51 (Villa Maria; Matto Grosso; Rio Paraguay). 

Pygocentrus piraya Muller and Troschel, Horse Ichth., I, 1845, 20. — Cuvier 
and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 291. — Muller and Tro- 
schel, in Schomburgk, Reisen, III, 1848, 636 (generally distributed in Brit. 
Guiana). — Kner, "Familie der Characinen," ii, 1859, 28. — ? Castelnau, 
Anim. Am. Sud, Poiss., 1855, 72, pi. 38, fig. 2 (Goyaz; Amazon). — Eigenmann 
and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 59.— Ulrey, Ann. N. Y. 
Acad. Sci., VII, 1895, 297 (Trocera on Tocantins). — Fowler, Proc. Acad. Nat. 
Sci. Phila., 1906, 468 (Para). — Eigenmann, Repts. Princeton Univ. Exp. Pata- 
gonia, III, 1910, 442. 

Serrasalmo (Pygocentrus) piraya Lutken, Dan. Vidensk. Selsk. Skr., (5), XII, 2, 
1875, 233 and xvii (Rio das Velhas). 

Serrasalmo piranha Agassiz, Selecta Gen. et Spec Pise. Bras., 1829, 71, pi. 28. — 
Schomburgk, Fishes Brit. Guiana, I, 1841, 221, pi. 16 (Rio Branco). 

Serrasalmo nigricans* 1 Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 72, pi. 30.— 

Muller and Troschel, in Schomburgk, Reisen, III, 1848, 636 (generally 

distributed in British Guiana). 

67 Lutken ( Vidensk. Med. Nat. For. Kjobenhavn, 1874, 238) considers this a distinct species. The 
specimen mentioned by Muller and Troschel, and now in the Berlin Museum, is P. piraya. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 385 

Pygocentrus bidorsalis (ex Natterer, MS.) Kner, "Familie der Characinen," ii, 

1854, 28. 

Thirteen specimens, 84-109 mm. Twoca Pan. (C. M. Cat. No. 1096a-d; 
I. U. Cat. No. 11639.) Collected by Wm. Grant. 

239. Pygocentrus scapularis (Gunther). 

Serrasalmo scapularis Gunther, Catalogue, V, 1864, 268 (British Guiana). — 
Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 157 (Apure). 

Pygocentrus scapularis Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 
1891, 69.— Ulrey, Ann. N. Y. Acad. Sci., VII, 1895, 297 (Marajo).— ? Eigen- 
mann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907, 35 (South Amer- 
ica). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 442. 
One specimen, 42 mm. Wismar. (C. M. Cat. No. 1110.) 
Twelve specimens, 29-44 mm. Rockstone. (C. M. Cat. No. 1104a-<2; 

I. U. Cat. No. 11644.) 

Three specimens, 159-184 mm. Crab Falls. (C. M. Cat. No. 1135a; I. U. 

Cat. No. 11638.) 

240. Pygocentrus bilineatus Eigenmann. (Plate LVI, fig. 2.) 

Pygocentrus bilineatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 47; Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 442. 
Type, 102 mm. Aruka River. (C. M. Cat. No. 1072.) 
Cotypes, 95-110 mm. Aruka River. (C. M. Cat. No. 1073; I. U. Cat. No. 

11756.) 

Cotypes, 43-56 mm. Mora Passage. (C. M. Cat. No. 1074; I. U. Cat. No. 

11757.) 

Pygopristis Mtiller and Troschel. 

Pygopristis Muller and Troschel, Horse Ichth., I, 1845, 21, pi. 9, figs. 2a and 2b. 

Type, Pygopristis fumarius Muller and Troschel (= denticulatus Cuvier). 

Belly trenchant, serrate; premaxillary with a single series of teeth; no teeth 
on the palate; teeth in the jaws serrate or lobed; anal naked except at its base; a 
procumbent dorsal spine. 

241. Pygopristis denticulatus (Cuvier). 
Serrasalmo denticulatus Cuvier, Mem. Mus. d'Hist. Nat., V, 1819, 371. — Gunther, 

Catalogue, V, 1864, 367 (British Guiana). 
Pygopristis derdiculatus Muller and Troschel, Horse Ichth., I, 1845, 21, 34, pi. 

9, fig. 1 (Guiana); in Schomburgk, Reisen, III, 1848, 637 (Essequibo ; Takutu ; 



386 MEMOIRS OF THE CARNEGIE MUSEUM 

Rupununi). — Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 297 

(Essequibo). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV. 

1891, 59. — Ulrey, Ann. N. Y. Acad. Sci., VII, 1895, 296 (Lower Amazon) .- 

Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 441. 
Pygopristis fumarius Muller and Troschel, Horse Ichth., I, 1848, 21, 35, pi. 9, 

fig. 2; in Schomburgk, Reisen, III, 1848, 637 (Rupununi; Essequibo). — Kner, 

"Familie der Characinen," ii, 1859, 27 (Rio Branco). 
Serrasabno punctatus Schomburgk, Fishes Brit. Guiana, I, 1841, 223, pi. 17. 

Twenty-three specimens, 151-234 mm. Lama Stop-Off. (C. M. Cat. 
No. 1118a-d; I. U. Cat. No. 11637.) 

Head 3.5; depth 1.66; D. 18 or 19; A. 34-38; scales with pores 87-95; eye 4 in 
head, 2 in interorbital; abdominal serrse 36 + 4, 33 + 3, 38 + 4, 31 + 4 in four 
individuals respectively. 

Pumpkin-seed shaped; snout rounded, lower jaw heavy, truncate, its anterior 
profile forming a continuous oblique line with the snout. Second suborbital leav- 
ing four-tenths of the cheeks naked ; opercular bones and suborbitals but little striate ; 
mouth small; teeth nearly symmetrical, with a central lobe and two much smaller 
lobes on each side; six teeth on each premaxillary, in a single series, the third tooth 
much smaller than the rest. 

Gill-rakers 9 + 9, small. 

Dorsal broadly rounded, its base equal to its distance from the caudal; adipose 
short; caudal lobes pointed; anal with its first two or three developed rays slightly 
prolonged, the rest of the margin of the fin nearly straight; ventrals reaching anal 
groove, pectorals not quite to ventrals. 

Lateral line decurved; anterior scales of the lateral line largest; rows of scales 
along the middle of the sides more numerous than the pores in the lateral line, the 
pores corresponding to the rows of scales on the caudal peduncle and over the 
posterior fourth of the anal; a wide naked area from the dorsal to the occipital. 

Dorsal faintly spotted. Iridescent steel-blue above. Pectorals, ventrals, 
and most of the anal brick-red; opercle orange; a narrow margin of the caudal 
and anal colorless; caudal submarginally orange, ranging to lemon-yellow and olive. 

Subfamily Mylin^e. 
Catoprion Muller and Troschel. 
Catoprion Muller and Troschel, Horse Ichth., I, 1845, 22. 
Type, Serrasabno mento Cuvier. 

Belly serrate; premaxillary with two series of teeth; mandible with a single 
series of teeth; dorsal falcate; lower jaw projecting, the chin entering the profile. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 387 

242. Catoprion mento (Cuvier). (Plate LVI, fig. 3.) 
Serrasalmo mento Cuvier, Mem. Mus. d'Hist. Nat., V, 1819, 369, pi. 28, fig. 3. 
Catoprion mento Muller and Troschel, Horse Ichth., I, 1845, 22, pi. 2, fig. 5.— 
Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 304. — Muller 
and Troschel, in Schomburgk, Reisen, III, 1848, 637 (Lake Amucu). — Kner, 
"Familie der Characinen," ii, 1859, 26 (Rio Guapore; Rio Negro). — Gunther, 
Catalogue, V, 1864, 379. — Eigenmann and Eigenmann, Proc. U. S. Nat. 
Mus., XIV, 1891, 61. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 
III, 1910, 442. 
Mylesinus macropterus Ulrey, Ann. N. Y. Acad. Sci., VIII, 1895, 296 (Brazil). 
One specimen, 148 mm. Rockstone. (C. M. Cat. No. 1739.) 
Three specimens, 75-79 mm. Konawaruk. (C. M. Cat. No. 1740a-6; I. U. 
Cat. No. 11640.) 

Head 3.66-4; depth 1.4-1.75; D. 16 or 17; A. 37-39; lateral line 89-94; ven- 
tral serrse 33; eye 2.66 in the head, 1 in the interorbital, .75 in the snout. 

Rhomboidal; snout very short, sharply pointed, lower jaw much projecting, 
entering profile; premaxillary with two large, antrorse, conical teeth in an outer 
series, and three much smaller teeth forming an inner series. 

Gill-rakers long and slender, 9 + 14. Lateral line with a sag to below the 
end of the dorsal ; anal entirely naked. Dorsal and anal falcate, the dorsal reaching 
beyond the middle of the upper caudal lobe, and the anal lobe to the last ray of the 
dorsal in extreme cases; adipose more than half the length of the dorsal; caudal 
forked. Silvery, anal lobe pink at base; caudal with a basal, V-shaped black spot. 

Mylesinus Cuvier and Valenciennes. 
Mylesinus Cuvier and Valenciennes, Hist. Nat. Poiss., 1848, 234. 

Type, Mylesinus schomburgkii Cuvier and Valenciennes. 

Abdomen rounded in front of the ventrals, serrate behind them; premaxillary 
with six or seven teeth in each side in the front series, of which the first and (if 
seven) the last are smallest; in the second series two teeth of similar form behind 
the space between the second and third teeth of the first series and close to them; 
mandible with seven to thirteen teeth on each side; base of anal scaled. Teeth 
all flat, thin incisors. Premaxillary teeth three-lobed, the middle lobe much the 
broader; teeth of the lower jaw flat, rounded, with a notch in front which receives 
a lobe of the preceding tooth. Dorsal rays prolonged, filiform; jaws nearly equal; 
anal bilobed; rays in both sexes (during breeding season ?) bifid, one fork turned 
to the right, the other to the left. 



388 MEMOIRS OF THE CARNEGIE MUSEUM 

243. Mylesinus schomburgki Cuvier and Valenciennes. 
Mylesinus schomburgkii Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 
235, pi. 644 (based on a head and drawing by Schomburgk) . — Kner, "Familie 
der Characinen," ii, 1859, 24, pi. 3, fig. 7 (Rio Vaupe). — Gunther, Catalogue, 
V, 1864, 366.— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 
1891, 59. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 442. 
No specimens were secured by me. 

D. 21-22; A. 32-35; depth 2; head 4; scales 30-100-24; eight to ten ab- 
dominal serra? behind the ventrals; posterior half of the anal produced into a lobe; 
each of the fifteen or sixteen posterior anal rays terminating in two branches, one 
being bent towards the right, the other towards the left; base of anal scaled; jaws 
equal; maxillary about reaching the eye. 

This species, based on a drawing by Schomburgk, may not have been taken 
within the region covered by this paper. I examined a specimen in the Paris 

Museum. 

Acnodon Eigenmann. 

Acnodon Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1904, 147 (oligo- 

canthus) . 

Type, Myleus oligocanthus Miiller and Troschel. 

No spines in front of the ventrals; belly serrate behind; caudal forked; anal 
falcate or bilobed, entirely naked. Gill-rakers 11 + 11, those of the upper arch 
very much shorter than those of the lower, the lower one-fourth the diameter of 
the eye. Four middle teeth of the inner series of the premaxillary with a V-shaped 
cutting edge; dorsal rays not filiform. 

244. Acnodon oligocanthus (Miiller and Troschel). 
Myleus oligocanthus Muller and Troschel, Horse Ichth., I, 1845, 40, pi. 8, fig. 

4 (Surinam). 
Myletes oligocanthus Gunther, Catalogue, V, 1864, 378 (Demerara). — Eigenmann 

and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 61.— Ulrey, Ann. N. Y. 

Acad. Sci., VIII, 1895, 299 (Brazil). 
Acnodon oligocanthus Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 

1904, 147; Repts. Princeton Univ. Exp. Patagonia, III, 1910, 443. 

No specimens were secured. I have examined the type in the Berlin Museum 
from Surinam. 

D. 18-19; A. 36-39; depth 2+ ; head 4; eight or nine serrse between ventral 
and vent; eye 2.5 in the head, interorbital 3.5; dorsal elevated anteriorly; adipose 
small; scales about 34-85-27. Coloration uniform. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 389 

Metynnis Cope. 

Metynnis Cope, Proc. Am. Philos. Soc, XVII, 1878, 692 iluna). 

Sedkina Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 478 (lippincottianus). 

Type, Metynnis luna Cope. 

Belly trenchant, serrate; premaxillary with two series of teeth; mandible with 
a pair of teeth behind the front series; a procumbent predorsal spine; adipose fin 
more than half the length of the dorsal; free margin of anal slightly convex or with 
a lobe in front or sinuate; dorsal falcate. 

Key to the Guiana Species of Metynnis. 

a. Gill-rakers 14 + 18-20, about one-fourth the length- of the eye; adipose twice as long as its distance from 
the dorsal, or longer; caudal lunate; anal low, its margin sinuate, the rays at the beginning of the last 
third about half as long as eye. A. 40-43; D. 19-20; abdominal serrse 27-33; depth 1.1-1.24. Sides 

with obscure cross-bands, a humeral spot hypsauchen. 

aa. Gill-rakers 7-12 + 11-13, about one-sixth to one-fourth the length of the eye; adipose but little longer than 
its distance from the dorsal. Caudal very slightly emarginate; anal high, rays of the beginning 
of the last third equal to eye. A. 37-40; D. 17-21; seme 31-35; depth 1.22-1.3; head 3.66; dorsal 
in the larger spotted; dorsal, adipose, caudal, and anal margined with dusky. A dark oblique bar 
extending from near end of pectoral up toward origin of dorsal, broken into two spots frequently, 
sides obscurely spotted maculatus. 

245. Metynnis hypsauchen (Muller and Troschel). 

Myletes hypsauchen Muller and Troschel, Horse Ichth., I, 1845, 38, pi. 10, fig. 
1 (Essequibo; Guiana). — Ctjvier and Valenciennes, Hist. Nat. Poiss., XXII, 
1848, 219 (Amazon). — Muller and Troschel, in Schomburgk, Reisen, III, 
1848, 637 (Tapacuma Lake). — Kner, "Familie der Characinen," ii, 1859, 18 
(Caigara; Marabitanos) . — Gunther, Catalogue, V, 1864, 376 (Essequibo 
River). — Steindachner, "Flussfische Stidamerika's," ii, 1881, 28 (Santarem; 
Teffe; Rio Trombetas; Rio Guapore); iv, 1882, 16 (Huallaga). — Eigenmann 
and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 61. — ? Boulenger, 
Trans. Zool. Soc. London, XIV, 1896, 37 (Descalvados) ; ? Boll. Mus. Zool. 
ed Anat. Comp. Torino, XV, 1900, — (near Corumba). — Eigenmann and 
Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907, 35 (South America).— Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 443. 
I have examined the types and: 
Eleven specimens, 60-110 mm. Rockstone. (C. M. Cat. No. 1125a-d; I. U. 

Cat. No. 11641.) 

Four specimens, 61-70 mm. Twoca Pan. (C. M. Cat. No. 1124a; I. U. Cat. 

No. 11642). 



390 MEMOIRS OF THE CARNEGIE MUSEUM 

One specimen, 44 mm. Bartica. (C. M. Cat. No. 2460a.) 
The characters of the species are given in the key. 

246. Metynnis maculatus (Kner). (Plate LVII, fig. 1.) 

Myletes maculatus Kner, "Familie der Characinen," ii, 1859, 18, pi. 2, fig. 5 (Rio 
Guapore). — Gunther, Catalogue, V, 1864, 377. — Steindachner, "Flussfische 
Siidamerika's," ii, 1881, 28 (Maroni River, Guiana). — Eigenmann and Eigen- 
mann, Proc. U. S. Nat. Mus., XIV, 1891, 61.—? Perugia, Ann. Mus. Genova, 
(2), XVIII, 1897, 26 (Reyes; Rio Beni).— Vaillant, Bull. Mus. d'Hist. Nat., 
V, 1899, 154 (Carsevenne). 

Methynnis maculatus Berg, An. Mus. Nac. Buenos Aires, V, 1897, 286 (San Pedro 
on Rio Parana). 

Metynnis maculatus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 
1910, 443. 
Six specimens, 144-176 mm. Lama Stop-Off. (C. M. Cat. No. 1119a-6; 

I. U. Cat. No. 11661.) 

One specimen, 65 mm. Rockstone. (C. M. Cat. No. 2216.) 

Six specimens, 76-83 mm. Twoca Pan. (C. M. Cat. No. 1123a-b; I. U. 

Cat. No. 11643.) 

Iridescent steel-blue above; opercles very bright orange; lower parts white, 

tinged with orange; anal orange in front, fading out behind; margin of caudal 

bluish, with a submarginal orange band, rest of caudal olive; pectorals yellowish. 

Myloplus Gill. 

Myletes (not of Cuvier) Muller and Troschel, Horse Ichth., I, 1845, 22 (asterias). 

— Gunther, Catalogue, V, 1864, 372. 
Myloplus Gill, Proc. U. S. Nat. Mus., XVIII, 1895, 214, substitute for Myletes 

of Muller and Troschel and of Gunther (asterias by implication). 

Type, Myletes asterias Muller and Troschel. 

Belly trenchant, serrate; premaxillary with two series of teeth, separated from 
each other; mandible with a pair of conical teeth; a procumbent predorsal spine; 
adipose fin short; gill-rakers short, lanceolate; dorsal rays 21-31; cheeks largely 
naked. 

Anal frequently (always ?) bilobed in the male, falcate in the female. 

On account of such a comparatively small number of the species of this genus 
having been secured no description beyond a brief key to the species is here at- 
tempted. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 391 

It is very probable that the anal in the males of all of the species, certainly in 
some of them, is bilobed, i. e., the anterior rays and those near the middle of the fin 
are prolonged. The anal in the female is falcate in all of the species so far placed 
on record. 

Key to the Guiana Species of Myloplus. 
a. Sides with an oblique cross-band; serrae 33-35; D. 23-25, the anterior rays filiform in the male; the anal 

bilobed, falcate in female schomburgki. 58 

aa. Sides plain. 

b. D. 26-31; depth 1.25-1.6 in the length, distance between origin of anal and origin of dorsal 1.3 in the 
length without the head; adipose fin .5 or .6 of the length of the eye; base of last dorsal ray 
about equidistant from end of lateral line and base of fourth to eighth ray. Anal falcate, 36-44; 

serrse 37-49. Origin of dorsal nearer to snout than to end of lateral line rubripinnis. 

66. D. 24 or 25; A. 35 or 36; depth 1.5 in the length; adipose fin .8 of the length of the eye or equal to it; 
base of dorsal 3.5-3.8 in the length; base of last dorsal ray equidistant from the base of the first 

ray and the eleventh scale from the end of the lateral line; sense 37-41 rhomboidalis. 

aaa. Sides with orange spots; D. 27-31; A. 35-40; depth 1.66 in the length; distance from origin of anal to 
origin of dorsal 1.5 in the length, much less than length of head; origin of the dorsal nearer to end 
of lateral line than to tip of snout. Serrse 36-3S; anal falcate in the female, bilobed in the male. 

asterias. 

247. Myloplus rubripinnis (Midler and Troschel). (Plate LVII, fig. 2.) 

Myletes rubripinnis Muller and Troschel, Hora Ichth., I, 1845, 28, pi. 9, fig. 3 

(Essequibo); in Schomburgk, Reisen, III, 1848, 637 (Essequibo). — Gunther, 

Catalogue, V, 1864, 373 (Essequibo). — Eigenmann and Eigenmann, Proc. 

U. S. Nat. Mus., XIV, 1891, 60. 
Myleus rubripinnis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

443. 

Five specimens, 72-97 mm. Crab Falls. (C. M. Cat. No. 1121a-6; I. U. 
Cat. No. 11662.) 

Six specimens, 124-365 mm. Crab Falls. (C. M. Cat. Nos. 1128 and 1129; 
I. U. Cat. No. 11657.) 

Three specimens, 139-252 mm. Rockstone. (C. M. Cat. No. 2218; I. U. 
Cat, No. 11656.) 

68 Mylophus schomburgki (Jardine). 

Tetragonopterus schomburgk ii Jardine, in Schomburgk, Fishes Brit, Guiana, I, 1841, 243, pi. 22 (Rio Negro). 

Myletes schomburgkii (not of Muller and Troschel) CuviERand Valenciennes, Hist. Nat. Poiss., XXII, 1848, 
212 (Surinam). — Steindachner, " Ichthyologische Bcitrage," v, 1876,86. — Eigenmann, Repts. Prince- 
ton Univ. Exp. Patagonia, III, 1910, 443. 

Myletes palometa Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1S4S, 214 (Orinoco). — Gunther, 
Catalogue, V, 1864, 372. 
No specimens were secured and there is no authentic record of its having been taken in the Essequibo. 



392 MEMOIRS OF THE CARNEGIE MUSEUM 

One specimen, 95 mm. Bartica. (C. M. Cat. No. 2223.) 

One specimen, 157 mm. Malali. (C. M. Cat. No. 2222a.) 

One specimen, 325 mm. Tumatumari. (I. U. Cat. No. 11658.) 

Head 3.75; depth 1.28-1.4; D. 26-28; A. 36-44; seme 33-41 + 4-8; scales 

88 with pores. Eye 2.75 in the head, 2 in the interorbital. 

All the specimens so far recorded have the anal falcate. The larger of the 

types in Berlin is but 120 mm. long. 

248. Myloplus asterias (Muller and Troschel). (Plate LVII, fig. 3.) 

Myletes asterias Muller and Troschel, Horse Ichth., I, 1845, 36, pi. 10, fig. 2 
(Essequibo and Mazaruni) ; in Schomburgk, Reisen, III, 1848, 638 (Essequibo 
and Mazaruni near cascades). — Gunther, Catalogue, V, 1864, 373 (Esse- 
quibo). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 
60. — Boulenger, Trans. Zool. Soc. London, XIV, 1896, 37 (Descalvados). 

Myleus asterias Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 443. 

Myletes ellipticus Gunther, Catalogue, V, 1864, 375 (Essequibo). — Eigenmann 
and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 61. 

Myleus ellipticus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
443. 
Two specimens, males, 212-190 mm. Malali. (C. M. Cat. No. 2217a; I. U. 

Cat. No. 11660a.) 

Head 3.66; depth 1.5; D. 27; A. 35-39; serrse 44 + 8 double ones and 37 + 

11; eighty-seven to eighty-nine scales with pores, about ten more rows of scales 

than indicated by pores; eye 2.6-2.75 in the head, 1.5-2 in the interorbital, .7 

in the snout. 

For the general characters of this species, see the figure. I have examined the 

type of ellipticus in the British Museum, and a specimen collected by Ehrhardt. 

The type is soft and faded, but the second specimen is in a good state of preservation. 

They are males. 

Two specimens of M. asterias in the British Museum, as well as two (including 

the type) in the Berlin Museum, are females, and have the anal falcate. 

249. Myloplus rhomboidalis (Cuvier). (Plate LVIII, figs. 1-4.) 

Mijletes rhomboidalis Cuvier, Mem. Mus. d'Hist. Nat., IV, 1818, 449, pi. 22, fig. 3. 
—Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 210. — Castel- 
nau, Anim. Am. Sud, Poiss., 1855, 67 (Amazon). — Gunther, Catalogue, V, 
1864, 373 (Essequibo; Guiana). — Eigenmann and Eigenmann, Proc. U. S. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 393 

Nat. Mus., XIV, 1891, 60.— Ulrey, Ann. N. Y. Acad. Sci., VII, 1895, 299 

(Brazil). 
Mijlcus rhomboidalis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

1910, 443. 
Tetragonopterus latus Schomburgk, Fishes Brit. Guiana, I, 1841, 241. 
Myletes latus Muller and Troschel, Horse Ichth., I, 1845, 37; in Schomburgk, 

Rcisen, III, 1848, 638 (all rivers). 

One specimen, 20 mm. Konawaruk. (C. M. Cat. No. 2462a.) 

Two specimens, 130-219 mm. Tumatumari. (C. M. Cat. No. 1490a; I. U. 
Cat. No. 11659.) 

One specimen, 19 mm. Gluck Island. (C. M. Cat. No. 2463a.) 

Seven specimens, the largest 47 mm. Warraputa. (C. M. Cat. No. 1103a-c; 
I. U. Cat. No. 11664.) 

Eight specimens, the largest 40 mm. Amatuk. (C. M. Cat. No. 1105a-6; 
I. U. Cat. No. 11663.) 

One specimen, 59 mm. Crab Falls. (C. M. Cat. No. 2221a.) 

One specimen, about 104 mm. Bartica. (C. M. Cat. No. 2461.) 

I have also examined the specimens in the British Museum, the largest of 
which is 260 mm., and those in the Berlin Museum under the head of lahis. 

Most of the specimens secured were young from the cataracts at Warraputa, 
Amatuk, and Crab Falls. 

Head 3.66; depth 1.5; D. 23-24; A. 35 and 36; seme 37-41; eye 2.75 in the 
head, 1.5 in the interorbital. Most readily distinguished by the short-rayed dorsal 
and long adipose dorsal. 

Myleus Muller and Troschel. 
Myleus Muller and Troschel, Horse Ichth., I, 1845, 24 (setiger = pacu). 
Tometes Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 226 (trilobatus 

= pacu). 

Type, Myleus setiger Muller and Troschel = Myletes pacu Schomburgk. 

Belly trenchant, serrate, the serrse becoming obscure with age; the two pre- 
maxillary series of teeth close together, the outer incisor-like; mandible with a 
pair of conical teeth in front; anal falcate in the female, bilobed in the male; 
dorsal rays prolonged into filaments in the male. 

250. Myleus pacu (Schomburgk). (Plate LIX, figs. 1-6.) 

Myletes pacu Schomburgk, Fishes Brit. Guiana, I, 1841, 236, pis. 20-21. — Muller 
and Troschel, in Schomburgk, Reisen, III, 1848, 644. 



394 MEMOIRS OF THE CARNEGIE MUSEUM 

Myleus setiger Muller and Troschel, Horse Ichth., I, 1845, 39, pi. 11, fig. l—lh 
(Essequibo; Santarem); in Schomburgk, Reisen, III, 1848, 638 (Essequibo 
below the cascades). — Eigenmann, Repts. Princeton Univ. Exp. Pagatonia, 
III, 1910, 443. 

Myletes setiger Kner, "Familie der Characinen," ii, 1859, pi. 2, fig. 6 (Matto 
Grosso).— Gunther, Catalogue, V, 1891, 378 (British Guiana).— Eigenmann 
and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 61. 

Myletes schomburgkii (not of Jardine) Muller and Troschel, Horse Ichth., I, 
1845, 37. — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 637 
(Rupununi; Takutu; Zuraima; Savannah swamps). — Gunther, Catalogue, V, 
1864, 372, part,— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 
1891, 60.— Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910,443. 

Myletes divaricatus Cuvier and Valenciennes, Hist, Nat, Poiss., XXII, 1848, 215 
(Essequibo).— Kner, "Familie der Characinen," ii, 1859, 15.— Gunther, 
Catalogue, V, 1864, 376. 

Myletes diodyxodon Cuvier and Valenciennes, Hist, Nat. Poiss., XXII, 1848, 
222. — Castelnau, Anim. Am. Sud, Poiss., 1855, pi. 34, fig. 1 (Amazon). 

Tometes trilobatus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 226 
(Cayenne). 

Myletes trilobcdus Gunther, Catalogue, V, 1864, 377.— Eigenmann and Eigen- 
mann, Proc. U. S. Nat, Mus., XIV, 1891, 61. 

Myletes filosus (ex Heckel, MS.) Kner, "Familie der Characinen," ii, 1859, 19. 
Schomburgk preserved no specimen of his "Pacu" to serve as the type for this 

species. There is, however, no doubt about what fish he figured and described. 

Muller and Troschel, whose specimens I have examined, described the male of 

this species as Myleus setiger and referred the female to Schomburgk's schomburgkii, 

which is quite a different fish. 

I have also examined the various types of Cuvier and Valenciennes. The type of 

Myletes divaricatus is undoubtedly, and that of Tometes trilobatus is very probably,- 

also of this species. Both types are dried, divaricatus apparently a half skeleton 

while trilobatus is a stuffed skin. They may or may not have their original 

shape. The depth is 2 in the length without the snout in one, and 2 without the 

snout and eye in the other. 

This is the most famous of the food-fishes of Guiana. It is abundant about 

the falls, where it feeds on the weeds growing on the rocks. 

Four specimens, one female, 515 mm., and three males, 490-563 mm. Falls of 

the Mazaruni. Mr. Fowler. (C. M. Cat. Nos. 2491 and 2492.) 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 395 

Fifteen specimens, 21-55 mm. Warraputa. (C. M. Cat. Nos. 1102a-d and 
2220a-d; I. U. Cat. No. 11665.) 

Head 3.8; depth 1.7-2; D. 23-25; A. 36-38; scales 43 to about 95-110-34 
(the latter counted in a series above the lateral line); eye about 4.7 in the head; 
abdominal serrse 31 -f 4. 

Sides irregularly blotched with black in the adult. 

The young specimens were taken with poison in one of the shutes of the 
Warraputa cataracts. It is probable therefore that the "Pacu" spawns above the 
cataracts. 

Subfamily Cynodontin^e. 

Cynodon Spix. 

Cynodon Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 76 (vulpinus and gibbus). 

Type, Cynodon gibbus Spix. 

This species may be recognized among its relatives by its elongate anal. A 
fantastic fish, the appearance of which suggests a "grafting" of two types, one type 
being represented from the head to behind the shoulder-girdle, the other from behind 
the shoulder-girdle to the tail. 

This genus has not before been reported from Guiana. 

251. Cynodon gibbus Spix. 

Cynodon gibbus Spix, Selecta Gen. et Spec. Pise. Bras., 1829, pi. 27.— 
Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 333 (Amazon).— 
Castelnau, Anim. Am. Sud, Poiss., 1885,75 (Amazon). — Kner, "Familie der 
Characinen," ii, 1859, 46 (Rio Branco). — Gunther, Catalogue, V, 1864, 359. 
—Cope, Proc. Am. Philos. Soc, XVII, 1878, 688 (Peruvian Amazon). — Stein- 
dachner, "Flussfische Sudamerika's," iv, 1882, 15 (Rio Huallaga). — Eigen- 
mann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 59. — Perugia, 
Ann. Mus. Genova, (2), XVIII, 1897, 26 (Rio Mamore).— Fowler, Proc. Acad. 
Nat. Sci. Phila,, 1906, 467. — Eigenmann, Repts. Princeton Univ. Exp. 
Patagonia, III, 1910, 444. 
Five specimens, 115-230 mm. Wismar. (C. M. Cat. Nos. 1249a and 1998a-6; 

I. U. Cat. No. 12245.) 

Two specimens, 240-325 mm. Malali. (C. M. Cat. No. 1997a; I. U. Cat, 

No. 12246.) 

Head 4.75-5; depth 3.4; D. 12; A. 77; scales 145-163 in a series above the 

lateral line. Eye 1 in snout, 3.8 in head, 1 in intcrorbital. 

Compressed, breast trenchant; body deep at the pectorals, long, tapering to 



396 MEMOIRS OF THE CARNEGIE MUSEUM 

the caudal; skull very short above, the profile depressed over the eyes; mouth very 
oblique; maxillary slipping under the suborbital; maxillary-premaxillary border 
three-fourths of the length of the head; gill-rakers short, tubercular, about eighteen 
on the lower arch. 

Scales cycloid, very small along the back, becoming larger downward; basal 
half of anal scaled; caudal naked; lateral line straight. 

Pectorals very large, wing-like; ventrals about one-fourth as long as the pec- 
torals; anal very long, its margin straight, its origin equidistant from the angle of 
the mouth and the end of the anal ; dorsal small, over the anterior part of the anal ; 
caudal lunate, its middle rays prolonged. Iridescent silvery ; a large black humeral 

spot. 

Hydrolycus Mtiller and Troschel. 

Hydrolycus Muller and Troschel, Horse Ichth., I, 1845, 18. 

Type, Hydrocyon scomberoides Cuvier. 

Distinguished by its rounded caudal and short anal. Dorsal in advance of 
anal; anal and caudal scaled; scales with serrate margins. 

Of the three species of this genus one is said to occur in all the rivers of Guiana. 
We did not secure specimens. 

252. Hydrolycus scomberoides (Cuvier). 
Hydrocyon scomberoides Cuvier, Mem. Mus. d'Hist. Nat., V, 1819, 357, pi. 27, 

fig. 2. 
H ydrocynus scomberoides Cuvier, Regne Animal, II, 1817, 168. 
Hydrolycus scomberoides Muller and Troschel, Horse Ichth., I, 1848, 19, pi. 5, 

fig. 2; in Schomburgk, Reisen, III, 1848, 636 (all streams). — Eigenmann and 

Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 59.— Fowler, Proc. Acad. 

Nat. Sci. Phila., 1906, 466. — Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 444. 
Cynodon scomberoides Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

324 (Essequibo).— Kner, " Familie der Characinen," ii, 1848, 45 (Bananeira). 

— Castelnau, Anim. Am. Sud, Poiss., 1855, 75, pi. 39, fig. 2 (Araguay; Lac 

de Jules).— Gunther, Catalogue, V, 1864, 358 (River Capin, British Guiana). 
-Peters, MB. Akad. Wiss. Berlin, 1877, 472 (Calabozo).— Steindachner, 

"Flussfische Slidamerika's," iv, 1882, 15 (Iquitos, Amazonas). 
? Hydroscion ? armatus Schomburgk, Fishes Brit, Guiana, I, 1841, 247, pi. 25fo's. 69 

69 There are two plates marked 25. Only the second belongs to this species. The description evidently 
refers to this species. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 397 

Head 4.5; depth 3.5-4; D. 12; A. 33-40. 

Similar to Cynodon gibbus in general appearance. 

Although reported as occurring in all the rivers of Guiana no specimens of this 
species were seen. A specimen 228 mm. long in the British Museum was presented 
by Robert Schomburgk. Another over 500 mm. long is in the Berlin Museum. 
It would seem from these specimens that the caudal is slightly emarginate. 

Mr. Ellis has recently taken one on Gluck Island. 

Subfamily Characin^e. 
Exodon Muller and Troschel. 
Exodon Muller and Troschel, Horse Ichth., I, 1S45, 31 {paradoxus). 
Hystricodon Gunther, Catalogue, V, 1864, 549 (paradoxus). 
Type, Exodon paradoxus Muller and Troschel. 

Entire dorsal in front of the vertical from the anal; anal moderate; lateral 
line complete; teeth conical, in a double series in the mandible, those of the outer 
series largest, irregular, divergent; a pair of large tooth-like prongs extending 
forward on tip of snout, 

253. Exodon paradoxus Muller and Troschel. (Plate LX, fig. 1.) 

Exodon paradoxus Muller and Troschel, Horse Ichth., I, 1845, 31, pi. 4, fig. 1 
(Essequibo); in Schomburgk, Reisen, III, 1848, 635 (Upper Rupununi). — 
Kner, "Familie der Characinen," ii, 1859, 38 (Rio Branco). — Eigenmann 
and Eigenmann, Proc. U. S. Nat, Mus./XIV, 1891, 58.— Eigenmann, Repts. 
Princeton Univ. Exp. Patagonia, III, 1910, 446. 

Epicyrtus paradoxus Castelnau, Anim. Am. Sud, Poiss., 1855, 60 (Caixas; Ara- 
guay; Amazon). 

Epicyrtus exodon Cuvier and Valenciennes, Hist. Nat, Poiss., XXII, 1848, 46. 

Hystricodon paradoxus Gunther, Catalogue, V, 1864, 349. 

One specimen, 75 mm. Rupununi. (C. M. Cat. No. 2145.) 

This species differs from all other characins in its large black spots on the 

side in front of the dorsal and covering the caudal peduncle. 

Head 3.5; depth 2.75-3; D. 10 or 11; A. 19-22; scales 9-36-6. Eye 1 in 

snout, 3.5 in head, 1.5 in interorbital. 

Dorsal and ventral profiles equally arched, without humps or depressions; 

ventral area rounded, without a distinct median scries of scales; predorsal area 

rounded, with a median series of about eleven scales. Occipital process extending 

one-sixth of the way to the dorsal; fontanel reaching to above the middle of the eye; 



398 MEMOIRS OF THE CARNEGIE MUSEUM 

second suborbital leaving a naked area between it and the maxillary, none between 
it and the limbs of the preopercle. Snout pointed, mouth little oblique, a distinct 
angle between the horizontal premaxillary and the maxillary; premaxillary- 
maxillary border half as long as the head; maxillary with about eight conical 
teeth along its entire anterior border, one of the teeth directed forward and out- 
ward; premaxillary with a forward directed process at its tip, an outer series of 
two and inner series of six subequal conical teeth, none of which are canines ; lower 
jaw with an inner series of subequal, irregularly graduate teeth, and an outer 
series of four large conical teeth on each side, the second of which is directed for- 
ward as well as upward. 

Gill-rakers 7 + 9, all but the lowermost one of the upper arch minute, those 
of the lower arch about one-fourth of the orbit. 

Scales regularly imbricate, smallest on the breast, each with several longi- 
tudinal striae; fins naked; lateral line decurved in front. 

Origin of dorsal a little nearer to base of caudal than to tip of snout, its highest 
ray 4.5 in the length; caudal lobes about 3 in the length; anal emarginate, its 
origin nearer to caudal than to base of pectoral; ventrals reaching anal, pectorals 
to ventrals. 

Upper parts and caudal bright yellow, a bright silvery band between the 
black spots, lower parts suffused with red; dorsal red in the middle, then yellow; 
an orange streak from base of first anal ray to the tip of the third or fourth; middle 
half of second and third ventral rays red. A large black spot covering more than 
thirty scales, its center over the ninth scale of the lateral line; a large black spot 
covering the entire sides of the caudal peduncle. 

Rceboides Gtinther. 
Rceboides Gunther, Catalogue, V, 1864, 345 (mierolepis and guatemalensis) .— 

Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 57. 
Rhceboides Berg, Com. Mus. Nac. Buenos Aires, 5, 1899, 94. 
Cynocharax Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 457 (affinis). 

Type, Epicyrtus mierolepis Reinhardt. 

Teeth all small, conical or tricuspid, in a single series on the maxillary and 
sides of the mandibles, in two imperfect series on the premaxillary and sometimes 
the front of the mandible; middle teeth of premaxillary slightly enlarged; maxil- 
lary with teeth along its entire margin or not; anterior teeth of the mandible and 
one on each corner slightly enlarged; several larger tooth-like prongs projecting 
forward from the upper jaw at the margin of the lip; maxillary frequently with 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 399 

similar prongs; lower jaw with two or four prongs directed forward; cheeks almost 
entirely covered by the suborbitals; gill-membrane free from the isthmus; gill- 
rakers similar on the two limbs, strong, few, long; pharyngeals with short, stiff 
rakers; scales small, cycloid; dorsal over origin of anal, which is very long, of forty- 
two to fifty-seven rays; pectorals overlapping vcntrals; breast flat; tongue free. 
Lateral line complete; alimentary canal short. 

254. Roeboides thurni sp. nov. (Plate LX, fig. 2.) 

Type, 104 mm. Rockstone sand-bank. (Carnegie Museum Catalog of 
Fishes No. 2149.) 

Cotypes, four specimens, 45-115 mm. Rockstone sand-bank. (C. M. Cat. 
No. 2150a-6; I. U. Cat. No. 12320.) 

Cotypes, nine specimens, 63-87 mm. Crab Falls. (C. M. Cat. No. 2151a-d; 
I. U. Cat. No. 12321.) 

Head 3.6-3.75; depth 2.75-3.2; D. 11; A. 47-51, most frequently 48 or 49; 
scales 17 to 19-72 to 80-10 to 13; eye 1-1.3 in the snout, 3.3-4 in the head, 1 in 
the interorbital. 

Elongate; profile oblique, nearly straight to base of the occipital process, 
then abruptly rising in an arch to the dorsal; preventral area rounded, without 
a regular median series of scales; post-ventral area with a median keel; predorsal 
area narrow, the median line in part naked; about thirty scales between the dorsal 
and the occipital crest; occipital crest reaching four-tenths of the way to the dorsal; 
fontanel reaching to above the anterior margin of the eye. 

Opercles, suborbitals, and bones of the head wrinkled. Middle of opercle 
drawn out into a flat spine. Snout pointed, premaxillary horizontal, meeting 
the maxillary at an angle; premaxillary-maxillary border 2 in the head; maxillary 
with about eight stout conical teeth with divergent points; premaxillary with 
several conical thorns directed outward and forward, of which the anterior 
is the largest, also two irregular series of small conical teeth ; lower jaw with thorns 
directed forward and outward and a single series of teeth, of which the sixth tooth 
is the largest, the first next in size and the remainder (about twenty) small, conical. 

Gill-rakers 7 + 10. 

Scales small, cycloid, without stria?. Fins naked; lateral line straight. 

Origin of dorsal in advance of the middle, the fin small, the highest ray 4 in 
the length; caudal small, the lobes 4 in the length; anal very long, slightly emar- 
ginate, its origin equidistant from the snout and its end, a little nearer to the snout 
than to the dorsal; ventrals reaching anal; pectorals beyond the middle of the 
ventrals. 



400 MEMOIRS OF THE CARNEGIE MUSEUM 

An intense black spot, about as large as the pupil, on the second to fourth or 

fifth row of scales above the lateral line, and from above the sixth to the ninth pore 

of the latter; a diffuse dark area at the end of the caudal peduncle; a silvery 

lateral band. 

Charax Scopoli. 

Charax Gronow, Mus. Ichth., I, 1754, 10 (containing the modern Characinus 

gibbosus and Poecilurichthys bimaculatus) . — Scopoli, Intr. Hist. Nat., 1777, 455. 
Characinus Lacepede, Hist. Nat. Poiss., V, 1802, 269 (sp.). — Swainson, Class. 

Fishes, Amph., and Rept,, II, 1829, 289 (gibbosus).— Gill, Proc. U. S. Nat. 

Mus., XVIII, 1895, 213 (gibbosus). 
Epieyrtus Muller and Troschel, Horse Ichth., I, 1845, 17 (gibbosus). 
Anacyrtus Gunther, Catalogue, V, 1864, 345 (gibbosus and pauciradiatus) . 

Type, Salmo gibbosus Linnaeus. 

Premaxillary with a feeble canine at each end and a double row of teeth 
between; lower jaw with two feeble canines and a series of conical teeth; anal very 
long; lateral line complete; fins naked; breast flat, bordered by the blade-like 
lower edges of the clavicles, which end in a spine in front and behind. 

255. Charax gibbosus (Linnaeus). (Plate LX, fig. 3.) 
" Charax 53," Gronow, Mus. Ichth., I, 1754, 19, pi. 1, fig. 4; Zoophyl., 1763, 124, 

No. 380. 
Salmo gibbosus Linnaeus, Syst, Nat,, ed. 10, I, 1758, 311, No. 19; ed. 12, I, 1766, 

513 (Surinam). — Bloch and Schneider, Syst. Ichth., 1801, 419. 
Epieyrtus gibbosus Muller and Troschel, Horse Ichth., I, 1845, 17, pi. 2, fig. 1; 

in Schomburgk, Reisen, III, 1848, 635 (Lower Essequibo). 
Cynopotamus gibbosus Cuvier and Valenciennes, Hist, Nat. Poiss., XXII, 1848, 

321, pi. 645 (Mana; Essequibo; Amazon). — Castelnau, Anim. Am. Sud, 

Poiss., 1855, 75 (Amazon; Ucayale). — Garman, Bull. Essex Inst., XXII, 1890, 

11 (Coary; Cudajas; lea; Javary; Jutahy; Lake Hyamary; Manacapurii; 

Manaos; Obidos; Porto do Moz; Rio Negro; Silva, Lake Saraca; Surinam; 

Tabatinga). 
Anacyrtus gibbosus Gunther, Catalogue, V, 1864, 346 (Surinam; British Guiana). 

— Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 57. — 

Perugia, Ann. Mus. Genova, (2), X, viii, 1897, 26 (Rio Beni). 
Charax gibbosus Fowler, Proc. Acad. Nat, Sci. Phila., 1906, 453 (Surinam). — 

Eigenmann and Ogle, Proc. U. S. Nat, Mus., XXXIII, 1907, 32 (Guiana; 

Paraguay). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 

444. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 401 

Epicyrtus macrolepis Kner, "Familic der Characincn," ii, 1859, 39, pi. 6, fig. 1 

(Cujaba; Rio Paraguay; Irisanga). — Steindachner, "Fisch-fauna Magda- 

lenen-Stromes," 1878, 46. — Boulenger, Trans. Zool. Hoc. London, XIV, 1896, 

36 (Descalvados). 
Anacyrtus macrolepis Boulenger, Bull. Mus. Zool. ed Anat. Comp. Torino, 

XV, 1900, 948 (near Corumba). 
Characinus gibbosus Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903, 

525 (Arroyo Trementina). 

Very abundant in lowlands. 

Six hundred and thirty specimens, 35-135 mm. Botanic Garden. (C. M. Cat. 
No. 2124a-x; I. U. Cat. No. 12304.) 

Seventy-two specimens, 38-134 mm. Georgetown trenches. (C. M. Cat. 
No. 2125a-j; I. U. Cat, No. 12305.) 

Twenty specimens, 52-85 mm. Lama Stop-Off. (C. M. Cat. No. 2126a-e; 
I. U. Cat. No. 12306.) 

Ten specimens, 50-88 mm. Creek in Mora Passage. (C. M. Cat. No. 2127- 
a-e; I. U. Cat. No. 12307.) 

Six specimens, 60-103 mm. Issorora Rubber Plantation. (C. M. Cat. No. 
2128a-c; I. U. Cat, No. 12308.) 

Five specimens, 65-97 mm. Aruka River. (C. M. Cat. No. 2129a-c; I. U. 
Cat. No. 12309.) 

Eleven specimens, 65-137 mm. Wismar. (C. M. Cat, No. 2130a-/; I. U. 
Cat. No. 12310.) 

Twenty-nine specimens, 53-105 mm. Rockstone sand-bank. (C. M. Cat. 
No. 2131a-e; I. U. Cat. No. 12311.) 

Fifty-two specimens, the largest 1 15 mm. Crab Falls. (C. M. Cat. No. 2132- 
a-e; I. U. Cat. No. 12312.) 

One specimen, 72 mm. Tumatumari. (C. M. Cat. No. 2133.) 

Two specimens, 59-68 mm. Konawaruk. (C. M. Cat. No. 2134a; I. U. Cat. 
No. 12113.) 

Head 3.75-4; depth 2.6-3.75; D. 11; A. 48-56; 60 scales 16-53 to 60 6I -9; eye 
1 in snout, 3.66 in head, 1 in interorbital in the adult; .75, 3, and .75 respectively 
in specimens 60 mm. long. 

Compressed, elongate; breast flat, with a median series of scales; postventral 

60 Of eighteen specimens examined two have A. 48, one A. 49, one A. 50, five A. 51, three A. 52, one 
A. 53, three A. 54, one A. 55, and one A. 56. 

61 Of twenty-one specimens examined two have A. 53, one A. 54, two A. 55, two A. 56, four A. 57, three 
A. 5S, three A. 59, and four A. 60. 



402 MEMOIRS OF THE CARNEGIE MUSEUM 

area compressed; dorsal profile from dorsal to base of occipital process forming an 
arc of a circle whose center is near the origin of the anal; profile depressed over the 
eye, rising slightly forward, the lowest point in the profile nearly half an orbital 
diameter below the line joining the tip of the snout and the tip of the occipital 
process; mouth very oblique; maxillary extending to the end of the first suborbital; 
maxillary-premaxillary border two-thirds the length of the head ; cheek very deep ; 
a large part below the second suborbital naked; preopercle with a distinct angle. 

Gill-rakers 6 + 8, strong, the longest about two-thirds the length of the eye. 

Origin of dorsal a little nearer to tip of snout than to caudal, its height about 
3.5 in the length; caudal small, its lobes 4 in the length; origin of anal in advance 
of the vertical from the origin of the dorsal, nearer to the tip of the snout than to 
the base of the last anal ray, its margin very slightly concave; ventrals reaching 
considerably beyond origin of anal; pectorals to about the middle of the ventrals. 

Scales largest above the pectoral, becoming minute on the predorsal area; 
lateral line nearly straight; fins naked; no longitudinal stria*, scales with smooth 
edges. 

A vertical, irregular humeral spot over the seventh or eighth scale of the 
lateral line; a triangular caudal spot, frequently very obscure. 

256. Charax rupununi sp. nov. 

Type, 58 mm. Rupununi. (Carnegie Museum Catalog of Fishes No. 2135.) 

Cotypes, four specimens, 46-51 mm. Rupununi. (C. M. Cat. No. 2136a; 
I. U. Cat. No. 12814.) 

Head 3.8; depth 3; D. 11; A. 46-48; scales 10-42 to 44-7; eye .7 in snout, 
3 in head, .7 in interorbital. 

Very similar to C. gibbosus, but the scales much larger; subpectoral blade 
of the clavicle prominent, its posterior spine extending to below the base of the 
last pectoral ray, its anterior spine claw-like, rising above the edge of the blade, 
directed upward, outward, and forward (simply forward in gibbosus), outer surface 
of the blade concave. Predorsal line naked (?). 

A small black spot over the seventh scale of the lateral line; a deep-lying 
black vertical line at the base of the caudal rays, a black spot contiguous with it 
forward. Otherwise as in C. gibbosus. 

ASIPHONICHTHYS Cope. 

Type, Asiphonichthys stenopterus Cope. 

This genus has all the characters of typical Charax, except that the lateral line 
is developed on a few anterior pores only. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 403 

257. Asiphonichthys hemigrammus sp. now (Plate LX, fig. 4.) 

Type unique, 27 mm. Gluck Island. (Carnegie Museum Catalog of 
Fishes No. 2137.) 

A second specimen was collected by Dr. Ellis on Gluck Island. 

Head 3.5; depth 3; D. 10; A. 45; scales 10-48-7, five scales with pores; eye 
.75 in snout, 3 in head, .75 in interorbital. 

Compressed, snout pointed, profile depressed over the eyes; maxillary extend- 
ing to end of first suborbital; nearly the entire lower half of the cheeks naked; 
gill-rakers 5 + 8, those of the upper arch short, those of the lower large and long. 

Scales without longitudinal stria 3 , fins naked; scales reduced in size on the 
back in front of the dorsal. 

Anterior spine of the clavicle claw-like, directed upward and forward; the 
posterior spine scale-like; pectoral without developed rays; origin of dorsal very 
little nearer to tip of snout than to caudal, behind the vertical from the origin of 
the anal; ventrals reaching to the base of the eighth anal ray. 

A black spot above and behind the last pore of the lateral line; a spot on the 
end of the caudal peduncle. 

In the two specimens mentioned above the pectoral is without developed rays. 
In a third specimen, probably belonging to this species (38 mm.), the pectorals are 
normally developed. 

Cynopotamus Cuvier and Valenciennes. 
Cynopotamus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 317. 
Cyrtocharax Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 454. 

Type, Hydrocyon argenteus Valenciennes. 

Teeth of lower jaw in a single series, consisting of four canines in front (of 
which the third is largest) and numerous small teeth on the sides; premaxillary 
teeth in two series, a canine at each end; maxillary without canines. Lateral 
line complete, scales very small. No opercular spine. Clavicle slightly notched, 
the lower edge not blade-like, without spines. 

I have examined the type of Cynopotamus argenteus (22 jagn. long, Buenos 

Aires) in the Jardin des Plantes. I was unable to find an inner series of teeth in 

the lower jaw. 

258. Cynopotamus essequibensis sp. nov. 

Type, one specimen, 175 mm. Potaro Landing. (C. M. Cat. No. 2146.) 

Cotype, one specimen, 180 mm. Tumatumari. (C. M. Cat. No. 2147.) 

Cotypes, seven specimens, 53-170 mm. Rockstone. (C. M. Cat. No. 2148- 

a-c; I. U. Cat. No. 12319.) 



404 MEMOIRS OF THE CARNEGIE MUSEUM 

Head 3.66-3.75; depth 3; D. 11; A. 42-47; scales 19-91 to 98-15; eye 1 in 
the snout, 3.33 in the head, 1 in the interorbital. 

Compressed, tail slender, predorsal region of the body heavy; predorsal profile 
arched to the occipital process, depressed over the eyes; preventral area rounded, 
with many small scales; postventral area broad but with a trenchant median keel; 
predorsal area rounded, entirely scaled. Fontanel reaching to above anterior 
margin of the pupil; mouth large, premaxillary-maxillary border without an angle, 
1.33-1.4 in the length of the head; maxillary extending far beyond the first sub- 
orbital ; second suborbital leaving a wide naked margin below. 

Maxillary with about sixty minute teeth, the uppermost ones largest, but no 
canines; premaxillary with an outer series of about ten teeth, of which the first 
and last are large canines, an inner series of two small canines opposite the fifth 
and seventh teeth of the outer series; each ramus of the lower jaw with four canines 
in front, of these the second is the smallest, the third much the largest, the first and 
fourth of about the same size, and about thirty graduated conical teeth on the sides. 

Gill-rakers 2 + 6, the middle one heavy, half as long as the eye. 

Scales largest about the origin of the lateral line, decreasing most rapidly to in 
front of the dorsal; about forty rows of scales in front of the dorsal; fins naked; 
lateral line almost straight ; surface of each scale with numerous denticles (as many 
as one hundred on the largest scales of one of the larger specimens) arranged in more 
or less regular series. 

Dorsal pointed, its origin in front of the middle, its height 4 in the length; 
caudal lobes short, 4.5 in the length; anal slightly emarginate in front, the origin 
and the middle of the dorsal equidistant from the snout, a little nearer to base of 
middle caudal rays than to tip of snout; ventrals reaching the anal in the young, 
falling short of it in the adult; pectoral reaching beyond origin of ventrals. 

A silvery lateral band; a dusky circular caudal spot at the end of the caudal 
peduncle; a large conspicuous triangular humeral spot, its base just above the 
fifth to the ninth scales of the lateral line, its apex on about the seventh row of 
scales above the lateral line. 

Acanthocharax 6 ' 2 gen. nov. 

Type, Acanthocharax microlepis sp. nov. 

Lateral line complete; origin of anal under the dorsal; scales moderate, 
cycloid; a strong spine on the angle of the preopercle, continuous with the margin 
of the lower limb; a small canine at the upper end of the maxillary, its margin with 

62 iKavda, a thorn; x<*P a s, name of the typical genus. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 405 

conical teeth to its tip; a strong canine at each end of the premaxillaiy, and two 
series of conical teeth between them; four graduated canines on the lower jaw in 
front, the last being much the largest, these followed on the sides by a series of 
about thirty graduated conical teeth; predorsal area naked. 

259. Acanthocharax microlepis sp. nov. (Plate LXI, fig. 1.) 

Type, 105 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 
2138.) 

Cotypes, forty-three specimens, 55-103 mm. Tumatumari. (C. M. Cat. 
No. 2139a-j; I. U. Cat. No. 12315.) 

Cotypes, three specimens, 48-85 mm. Crab Falls. (C. M. Cat. No. 2140- 
a-b; I. U. Cat. No. 12316.) 

Cotypes, twenty-two specimens, 51-82 mm. Rockstone. (C. M. Cat. No. 
214k/-e; I. U. Cat. No. 12317.) 

Head 3.4-3.66; depth 2.7-2.8; D. 11; A. 30-34; scales 9-47 to 53-6; eye .75 
in snout, 2.75 in head, .66 in interorbital. 

Compressed, head and shoulders heavy, profile depressed over the eye, arched 
from base of the occipital process to the dorsal; preventral area rounded; a deep 
notch in the clavicle for the reception of the pectoral, the process below the pectoral 
broad-tipped behind, no free spine in front; postventral area trenchant, a wide 
naked area below the second suborbital; mouth oblique, the maxillary extending 
beyond the first suborbital; distance from tip of snout to end of maxillary equal 
to distance from tip of snout to posterior margin of the eye; gill-rakers 5 + 9, 
the longest .4 of the eye. 

Scales very regularly imbricate, except on the breast, without longitudinal 
strise. A naked area beginning at the dorsal, widening forward and extending on 
either side of the occipital process; fins naked; lateral line decurved, complete. 

Origin of the dorsal nearer the snout than to the tail ; origin of anal and middle 
of dorsal nearly equidistant from the snout; anal distinctly emarginate; ventrals 
reaching anal, pectorals to near middle of ventrals. 

A humeral spot over the fourth to sixth scale of the lateral line; a large, diffuse 

caudal spot. 

Heterocharax gen. nov. 

Type, Heterocharax macrolepis sp. nov. 

Lateral line complete; origin of anal under the dorsal; scales moderate, 
cycloid; a spine on the lower angle of the preopcrcle; maxillary without a canine, 
the teeth graduated in both directions from the fifth; prcmaxillary with a single 



406 MEMOIRS OF THE CARNEGIE MUSEUM 

series of teeth ; several of those near the anterior end are canines, of which the third 
from the end is largest. Sides of lower jaw with minute teeth, a large conical tooth 
at the outer corner of the jaw, followed forward by four teeth decreasing in size, 
the median tooth again a large canine; predorsal area scaled. 

260. Heterocharax macrolepis sp. nov. (Plate LXI, fig. 2.) 

Type, 46 mm. to base of caudal. Rockstone. (Carnegie Museum Catalog 
of Fishes No. 2142.) 

Cotypes, three specimens, 38-42 mm. Rockstone. (C. M. Cat. No. 2143a; 
I. U. Cat. No. 12318.) 

Cotype, one specimen, 37 mm. Wismar. (C. M. Cat. No. 2144a.) 

Head 3.6-3.9; depth 2.75-3; D. 10 or 11; A. 37 or 38 (or 42 in the Wismar 
specimen) ; scales 6 or 7-37 to 40-5; eye .5 in snout, 2.3 in head, .5 in interorbital. 

Slender, profile without notable hump or depression ; occipital process extend- 
ing less than one-fourth the distance to the dorsal; prevcntral area flat, post- 
ventral area trenchant; maxillary not reaching to the end of the first suborbital; 
cheeks entirely covered by the second suborbital; distance from tip of snout to 
end of maxillary equal to distance from tip of snout to middle of eye. Gill-rakers 
7 + 12. 

Scales regularly imbricate, not notably decreased toward the predorsal area; 
a median series of about nine scales in front of the dorsal ; about two pairs of scales 
between the occipital process and the median series; scales with from two to seven 
radiating striae. Fins naked. 

Origin of dorsal equidistant from snout and caudal; highest dorsal ray 4 in 
the length; origin of anal a little farther from snout than origin of the dorsal; 
ventrals reaching anal; pectorals to the ventrals. 

Silvery, without distinct spots. A dark streak along the sides and along base 

of anal. 

Subfamily Acestrorh yn cm n m . 

Acestrorhynchus Eigenmann. 

Xiphorhynchus Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 76 (falcatus). 

Xiphorhamphus Muller and Troschel, Horse Ichth., I, 1845, 17 (falcatus). 

Acestrorhynchus Eigenmann, Smiths. Misc. Coll., Quarterly Issue, XLV, 1903, 146 

(falcatus). 

The name Xiphorhynch us is preoccupied by Swainson's genus of birds, proposed 
in 1827. Xiphorhamphus is preoccupied by Blyth's genus of birds in 1843. 

Type, Salmo falcatus Bloch. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 407 

Prcmaxillary horizontal, its teeth strictly conical, in a single series, the second 
(or first) tooth and the next to the last strong, sharp, canine; anterior upper part 
of maxillary little oblique, with teeth similar to those of the premaxillary, the first 
and fourth or fifth being canines; the posterior part of the maxillary abruptly much 
oblique, with the exception of the teeth entirely concealed by the first suborbital 
when the mouth is closed; back part of mandible with minute, recurved teeth, 
preceded by three widely spaced canines, the middle one largest. 

Pectorals not overlapping the far remote ventrals; scales cycloid; lateral line 
complete; tongue long and free. 

Key to the Guiana Species of Acestrorhynchus. 
a. A conspicuous vertical black humeral blotch; caudal spot small and circular, or larger and continued on 

the middle caudal rays. Lateral line 79-95; A. 25-29 falcatus. 

aa. Shoulder-girdle with a minute spot in front of the origin of the lateral line; anal long, with 2S-33 rays. 

Lateral line 93-1 14 microlepis. 

aaa. No shoulder-spot, opercle margined with dark; A. 23-26. Lateral line 144-152 falcirostris. 

aaaa. A black band from the tip of the snout to the caudal; A. 27; scales 79, eight between lateral hue and anal. 

nasutus. 

261. Acestrorhynchus falcatus (Bloch). (Plate LXI, fig. 3.) 
Salmo falcatus Bloch, Ausl. Fische, VIII, 1794, 120, pi. 385 (Surinam). 
Xiphorhynchus falcatus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

337, part (Surinam). — Castelnau, Anim. Am. Sud, Poiss., 1855, 75 (Amazon). 
Xiphorhamphus falcatus Muller and Troschel, Horse Ichth., I, 1845, 17; in 

Schomburgk, Reisen, III, 1848, 635 (Essequibo; Pomeroon). — Gunther, 

Catalogue, V, 1864, 354.— Vaillant, Bull. Mus. d'Hist. Nat., V, 1899, 154 

(Carsevenne) . 
Acestrorhynchus falcatus Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 

1907, 34 (Surinam). — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 447. 
Xiphorhamphus ferox Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 

(Essequibo); Catalogue, V, 1864, 355 (Essequibo). 

One specimen, 182 mm. Barima. (C. M. Cat. No. 1960.) 

One specimen, 270 mm. Lama Stop-Off. (C. M. Cat. No. 1995.) 

Nine specimens, 96-120 mm. Lama Stop-Off. (C. M. Cat. No. 1964a-c; 
I. U. Cat. No. 12232.) 

Two specimens, 102-111 mm. Malali. (C. M. Cat. No. 1965a; I. U. Cat. 
No. 12242.) 

Eleven specimens, 85-114 mm. Maduni Creek. (C. M. Cat. No. 1966a-c; 
I. U. Cat. No. 12233.) 



408 MEMOIRS OF THE CARNEGIE MUSEUM 

Three specimens, 96-119 mm. Amatuk. (C. M. Cat. No. 1967a; I. U. Cat, 
No. 12234.) 

One specimen, 152 mm. Tukeit. (C. M. Cat. No. 1968a.) 
Two specimens, 110-122 mm. Christianburg. (C. M. Cat. No. 1969a; I. U. 
Cat. No. 12235.) 

One specimen, 85 mm. Erukin. (C, M. Cat. No. 2456.) 
One specimen, 133 mm. Konawaruk. (C. M. Cat. No. 1970a.) 
One specimen, 136 mm. Wismar. (C. M. Cat. No. 1971a.) 
One specimen, 155 mm. to base of caudal. Potaro Landing. (C. M. Cat, 
No. 1972a.) 

Two specimens, 118-121 mm. Below Packeoo Falls. (C. M. Cat. No. 1973a; 
I. U. Cat. No. 12236.) 

One specimen, 132 mm. Gluck Island. (C. M. Cat, No. 1974a.) 
Head 3.5; depth 4.5-5; D. 11; A. 25 in two specimens, 26 in three, 27 in 
nine, 28 in six, 29 in two. Scales usually 87-89, but ranging from 79-95. 63 Eye 
4.8 in snout, 4-4.5 in head, 1.3-1.5 in interorbital. 

This species, very similar to A. microlepis, can readily be distinguished from 
the other species found in Guiana by the very large humeral blotch. The caudal 
spot is small, well-defined, and circular, confined to the base of the caudal rays in 
the specimens from Barima, Lama Stop-Off, and Maduni Creek, i. e., in those from 
the tidal area. In specimens from the interior the humeral spot increases in size, 
and the caudal spot also becomes larger and more diffuse, extending on the caudal 
peduncle and frequently to the end of the middle caudal rays. 

The specimens from Lama Stop-Off had the middle of the dorsal orange, two 
intense orange bands fading out backward on either side of the caudal spot, and a 
yellow band out from the caudal spot and around it; adipose yellowish. 

262. Acestrorhynchus microlepis (Schomburgk). 
Hydrocyon microlepis Schomburgk, Fishes Brit. Guiana, I, 1841, 247 (Rio Negro; 

Rio Branco; Essequibo). 
Xiphorhamphus microlepis Muller and Troschel, Horse Ichth., I, 1845, 18; in 

Schomburgk, Reisen, III, 1848, 636 (Cameroon; Upper Essequibo; Rupununi; 

Takutu). — Gunther, Catalogue, V, 1864, 355 (Essequibo; British Guiana).— 

Steindachner, "Flussfische Siidamerika's, " iv, 1882, 14 (Huallaga; Iquitos; 

Amazons). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 

58. 

63 All the specimens but one from Amatuk with fewer than 87 rays. The scales as far so examined are 
79 in one, SO in one, S2 in one, S3 in two, S7 in six, SS in five, 89 in four, 90 in two, 91 in one, 93 in one, and 
95 in one. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 409 

Acestrorhynchus microlepis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, 

III, 1910, 447. 

I have examined a specimen in the Berlin Museum and: 

Seventeen specimens, 86-222 mm. Crab Falls. (C. M. Cat. No. 1975a-e; 
I. U. Cat, No. 12223.) 

One specimen, 148 mm. Creek below Potaro Landing. (C. M. Cat. No. 
1976a.) 

Four specimens, 99-146 mm. Malali. (C. M. Cat. No. 1977a; I. U. Cat. 
No. 12336.) 

Six specimens, 106-107 mm. Botanic Gardens. (C. M. Cat. No. 1988a-c; 
I. U. Cat. No. 12224.) 

Five specimens, 90-156 mm. Maduni Creek. (C. M. Cat, No. 1979a-6; 
I. U. Cat. No. 12225.) 

Three specimens, 116-134 mm. Georgetown trenches. (C. M. Cat. No. 
1980a-fc; I. U. Cat. No. 12226.) 

Two specimens, 86-110 mm. Wismar. (C. M. Cat. No. 1981a; I. U. Cat. 
No. 12227.) 

One specimen, 47 mm. Erukin. (C. M. Cat. No. 1982a.) 

Ten specimens, 104-162 mm. Tumatumari. (C. M. Cat. No. 1983a-c; I. U. 
Cat, No. 12228.) 

Seventeen specimens, 74-168 mm. Rockstone sand-bank. (C. M. Cat. No. 
1984o-e; I. U. Cat. No. 12229.) 

Three specimens, 207-270 mm. Lama Stop-Off. (C. M. Cat. No. 1985a-6; 
I. U. Cat. No. 12230.) 

One specimen, 200 mm. Issorora Rubber Plantation. (C. M. Cat, No. 
1986a.) 

Five specimens, 85-242 mm. Konawaruk. (C. M. Cat. No. 1887a-d; I. U. 
Cat. No. 12231.) 

Head 3.4-3.8; depth 5-6.5; D. 11; A. 28-33, most frequently 32 or 33; 
scales 93-95 in specimens from the Georgetown trenches, 113-114 in those from 
Crab Falls, and 101-105 in those from Lama Stop-Off; eye 1.8 in the snout, 4.5 
in the head, 1.1 in the interorbital ; 1.7, 4, .7, respectively in the young. 

Readily distinguished by a small black spot on the shoulder-girdle in front of 
the origin of the lateral line; a circular caudal spot, Dorsal, upper caudal lobe, 
and adipose orange; lower caudal band yellow in the specimens from Maduni. 

Dr. Ellis took one specimen in brackish water at Georgetown. 



410 MEMOIRS OF THE CARNEGIE MUSEUM 

263. Acestrorhynchus falcirostris (Cuvier). 

Hydrocyon falcirostris Cuvier, Mem. Mus. d'Hist, Nat., V, 1819, 361, pi. 27, fig. 3. 

Xiphorhynchus falcirostris Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 76. 

Xiphorhamphus falcirostris Muller and Troschel, Horse Ichth., I, 1845, 18 — 
Kner, "Familie der Characinen," ii, 1859, 50 (Matto Grosso). — Gunther, 
Catalogue, V, 1864, 354 (Demerara; River Cupai); Proc. Zool. Soc. London, 
1868, 247 (Xeberos; Pebas).— Cope, Proc. Am. Philos. Soc, XVII, 1878, 
688 (Peruvian Amazon). — Steindachner, "Flussfische Siidamerika's," iv, 
1882, 15 (Huallaga). — Eigenmann and Eigenmann, Proc. U. S. Nat. Mus., 
XIV, 1891, 58. 

Acestrorhynchus falcirostris Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 462.— 
Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907, 35.— Eigen- 
mann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 447. 

Hydrocyon armatus Schomburgk, Fishes Brit. Guiana, I, 1841, pi. 25, not descr. 
One specimen, 140 mm. Malali. (C. M. Cat. No. 1909a.) 
Four specimens, 157-357 mm. Malali. (C. M. Cat. No. 1996a-o; I. U. 

Cat. No. 12337.) 

Two specimens, about 170 mm. Twoca Pan. (C. M. Cat. No. 1978a; 

I. U. Cat. No. 12237.) 

Two specimens, 335-342 mm. Maduni Creek. (C. M. Cat. No. 1990a; 

I. U. Cat. No. 12238.) 

One specimen, 205 mm. Wismar. (C. M. Cat. No. 1991a.) 

Twelve specimens, 150-340 mm. Rockstone. (C. M. Cat. No. 1992a-c; 

I. U. Cat, No. 12239.) 

Two specimens, 270-315 mm. Lama Stop-Off. (C. M. Cat. No. 1993a; 

I. U. Cat. No. 12240.) 

Two specimens, 237-238 mm. Konawaruk. (C. M. Cat. No. 1994a; I. U. 

Cat. No. 12241.) 

Head 3.33-3.6; depth 6-7; D. 11; A. 22-26; lateral line 144-152, sixteen 

scales between lateral line and origin of anal. Eye 2-2.25 in the snout, 5-5.5 

in the head, 1-1.5 in the intcrorbital. 

Fontanel not extending forward to middle of eye. 

No shoulder-spot; a small, circular, well-defined, intense black caudal spot; 

upper part of opercle blackish; pectoral and caudal yellowish in life, the middle 

caudal rays red to orange. 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 411 

264. Acestrorhynchus nasutus sp. now (Plato LXI, fig. 4.) 

Type unique, 79 mm. Rockstone. (Carnegie Museum Catalog of Fishes 
No. 1959.) 

Distinguished by its long soft-tipped snout, short frontal fontanel, lateral 
bands, long head, etc. 

Head 3.1; depth 6; D. 11; A. 27; scales 79, eight between lateral line and 
anal; eye 2.33 in the snout, 3.7 in the head, .7 in the interorbital. 

Frontal fontanel very short, not reaching forward to above middle of eye; 
tip of snout soft. 

A dark stripe from the tip of the snout to the end of the middle caudal rays; 

no humeral spot; a distinct enlargement of the band into a caudal spot; a second 

dark band from the end of the anal forward to above the space between the anal 

and ventrals. 

Subfamily Hydrocynin^e. 

Hydrocynus Cuvier. 

H ydrocynus Cuvier, Regne Animal, II, 1817, 167. 

Xiphostoma Spix, Selecta Gen. et Spec. Pise. Bras., 1829, 78, pi. 42. 

Type, Hydrocynus lucius Cuvier. 

Lepidosteus-like Characins, the snout prolonged into a beak; each jaw with 
a series of minute conical teeth; dorsal in posterior half of the body; scales dentic- 
ulate on the margin; lateral line complete. 

One of the four species of the genus is locally abundant in Guiana. 

265. Hydrocynus cuvieri (Agassiz). 

Xiphostoma cuvieri Agassiz, Selecta Gen. et Spec. Pise. Bras., 1829, 78, pi. 42.— 
MtlLLER and Troschel, Horse Ichth., I, 1845, 20, pi. 3, fig. 3 (Brazil and Gui- 
ana). — Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 355 (Ama- 
zon). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 636 (Upper 
Essequibo, Takutu; Rupununi). — Kner, "Familie der Characinen," ii, 1859, 
pi. 8, fig. 17 (Marabitanos).— Gunther, Catalogue, V, 1864, 357— Eigen- 
mann and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 59.— Pellegrin, 
Bull. Mus. d'Hist, Nat,, V, 1899, 157 (Apure). — Eigenmann, Repts. Princeton 
Univ. Exp. Patagonia, III, 1910, 446. 

Xiphostoma ocellatum Schomburgk, Fishes Brit. Guiana, I, 1841, 245, pi. 18 
(Essequibo; Rios Negro and Branco). 

Xiphostoma oseryi Castelnau, Anim. Am. Sud, Poiss., 1855, 76, pi. 40, fig. 1 
(Tocantins). 



412 MEMOIRS OF THE CARNEGIE MUSEUM 

I have examined the specimen figured by M uller and Troschel and: 

Twenty-eight specimens, 120-200 mm., and one about 340 mm. Rockstone 
sand-bank. (C. M. Cat. Nos. 1115a and 1996a-g; I. U. Cat. No. 12244.) 

One specimen, 500 mm. Rupununi. (C. M. Cat. No. 2464.) 

Head 2.8-3.42; depth 6.5-7.5; D. 10; A. 10 or 11; V. 9; P. 30; scales 12-100 
to 108-8; eye 4.3-5 in snout, 8-8.5 in head, 1.5-1.75 in interorbital. 

Elongate, snout and lower jaw greatly prolonged into a slender pointed beak; 
upper jaw ending in a fleshy or cartilaginous tip more than half as long as the eye. 
Profile from dorsal to tip of snout nearly straight and horizontal; pafietals with a 
zigzag suture; no fontanel; snout considerably more than half the length of the 
head; teeth minute, very numerous, in a single series in each jaw. Maxillary 
meeting the premaxillary at a distinct angle, ankylosed with it; cheeks with a very 
narrow naked border below the suborbitals in the young, entirely covered in the 
old; gill-rakers about twelve on the lower arch, very small, the anterior ones reduced 
to imbedded tubercles. 

Dorsal nearer to ventrals than to anal, narrowly rounded or obliquely truncate; 
caudal forked, the lobes not more than twice the length of the middle rays, some- 
times shorter; anal emarginate in the adult, the anterior rays reaching tip of last 
ray, the last three or four rays prolonged, the third from the last sometimes reaching 
the caudal; ventrals small, truncate or emarginate, reaching about half-way to 
anal; pectorals very broad, the inner rays minute, the outer 2.2-2.5 in the distance 
to the ventrals. 

Lateral line nearly straight, not continued on the basal scales of the caudal; 
scales regularly imbricate, with numerous irregular striae and denticulate margins 
in the adult. Fins naked. 

A lateral band in the young, narrow and distinct from the eye to the opercle, 
broader and less regular on the sides; back irregularly spotted; outer margins of 
upper and lower caudal lobe, and anterior margin of anal light, the rest of the fins 
blackish; dorsal, ventrals, and pectorals hyaline; a small black ocellus at the base 
of the middle caudal rays. These markings, with the exception of the caudal 
ocellus, are less distinct in the adult. 

Subfamily Erythriniinle. 
Hoplias Gill. 
Macrodon Muller and Troschel, Horse Ichth., Ill, 1842, 6. 
Hoplias Gill, Proc. U. S. Nat. Mus., XXVI, 1903, 1015. 
Type, Esox malabaricus Bloch. 



eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 413 

The name Macrodon is preoccupied. 

Caudal rounded; no occipital process; no fontanel; no adipose; mouth large; 
cheeks entirely covered by the suborbitals; teeth all conical; maxillary with a 
canine and numerous small teeth; premaxillary with a large canine near the sym- 
physis, a smaller one toward the sides, and numerous conical teeth; palatines with 
patches of teeth, the outer series enlarged; a detached patch of teeth in front of 
the palatines; mouth large, maxillary extending beyond the orbit; walls of the 
air-bladder normal. Supratemporal plate single. 

266. Hoplias macrophthalmus (Pellegrin). (Plate LXII, fig. 1.) 

"Aimara." 
Erythrinus macrodon (not of Agassiz) Schomburgk, Fishes Brit. Guiana, I, 1841, 

41 (all rivers). 
Macrodon malabaricus macrophthalmus Pellegrin, Bull. Mus. d'Hist. Nat., XIII, 

1907, 26 (Cayenne). 
Macrodon trahira (not of Spix) Muller and Troschel, in Schomburgk, Reisen, III, 

1848, 632 (all streams, especially near cascades). 
Hoplias 'malabaricus microphthalmus Eigenmann, Repts. Princeton Univ. Exp. 

Patagonia, III, 1910, 448. 

Six specimens, 85-410 mm. Wismar. (C. M. Cat. No. 2173a-c; I. U. Cat. 
No. 12338a-c.) 

One specimen, 191 mm. Creek below Potaro Landing. (C. M. Cat. No. 
2174a.) 

Two specimens, 401-460 mm. Maripicru Creek. (C. M. Cat, No. 2175a; 
I. U. Cat, No. 12339.) 

A head, 114 mm. long. Tumatumari. (I. U. Cat, No. 12340.) 

A head, 152 mm. long. Creek above Rockstone. (C, M. Cat. No. 2176.) 

Three specimens, 94, 95, and 260 mm. Tukeit. (C. M. Cat, Nos. 2177a and 
2230a; I. U. Cat, No. 12341.) 

Three specimens, 85-87 mm. Malali. (C. M. Cat. No. 2178a-6; I. U. Cat. 
No. 12342.) 

There is also a specimen in the Berlin Museum collected by Kappler in Surinam. 

The specimen represented by the head from Rockstone was about 500 mm. 
long. I was told that specimens twice as large are taken in the creeks (which are 
really good-sized rivers) emptying into the Essequibo River above Rockstone. 
Schomburgk says they reach a size of four feet. No specimens were taken nearer 
the coast than Rockstone and Wismar. It is one of the most highly esteemed of 
the fishes. 



414 MEMOIRS OF THE CARNEGIE MUSEUM 

Eye 6.5 in the head in a specimen about 500 mm., 5 in specimens 300-400 mm., 
4 in specimens 50-250 mm.; 2 in the interorbital in the largest, 1.4 in specimens 
300-400 mm.; .6 in specimens 50-150 mm. 

Head 3-3.25 in the length measured to the end of the last scale on the caudal; 
depth 4-4.3; D. 15, rarely 16; A. 10; scales 43-45; thirteen, rarely fourteen, 
scales from lateral line to lateral line across the back in front of the dorsal. 

Elongate, subcylindrical, the head pointed; mouth large, the lips meeting so 
as to obscure their sinuate margin; maxillary-premaxillary border about half the 
length of the head, the maxillary slipping under the prolonged first suborbital; 
cheeks entirely covered by the first suborbital, which is continued back to the 
vertical limb of the preopercle, and the second and third suborbitals above it; 
origin of dorsal 1.5 orbital diameters nearer to the snout than to the base of the 
middle caudal rays, its margin broadly rounded, the highest rays a little over half 
the length of the head, its base one-half its distance from the end of the lateral line; 
caudal equal to the length of the head less the opercle; anal pointed, scarcely 
reaching the caudal; ventrals rounded, inserted a little in advance of the middle 
of the dorsal, shorter than the caudal, equal to the pectorals. 

Scales cycloid, regularly imbricate, nowhere specially increased or decreased 
in size; fins naked; lateral line straight, axillary scale very small. Tubes of the 
lateral line well-developed, multiple in the larger specimens. 

Lower jaw mottled; a dark bar from the eye to the angle of the preopercle, 
another running straight back, expanding on the opercle; frequently a spot in the 
membrane behind the tip of the subopercle. Four horizontally V-shaped cross- 
bars, the widest down from the front part and from in front of the dorsal; the 
second and third from spots on the back behind the dorsal and the last from the 
base of the upper caudal rays; dorsal with five rows of spots or with five broad 
dark bands; caudal similar; anal and upper surface of ventrals and pectorals each 
with four or five bars and some spots. 

267. Hoplias malabaricus Bloch. (Plate LXII, fig. 2.) 

"Tareira" Marcgrave, Hist. Rer. Nat. Bras., IV, 1648, 157. 

Esox malabaricus Bloch, Ausl. Fische, VIII, 1794, 149, pi. 392. 

Synodus malabaricus Bloch and Schneider, Syst. Ichth., 1801, 397. 

Macrodon malabaricus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 
II, 1889, 102 (Para; Gurupa; Villa Bella; Avary; Montalegre; Arary; Porto 
do Moz; Obidos; Lago Alexo; Tonantins; Manaos; Tapajos; Santarem; 
Cudajas; Hyanuary; Manacapurii; Rio Negro; Silva, Lake Saraca; Teffe; 



EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 415 

Hyavary; Rio Negro, near Lago Alexo; Itabapuana; Tabatinga; Jutahy; 
Lago Maximo; lea; Tajapuni; Manes; Jatuarana; Lago Iuparana; Serpa; 
Campos; Barra de Pirahy; Rio Parahyba; Paraguay; Ueranduba; Surinam; 
Rio das Velhas; Rio San Francisco; Bon Jardin, Rio San Francisco; Rio 
Doce; Bahia; Santa Cruz; Santa Clara; Rio Mucury; Sao Matheos; Rio 
San Antonio; Rio Janeiro; Goyaz; San Goncallo; Jequitinhonha; Rio Puty; 
Buenos Ayres; Rio Grande; Porto Alegre; Rio Arassuahy, Minas Geraes; 
Muriahe; Guiana; Rio Ipojuco, Province Pernambuco). — Eigenmann, Ann. 
N. Y. Acad. Sci., VII, 1894, 633 (Rio Grande do Sul).— Lahille, Rev. Mus. 
la Plata, VI, 1895, 7 (Arroyo del Gato; Arroyo de Dona Flora; Dock Central). 
-Vaillant, Bull. Mus. d'Hist. Nat., Ill, 1897, 221 (Chagres); V, 1899, 154 
(Carsevenne; Carnot). — Eigenmann and Norris, Rev. Mus. Paulista, IV, 
1900, 355 (Rio Tiete).— Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 157 
( Apure) . 

Hoplias malabaricus Eigenmann and Kennedy, Proc. Acad. Nat. Sci. Phila., 1903 
508 (Rio Branco; Arroyo Trementina; Arroyo Chogolalina; Estancia La 
Armonia, Arroyo Carrumbez). — Evermann and Kendall, Proc. U. S. Nat. 
Mus., XXXI, 1906, 78.— Fowler, Proc. Acad. Nat, Sci. Phila., 1906, 293 
(Ambyiacu, Peruvian Amazon; Rio Grande do Sul; Bahia; Rio das Velhas; 
Surinam).— Eigenmann and Ogle, Proc. U. S. Nat. Mus., XXXIII, 1907, 36 
(Brazil; Trinidad; Truando;