XI E> RAR.Y OF THL UNIVERSITY Of ILLINOIS JATURAL HISTORY SURVE 530.5 v.10 cop.3 THE FISHES OF THE FRESH WATERS OF PANAMA. BY SETH E. MEEK* AND SAMUEL F. HILDEBRAND. PREFACE. The present report is based upon the fresh water species of fishes collected during the "Smithsonian Biological Survey of the Panama Canal Zone." The ichthyological reconnaissance, however, was made co-operatively by the Smithsonian Institution, Field Museum of Natural History and the U. S. Bureau of Fisheries. With the exception of a small number of specimens contributed by Messrs. H. Pittier and E. A. Goldman of the U. S. Department of Agriculture, the collections were made by the authors during two seasons, viz.; from January to May inclusive, 1911, and from January to March inclusive, 1912. The winter and early spring months were chosen because they represent the dry season in Panama. In 1911 the work was, however, well extended into the rainy season, for during the month of May it rained every day and the streams became so high and muddy that our efforts had to be confined to collecting marine species. It became impossible to dry the nets or our clothing, except by artificial heat, therefore, on May 22 the work was abandoned and resumed the following January. We are greatly indebted to the Panama Rail Road Company for furnishing free transportation to and from New York and for a free pass on the Panama Rail Road. We are also deeply indebted to the Isthmian Canal Commission, and General George W. Goethals in particular, for extending to us every convenience and assistance pos- sible. To the Darien Gold Mining Company we also owe our deepest gratitude for rendering invaluable aid on our expedition to the Darien region. Without the help thus received it would have been impossible to make so large and thorough a collection as the present one. Our knowledge of the fresh water fishes of the Isthmus of Panama heretofore was fragmentary. It was based on small collections made at various times, usually not by naturalists, but by tourists and others who possessed a popular interest in the subject. The small collections thus secured were reported upon by various authors, viz.; Kner & Steindachner, Steindachner, Gunther, Gill, Evermann & Goldsborough * Deceased July 6, 1914. 217 2i8 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. and others. The collection at hand, therefore, is the first large and general one made in the fresh waters of the Isthmus. The present survey was made after much work had been done on the Canal and natural conditions had been considerably disturbed, but yet before the water was turned into the Canal and before the species from the two slopes were allowed to intermingle. The natural conditions had at the time of our visits been most disturbed in the Rio Grande on the Pacific slope of the Canal Zone. This stream had been thoroughly cut to pieces and in view of this fact it seemed important, in order to obtain a comprehensive knowledge of the fishes of the Canal Zone, to extend the survey to other Pacific slope streams. In this connection it is an interesting fact that several species, namely, Pimelodella chagresi, Plecostomus plecostomus, Astyanax fasciatus, Brycon argenteus, Curimatus magdalena, Thoracocharax maculatus, Priapichthys tridentiger and Microeleotris panamensis gen. et sp. nov., taken in streams both east and west of the Rio Grande were not found in it, the presumption being that they once occurred there but that they had disappeared on account of the unfavorable conditions created by the construction of Canal. Two small preliminary papers containing the descriptions of new species have already been published in the Zoological Series of Field Museum of Natural History (Vol. X, 1912 and 1913, pp. 67 and 68, and pp. 77 to 91). In the present and final report we have endeavored to give concise descriptions of all the species known to occur in the fresh waters of Panama, along with keys which we believe will afford ready means of identification. We have avoided technical terms as far as possible and hope that the work may prove of use in the high schools of the Canal Zone, and in other institutions of learning in Panama, as well as to ichthyologists. A complete report on the marine species is in the course of preparation and will be offered later. The senior author, on account of ill health, was obliged to with- draw from the work during the course of its preparation. His untimely death occurred on July 6, 1914, thus delaying greatly the completion of the report. In the fall of 1915 Prof. C. H. Eigenmann of Indiana University kindly offered the use of his library, collections from Colom- bia and other South American countries, and his laboratory at the University for the further study of this collection. Advantage was taken of this opportunity, the specimens were shipped to Bloomington, and the study of them was there completed by the junior author, who is much indebted to Prof. Eigenmann for many valuable suggestions and for aid in classifying difficult forms. Without the Colombian collection for comparison, many forms, the relationship of which is now definitely established, would have remained unknown. LIST OF ILLUSTRATIONS. PLATES. VI. (i) Native pulling a boat across rapids on the Upper Chagres. (2) Fishing party on the Rio Gatun. VII. (i) Natives "poling" a boat across rapids on the Upper Chagres. (2) Fishing party on a trail through the jungle. VIII. (i) An Indian family of the Rio Tuyra Basin. The late Dr. S. E. Meek in rear. (2) Scene on the Upper Chagres. IX. Trachycorystes amblops (Meek & Hildebrand). X. Lasiancistrus planiceps (Meek & Hildebrand). XI. Leptoancistrus canensis (Meek & Hildebrand), type of a new genus. XII. Loricaria capetensis Meek & Hildebrand, ventral view of anterior part of fish. XIII. Oxyloricaria citurensis Meek & Hildebrand, ventral view. XIV. Hoplosternum punctatum sp. nov., side view. XV. Hoplosternum punctatum sp. nov., ventral view. XVI. Cyclopium pirrense Meek & Hildebrand. XVII. Apareiodon dariensis (Meek & Hildebrand). XVIII. Pseudocheirodon affinis gen. et sp. nov., male. XIX. Bryconamericus cascajalensis sp. nov., male. XX. Hemibrycon dariensis sp. nov. XXI. Creagrutus notropoides Meek & Hildebrand. XXII. Rceboides guatemalensis (Gunther). XXIII. Roeboides occidental's sp. nov. XXIV. Brycon petrosus Meek & Hildebrand. XXV. Brycon argenteus Meek & Hildebrand. XXVI. Sternopygus dariensis sp. nov. XXVII. Sternarchus rostratus Meek & Hildebrand. XXVIII. Cichlasoma tuyrense Meek & Hildebrand. XXIX. Cichlasoma calobrense Meek & Hildebrand. XXX. Cichlasoma umbriferum Meek & Hildebrand. XXXI. Neetroplus panamensis Meek & Hildebrand. XXXII. Hemieleotris latifasciatus (Meek & Hildebrand), type of a new genus. 219 220 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. X. TEXT FIGURES. 1. Diagram showing the peculiar scaling at base of caudal fin of the male of Compsura gorgonce (Evermann & Goldsborough). 2. Front teeth of Compsura gorgona (Evermann & Goldsborough). (After Evermann & Goldsborough.) 3. Front teeth of Pseudocheirodon affinis gen. et sp. nov. (After Cheirodon insignis [non Steindachner] Evermann & Goldsborough.) 4. Distal part of intromittent organ of Gambusia nicaraguensis Gunther. (Greatly magnified.) 5. Distal part of intromittent organ of Gambusia episcopi Stein- dachner. (Greatly magnified.) 6. Distal part of intromittent organ of Priapichthys tridentiger (Gar- man). (Greatly magnified.) 7. Distal part of intromittent organ of Priapichthys dariensis (Meek & Hildebrand). (Greatly magnified.) 8. Distal part of intromittent organ of Priapichthys panamensis sp. nov. (Greatly magnified.) 9 . Distal part of intromittent organ of Pasciliopsis elongatus (Gunther) . (Greatly magnified.) 10. Distal part of intromittent organ of Mollienisia sphenops (Cuvier & Valenciennes). (Greatly magnified.) LIST OF GENERA AND SPECIES WHICH APPEAR AS NEW IN THE PRESENT PAPER. NEW GENERA. PACK Leptoancistrus 254 Pseudocheirodon 275 Leptophilypnus 361 Microeleotris 362 Hemieleotris 364 NEW SPECIES. Ancistrus spinosus 252 Hoplosternum punctatum 264 Pseudocheirodon affinis 275 Gephyrocharax intermedius 278 Bryconamericus cascajalensis 284 Hemibrycon dariensis 285 Rceboides occidentalis . . . . , 293 Sternopygus dariensis 309 Priapichthys panamensis 322 Eleotris isthmensis 359 Leptophilypnus fluviatilis 361 Microeleotris panamensis 363 Microeleotris mindii 364 221 INTRODUCTION. GENERAL TOPOGRAPHY AND HYDROGRAPHY OF PANAMA. In the region of the Canal Zone the Atlantic slope is very much broader than the Pacific slope. Following the line of the Panama Canal, it is about 40 miles from the Atlantic coast to the crest of the divide and only 10 miles from thence to the Pacific coast. This, in the Canal Zone region, where the rainfall is heavy,* gives rise to the comparatively large Rio Chagres on the Atlantic slope opposed by rather small coastal streams on the Pacific slope, namely, the Rio Chor- rera, Rio Grande, Rio Marte Arnade, Rio Abaco, Rio Juan Diaz and other small streams. Going eastward or toward Colombia the Pacific slope becomes broader and the Atlantic slope narrower. The increased width of the Pacific slope then gives rise to the rather large Rio Bayano, the mouth of which is about 30 miles east of Panama City, and to the still larger Rio Tuyra which empties into San Miguel Bay, about 100 miles south- east of Panama City. Opposite these streams, on the narrow Atlantic slope, there are only very small coastal streams. In western Panama the watershed more nearly follows the median line of the Isthmus and no large streams occur on either slope. There are then three river basins of considerable size in Panama, viz.; the Rio Chagres on the Atlantic slope and the Rio Bayano and the Rio Tuyra on the Pacific slope. Collections were made in all of these streams. The Rio Chagres with its numerous tributaries was quite thoroughly explored, and it is believed that our collections contain, with perhaps very few exceptions, all the species occurring there. Our explorations in the Rio Bayano and the Rio Tuyra basins were not so thorough, and our collections from these rivers are certainly not ex- haustive, but sufficient to indicate the nature of their faunas. Besides these large streams, the small streams opposite the Rio Chagres and as far westward as the Rio Chame on the Pacific slope were visited and collections made in each. On the Atlantic slope only a few of the small coastal streams, two at Porto Bello and two at Toro Point, were visited. This then leaves many small streams of western Panama unexplored. "The rainfall in the Canal Zone region is heaviest on the Atlantic slope and particularly at Porto Bello where during a single day of 24 hours as much as n inches of water are known to have fallen. In 1909, 58.07 inches of rain fell during the month of December and the total rainfall for the year was 237.28 inches. 223 224 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. That the faunas of these small streams are of much interest is indicated by the fact that Hoplosternum punctatum sp. nov. belonging to a dis- tinctly South American family, of which heretofore no representative was known north of the Rio Atrato Basin in Colombia, was taken in the Rio Marte Arnade, a small stream, about 6 miles east of Panama City, and was not seen elsewhere in Panama. Gephyrocharax inter- medius sp. nov. was found only in the Rio Chame; Bryconamericus cascajalensis sp. nov. only in the Rio Cascajal at Porto Bello; Rivulus brunneus Meek & Hildebrand only in a small coastal stream at Toro Point and Microeleotris panamensis gen. et sp. nov. only in the Rio Juan Diaz and the Rio Chorrera. Ancistrus chagresi, which is com- mon in the Rio Chagres Basin, was taken on the Pacific slope only in the Rio Chorrera. THE Rio CHAGRES AND ITS FAUNA. The Rio Chagres is but slightly affected by tides at its mouth, as there is a difference of less than two feet between mean high and mean low water on the Atlantic coast of Panama. Ascending this stream, it is found to flow through a low swampy region in its lower course, or as far as Gatun. Here it receives its largest tributary, the Rio Trinidad, which is a sluggish stream winding its way for many miles southward through a low, dense jungle where mosquitoes abound in countless numbers. It reaches the mountains opposite the Rio Chorrera. In the upland regions it is free from rapids, but the current is swift. At Gatun the Rio Chagres receives another tributary of considerable size, namely, the Rio Gatun, which assumes an easterly course, and is a clean, clear stream, usually with sandy or pebbly bottom and without rapids or falls but with a strong current. Following again the course of the Rio Chagres from Gatun upward it assumes the general direction of the present Canal, i. e., southeast- ward until Gamboa is reached where it makes a rather sharp turn to the left and then follows an east by northeast course. As far up as Alha- juela or about 50 miles from its mouth, following the winding course of the stream, the current is swift but no rapids occur. From this point upward it becomes swifter and at intervals rapids appear which can be crossed only when the water is at a low stage. At San Juan, the last native village on the river, the stream forks; the left fork is known as the Rio Pequeni which soon again divides forming the Rio Boqueron and the Rio Pequeni. The fork to the right, going up stream, at the village of San Juan is the Upper Chagres. Following its course the mouth of a large tributary is soon reached. This is the Rio Indio which has a waterfall a short distance above its mouth; below it a large num- FIELD MUSEUM OF NATURAL HISTORY. PLATE VI, ZOOLOGY. NATIVE PULLING A BOAT ACROSS RAPIDS ON THE UPPER CHAGRES. FISHING PARTY ON THE Rio GATUN. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 225 ber of specimens of Joturus pichardi were obtained with a discharge of dynamite. The regions through which the upper courses of these streams flow are entirely uninhabited. A traveler in this region is obliged to provide himself with provisions, for nothing can be obtained except fish and game. Large fishes belonging to the genus Brycon are plentiful, and there is doubtless also an abundance of game, although no effort was made by us to obtain it. The region is densely wooded and no head- way can be made into the jungle without cutting a trail. Large croco- diles and caimens abound, and several species of monkeys may from time to time be seen leaping from tree to tree. On several occasions numbers of monkeys made early morning visits to our camps, chatter- ing profusely in the trees overhead, but upon the first movement or sound from the occupants of the camp the chattering ceased and a grand rush was made for the jungle. We made the trip up these streams in a wooden dug-out, "poled" by two natives. As it is impossible to paddle a canoe against the strong current in most places, the natives use a pole with an iron shoe at the base. One man stands in the stern of the boat to guide and to push and the other occupies the bow, walking forward, securing a hold and then running back as the boat is pushed along. Even during our expedition, when the streams were at a very low stage it was necessary for us to land and walk past several rapids while our boatmen by means of a rope pulled the boat across them. In coming down stream and crossing rapids considerable skill is required. Our boatmen were very careful either to go faster than the current or slower in order to retain control of the boat. It is then obvious that an expedition on the Upper Chagres and its tributaries should not be undertaken without skillful boatmen who are familiar with the streams. The waters of the lower Chagres are constantly turbid, but those of its upper tributaries were clear and cool at the time of our expedition. The beds of all of the upper tributaries are pebbly or rocky. Large boulders usually occur at the rapids, making traveling all the more difficult. The stages of the river often change rapidly owing to freshets in the mountains, the highest water usually occurring during November and December, at the close of the rainy season, and the lowest water during February and March. The rapidity with which the stream at times rises may be seen from the following figures obtained from the records kept by the Isthmian Canal Commission at its hydrographic station at Alhajuela: On December 26, 1909, the river had an elevation of 96.6 feet at 7 :oo A. M. ; at 7 :oo P. M. the elevation was 121 feet. On December 26, 226 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 1911, it rose from an elevation of 101.4 feet at 9:00 A. M. to no feet by 10:00 A. M. It is evident that at such times all boating on the river must cease. The fish fauna in the upper courses of the Chagres is rather rich in quantity but rather poor in variety. On the lower courses of the Chagres the larger fishes have become comparatively rare, owing in part at least to the illegal use of dynamite, but the number of species is greater than in the uninhabited region. The following is a list of species obtained by us in the Rio Chagres Basin: Family Silurida; Pimelodella chagresi, Rhamdia wagneri: Family Loricariidce; Plecostomus plecostomus, Chcetostomus fischeri, Ancistrus chagresi, Loricaria uracantha: Family Characida; Astyanax ruberrimus, Bryconamericus emperador, Brycon petrosus, Brycon chagrensis, Gephyro- charax atricaudata, Creagrutus notropoides, Hyphessobrycon panamensis, Pseudocheirodon affinis gen. et sp. nov., Compsura gorgonce, Rceboides guatemalensis, Piabucina panamensis, Hoplias microlepis: Family Gymnotida; Hypopomus brevirostris: Family Pceciliida; Gambusia cascajalensis, Gambusia episcopi, Gambusia nicaraguensis , Mollienisia sphenops, Priapichthys tridentiger, Rivulus ekgans: Family Mugilida; Agonostomus macracanthus, Agonostomus monticola, Joturus pichardi: Family Cichlidce; jEquidens ccerukopunctatus, Cichlasoma maculicauda, Neetropolus panamensis, Geophagus crassilabris: Family Gobiidce; Awaous taiasica, Dormitator maculatus, Leptophilypnus fiuviatilis gen. et sp. nov., Microeleotris mindii gen. et sp. nov., Eleotris isthmensis sp. nov., Eleotris pisonis, Guavina guavina, Philypnus dormitor, and Sicydium salvini. The representatives of the family SiluridoB occur on both slopes of Panama and southward and seem to be well established species that are not at the present time undergoing any rapid changes in different localities. Of the family Loricariida, Loricaria uracantha was taken only in the Rio Chagres* and does in fact have no very near relatives. Since the Isthmus of Panama is the northernmost limit of the range of this family and its center of distribution occurs somewhere in South America, this species may be regarded as one of the earliest migrants,! which appears to have changed remarkably under the new environment. Chcetostomus fischeri is really a Pacific slope fish in Panama, but it seems to have reached this region before the last gap between the Rio Chagres and the Pacific slope streams was closed. It has apparently not thrived *Loricaria uracantha is recorded from the Pacific slope of Panama, but it was not seen there by us. tin our discussion on distribution, Panama is regarded as a very remote center of distribution. See Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, p. 134. FIELD MUSEUM OF NATURAL HISTORY. PLATE VII, ZOOLOGY. NATIVES "POLING" A BOAT ACROSS RAPIDS ON THE UPPER CHAGRES. FISHING PARTY ON A TRAIL THROUGH THE JUNGLE. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 227 well in the Chagres, as it is very rare there, nor has it undergone any changes different from those of the Pacific slope. Ancistrus chagresi, by whatever route it may have reached the Rio Chagres, is now abun- dant there and may also be regarded as one of the early migrants. It was found on the Pacific slope only in the, small Rio Chorrera, the upper tributaries of which are opposite those of the Rio Trinidad. It, therefore, seems probable that this species crossed from one stream into the other before the gap between them became closed. The other representative of this family, Plecostomus plecostomus, is of wide dis- tribution and occurs on both slopes of Panama and southward. Among the characins evolution seems to be rather actively at work in a number of species. Brycon chagrensis, Brycon petrosus, Creagrutus notropoides and Rceboides guatemalensis all have closely related opposites or relatives on the Pacific slope, but the influence of the different environment during their period of separation has brought forth certain definite and marked changes. Hyphessobrycon panamensis alone of all the characins from the Rio Chagres has no near relative elsewhere in Panama. The genus, however, reappears in Colombia. The Panama representative was probably one of the early migrants reaching the Chagres before the last passage between this river and the Pacific streams was closed. If it actually reached the Atlantic slope by that route, then we are obliged to conclude that the species was unable to maintain itself on the Pacific slope and while it became extinct there it thrived on the Atlantic. The rest of the species of the Chara- cidcB known from the Chagres are common to both slopes of Panama. Of these Astyanax ruberrimus at least also occurs throughout Colombia, and Hoplias microlepis while replaced by H. malabaricus in the Rio Tuyra Basin and in Colombia, oddly enough again reappears on the western slope of Ecuador. The single representative of the family Gymnotidcs is of wide dis- tribution, and does not appear to be undergoing any rapid changes. The representatives of the family Pceciliidoe are common to both slopes, with the single exception of Gambusia nicaraguensis which can scarcely be regarded a fresh water form, as it seldom occurs above brackish water. Of the family Mugilidcs three species occur in the Rio Chagres. Two of them at least are common to both slopes of Panama and Central America as well as to the West Indies. Of the family Cichlida there are two species, Mquidens cceruleo- punctatus and Geophagus crassilabris ,that are of rather wide distribution and are found everywhere in the streams of Panama. Cichlasoma maculicauda is found only on the Atlantic slope of Panama and north- 228 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. ward to Guatemala. Neetroplus panamensis is known only from the Rio Chagres, although there are representatives of the genus in Costa Rica and other parts of Central America. The last two species may be regarded as migrants from Central America. The fresh and brackish water representatives of the family Gobiidce alone seem to have Panama as a center of distribution. They appear to have yielded to the different environment of the two slopes and only one species, Sicydium salvini, an upland form, is now common to both slopes. Aivaous taiasica, Dormitator maculatus, Microeleotris mindii sp. nov., Eleotris pisonis and Philypnus dormitor all have very near relatives on the Pacific slope, differing sufficiently so that usually they can be distinguished quite readily. THE Rio BAYANO AND ITS FAUNA. The Rio Bayano is a broad stream at its mouth and owing to the excessively high tides on the Pacific coast of Panama, varying from 20 to 30 feet between high and low water, the current changes twice daily for 30 or more miles up stream. Throughout this entire distance the river is broad and muddy, but the head of steam boat navigation is not far above the mouth of the Rio Mamoni which empties into the main stream about 20 miles from the sea. The lower course of the Bayano has large quiet bays where the crocodile is very abundant. There are places where on a sunny day an observer may stand in one position and count a hundred or more noses of these beasts projecting above the water. Many marine species of fishes run up and down the lower part of this stream with the tides. The Rio Mamoni has a much greater fall than the main stream and soon rises above tide level. It then becomes, at least during the dry season, a clear stream with a rocky or pebbly bottom. About 10 or 15 miles above its mouth is situated the town of Chepo which is one of the oldest and best known towns of Panama outside of the limits of the Canal Zone. During the dry season this stream is quite small at this village. It was so low during our visit that we were obliged, in order to reach Chepo, to leave our dug-out behind and travel overland the last 5 or 6 miles. In this region of savanas this was not difficult. We did not explore the stream beyond Chepo, although it extends for many miles back into the mountains, and very probably supports forms of fishes not obtained by us. Following again the course of the main stream for from 10 to 15 miles above the mouth of the Mamoni another tributary of considerable size is reached. This is the Rio Calobre which flows through a densely wooded and uninhabited region. The lower portion of this stream is DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 229 also subject to a flow of water in opposite directions for a few miles above its mouth. The water, however, is fresh, as the back water entering it is the fresh water from the main stream which is being held back by the onrush 3 (tyP6 Pimelodus maculatusLac6pkde=Silu- rus clorios Bloch). Pseudariodes Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 99 (type Pseudariodes clarias Bloch). Pseudorhamdia Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 101 (type Pseudorhamdia ntaculata Lace"pede=S*7wMs clarias Bloch). Body elongate, head covered with thin skin, granulose; occipital process reaching dorsal plate; humeral process broad; fontanel not continued beyond anterior margin of eyes; eye with a free orbital mar- gin; one pair of maxillary barbels; 2 pairs of mandibular barbels; caudal fin forked. 2. Pimelodus clarias punctatus (Meek & Hildebrand). Megalonema punctatum Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 77 (Rio Tuyra, Marrigante, Panama). Megalonema robustum Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 78 (Rio Tuyra, Marrigante, Panama). Head 3.9 to 4.1; depth 4.4 to 5.25; D. I, 6; A. n to 13. Body elongate, compressed; dorsal region elevated; head not much wider than deep, its width 1.34 to 1.6 in its length; snout not very broad, its length 2.04 to 2.25 in head; eye 4.7 to 6; interorbital 2.94 to 4; width of mouth a little less than length of snout; maxillary barbels reaching opposite anal or to base of caudal; occipital process rather wide, not fully united with the dorsal plate, its greatest width greater than eye, except in young of less than 150 mm. in length; teeth in villiform bands, none on palatines or vomer; gill-membranes free from the isthmus; humeral process rather narrow, pointed slightly upward; dorsal spine equal to or a little longer than head, a rudimentary spine at its base; 242 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. origin of dorsal slightly nearer adipose than tip of snout; adipose fin shorter than head, 4.8 to 5.5 in length of body; caudal fin deeply forked, the upper lobe the longer; anal fin without distinct spine, its origin behind origin of adipose; ventral fins inserted under posterior rays of dorsal; pectoral spine with hooks on both sides in young, becoming smootiier with age, i to 1.23 in head. Color bluish above, pale silvery below. Young with numerous round specks or spots on head and side, which become fewer with age and wholly disappear in specimens of 200 mm. and more in length. Fins unmarked. We have 8 specimens of this species, ranging in length from 142 to 300 mm. All are from the lower Rio Tuyra, some of them from below the head of tide water. This fish is probably not distinct from P. clarias (Bloch) of which there are at hand numerous specimens from the Rio Atrato and Rio Magdalena. However, we do not find the dark spots, so characteristic in the young from the Rio Tuyra, present in the specimens from the more southern streams. The occipital process apparently is also slightly wider in the Rio Tuyra specimens. Our specimens may, therefore, be considered a variety of P. clarias with dark spots present in all except the adults. Habitat: Rio Tuyra Basin. 3. Genus Pimelodella Eigenmann & Eigenmann. Pseudorhamdia (non Bleeker) Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXIV, 1876, 604 (type Pimelodus lateristriga Muller & Troschel). Pimelodella Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd. Ser., I, 1888, 131 (type Pimelodus cristatus Muller & Troschel). This genus differs from Pimelodus in having a narrower and more spine-like humeral process and the fontanel extends farther back, notably past anterior margin of eye. Only a single species is found in the waters of Panama. 3. Pimelodella chagresi (Steindachner). Pimelodus (Pseudorhamdia) chagresi Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXIV, 1876, 584 (Rio Chagres and its tributaries). Pimelodella chagresi Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd. Sen, I, 1888, 134 (RioObispo), and Occ. Pap. Cal. Ac. Sci., I, 1890, 1 60 (Rio Chagres and its tributaries). Head 3.8 to 4.7; depth 5.2 to 6.2; D. I, 6; A. n or 12. Body elongate, compressed, the dorsal region moderately elevated; head rather narrow; snout tapering, 2.3 to 2.7 in head; eye 3.85 to 4.6; DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 243 interorbital 4.13 to 4.73; mouth narrower than length of snout; upper jaw a little in advance of the lower; maxillary barbels usually reaching to or somewhat past origin of anal; teeth in villiform bands, none on vomer or palatines; occipital process long and narrow, reaching dorsal plate; fontanel long and narrow, reaching backward to or a little beyond posterior margin of pupil; origin of dorsal about midway between tip of snout and origin of adipose; dorsal spine a little longer than eye and snout; adipose fin varying in length, but always longer than head, 3 to 3.95 in length of body; caudal fin deeply forked, the upper lobe much the longer, notably longer than head; anal fin without a spine, its origin a little behind origin of adipose; ventral fins failing to reach origin of anal, inserted just behind vertical from base of last dorsal ray; pectoral fins rather short, the spine without hooks on its distal third or fourth, but with strong hooks on basal portion, its length 1.2 to 1.63 in head. Color greenish, with a jet black lateral band and another pair of bands on each side of median line of back, extending from nape to upper surface of caudal peduncle. Fins unmarked. This species is represented by numerous specimens, ranging in length from 40 to 142 mm. Common on both slopes of Panama. This species can inflict most painful wounds with its fin spines, which bear poison glands at the base. Habitat: Both slopes of Panama. 4. Genus Trachycorystes Bleeker. Trachycorystes Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (type Trachycorystes typus Bleeker = Auchenipterus trachycorystes Cuvier & Valenciennes). Parauchenipterus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 88 (type Parauchenipterus galeatus Linnaeus). Body elongate or robust, covered with naked skin; occipital firmly joined to dorsal plate; lower jaw usually projecting; mandibular barbels in 2 pairs, one pair of maxillary barbels; teeth in villiform bands, none on vomer or palatines; eye small, lateral, covered with skin; dorsal with a spine and from 4 to 6 rays; adipose fin shorter than anal; caudal fin obliquely truncate, emarginate or rather deeply concave, the lobes round or pointed; outer margin of pectoral spine serrate. 4. Trachycorystes amblops (Meek & Hildebrand). Felichthys amblops Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 77 (Rio Tuyra, Marrigante, Panama). Head 3.7 to 4.35; depth 3.85 to 5.25; D. I, 5; A. 17 to 20. 344 FIELD MUSEUM OP NATURAL HISTORY — ZOOLOGY, VOL. X. Body rather robust; profile from snout to dorsal straight and gently elevated in female, concave in adult males; head depressed, its width i to 1.8 in its length; posterior part of body rather strongly compressed; snout short, broad, about equal to diameter of eye; eye 4.4 to 6.65 in head; interorbital 1.53 to 1.63; mouth broad; a pair of maxillary barbels, with a bone extending to anterior margin of eye in female, almost or quite to gill-opening in male; chin with 2 pairs of barbels; teeth in the jaws in bands; gill-opening small; dorsal plate rather broad; humeral process narrow, pointed slightly upward; dorsal spine in female some- what shorter than head, notably longer than head in the male, with barbels on its anterior margin, at least in young and in males; origin of dorsal more than half as far from tip of snout as from tip of adipose; adipose fin over posterior part of anal; caudal fin forked, both lobes pointed, equal to or longer than head; anal fin rather low, with heavy membrane on its base, length of its base shorter than width of head; ventral fins reaching origin of anal; dorsal fin not nearly reaching base of ventrals, the spine usually about equal to length of head. Color dark above, pale below; sides variously spotted or marked with black. Usually with a dark spot or elongate blotch on middle of side below dorsal; some specimens with roundish black spots on sides of head and caudal peduncle. Fins unmarked. Our largest specimen much darker than the others. There are 8 specimens in the present collection, ranging in length from 87 to 192 mm. All are from the lower Rio Tuyra. One specimen is from several miles above and the others from several miles below the head of the tide. This species is very closely related to T. fisheri Eigenmann, from which it differs mainly in the shape of the caudal, which has a much more concave margin, and longer and more pointed lobes. It also differs from the latter in the more posterior position of the dorsal and in the shorter anal. Habitat: Rio Tuyra Basin. 5. Genus Ageneiosus Lac6p£de. Ageneiosus Lace"pede, Hist. Nat. Poiss., V, 1805, 132 (type Ageneiosus armatus Lace"pede). Pseudageneiosus Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 108 (type Ageneiosus brevifilis Cuvier & Valenciennes). Body elongate; snout much longer than eye, with maxillary barbels only; eyes lateral; the orbit without a free margin; occipital process DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 245 firmly joined to the dorsal plate; humeral process wanting; gill-mem- branes joined to the isthmus; dorsal fin with a rather weak spine and 6 or 7 rays, its origin in advance of ventrals; adipose fin very short; anal fin long. 5. Ageneiosus caucanus Steindachner. Ageneiosus caucanus Steindachner, Denkschr. K. Ak. Wiss. Wien, XLI, 1880, 61, PI. VI, figs, i & 2 (Rio Cauca); Eigenmann & Eigenmann, Occ. Pap. Cal. Ac. Sci., I, 1890, 306. Head 3.5 to 3.8; depth 6.1 to 7.45; D. I, 6; A. 32 to 40. Body elongate, compressed; profile from snout to dorsal deeply con- cave in large males, only slightly concave in females; head low; snout very broad, much depressed, its length 1.77 to 2 in head; eye small, lateral, covered by a membrane, 5 to 10 in head; interorbital width 1.88 to 2.46; mouth wide, its width greater than length of snout; a pair of maxillary barbels present, very small in the female; with a stiff bone, extending to or beyond angle of mouth in the male; teeth in villiform bands, the one in upper jaw about as wide as eye, none on vomer or palatines; upper surface of head with a few rather prominent ridges and striations, covered with thin skin; a long narrow frontal fontanel; dorsal spine in the female rather weak and shorter than snout, much longer in the male, and with strongly developed barbs on its anterior side; origin of dorsal not much behind base of pectorals, a little more than half as far from tip of snout as from tip of adipose; adipose fin small, its base not longer than eye, over posterior fifth of anal; caudal fin forked, the lobes of about equal length; anal fin long, its base equal to or longer than head, the spine much more strongly developed in the male than in the female; ventral fins usually not quite reaching origin of anal; pectoral fins failing to reach ventrals, the spine 1.93 to 2.25 in head. Color yellowish creamy. The back in some specimens uniform bluish black. In others this color is broken up into stripes, or blotches. Sides with dark spots varying notably in size among the individuals. There is usually a series of spots forming a row from just above angle of gill-opening backward. Dorsal fin usually with dark spots. Caudal fin with a dark longitudinal bar on its upper lobe and a single blotch on the lower lobe. In very large examples both lobes bear several dark blotches, but no definite bar. Anal and ventrals unmarked; pectorals with or without a few dark blotches. There are 45 specimens of this species in the Panama collection. They range from 130 to 460 mm. in length. All are from the lower Rio Tuyra, some of them from below the head of tide water and others from as far up as Boca de Cupe. 246 FIELD MUSEUM OF NATURAL HISTORY — ZOSLOGY, VOL. X. We have at hand for comparison a few large male specimens from the Rio San Juan, Colombia. With these our specimens seem to agree in all characters of specific importance. Habitat: Rio Tuyra Basin, Panama, and south to Ecuador. Family II. Loricariidae. Sides and back and sometimes the lower surface covered with bony plates, these often provided with teeth-like spines; mouth wholly infe- rior, provided with reflected, disk-like lips; premaxillaries not pro- tractile; maxillary bone thin, bearing a barbel which is partly united with the oval disk; no mental or nasal barbels; teeth if present hooked and in a single series; no teeth on palatines; no frontal or occipital fontanel; nostrils close together; gill-membranes broadly joined to the isthmus; dorsal fin present, situated on the abdominal portion of the spinal column and not connected with the occipital by processes; adipose fin, if present, composed of a spine and a membrane; anal fin usually present, short; alimentary canal very long, coiled. MEASUREMENTS. In the present work the length of head in this family is measured to the margin of the temporal plates which usually extend to above base of pectorals; the total length of body is measured to tip of longest ray of caudal, exclusive of filament, if present; the standard length as usual is measured to base of caudal fin; by the mandibular ramii are meant the two bones bearing teeth, forming the posterior border of the mouth and corresponding to the lower jaw in other fishes. KEY TO THE GENERA. a. Body rather short, robust; caudal peduncle short, compressed; adipose fin usually present. b. Adipose and anal fins present. c. Scutes on back and sides distinctly carinate; opercle firmly attached to the interopercle and not independently movable. Plecostomus, p. 247 cc. Scutes on back and sides without prominent ridges or carinations; opercle more of less freely movable. d. Margin of snout naked, with or without tentacles. e. Snout without tentacles; mandibular ramus about equal to interorbital. Chcetostomus, p. 249. DEC. 28,1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 247 ee. Margin of snout bearing tentacles, long and numerous in the male, short and few in female; mandibular ramus much narrower than interorbital. Anctstrus, p. 250. dd. Margin of snout with granules and bristles; mandibular ramus notably shorter than interorbital. Lasiancistrus, p. 253. bb. Adipose and anal fins wanting; margin of snout granular, bear- ing short bristles; mandibular ramus nearly equal to interorbital. Leptoancistrus gen. nov., p. 254. aa. Body long and slender; caudal peduncle very long, strongly depressed; adipose fin wanting. f. Eye with a distinct orbital notch; teeth usually bifid, and in small or moderate numbers. Loricaria, p. 255. ff. Eye without an orbital notch; teeth setiform, numerous. Oxyloricaria, p. 261. 6. Genus Plecostomus Gronow. Plecostomus Gronow, Mus. Ichth., I, 1754, 24 (sp.); Gronow, Zooph. Gronov., 1763, 127; Sleeker, Nederl. Tijdschr. Dierk. I, 1863, 77 (type Pkcostomus brasiliensis Bleeker=Lon'can'a plecostomus Lin- naeus). Hypostomus Lac6p£de, Hist. Nat. Poiss., V, 1803, 144 (type Hypostomus guacari Lace"p6de). Body elongate; back and sides completely covered with carinate bony scutes; first scute of lower lateral series separating the second scute entirely from the temporal plate; lower surface of head and abdomen naked or covered with small granular scales; snout granular; opercle with or without marginal bristles, firmly attached to the interopercle and not capable of independent movement; premaxillaries and dentaries of about equal length, each with slender bifid teeth; adipose fin present; caudal fin emarginate. A large genus of which but one species is repre- sented in the rivers of Panama. 6. Plecostomus plecostomus (Linnaeus). Loricaria plecostomus Linnaeus, Syst. Nat., Ed. 12, I, 1766, 508 (America). Hypostomus guacari Lace*pede, Hist. Nat. Poiss., V, 1803, 145 (America). Loricaria flava Shaw, Gen. Zool., V, 1805, 38, PI. 101. Hypostomus plecostomus Schomburgk, Fishes Brit. Guiana, I, 1841, 139 (Rio Branco). Hypostomus robinii Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 46 (Trinidad). 248 FIELD MUSEUM OP NATURAL HISTORY — ZOOLOGY, VOL. X. Plecostomus brasiliensis Bleeker, "Silures de Suriname," 1864, 7 (Surinam). Plecostomus plecostomus Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd Ser., I, 1888, 169. Plecostomus seminudus Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd Ser., I, 1888, 169 (Brazil). Plecostomus boulengeri Eigenmann & Kennedy, Proc. Ac. Nat. Sci. Phila., 1903, 502 (Paraguay). Head 3 to 3.44; depth 4.4 to 5.3; D. I, 7; A. I, 4; lateral scutes 25 to 28. Body anteriorly depressed, wider than deep; caudal peduncle poste- riorly compressed; dorsal profile anteriorly convex; ventral surface straight, flat; head low and wide; snout broad, its margin granulate except a small triangular area at tip, 1.6 to 1.75 in head; eye 5.25 to 10; interorbital 2.2 to 2.9; mouth wholly inferior; the lips broad, expanded, forming a sucking disc; a single short barbel at angle of mouth; teeth placed on the ramii of the jaws, slender, bifid, curved inward near tip; the ramus of lower jaw 2 to 3.35 in interorbital; occipital and temporal plates each with a median ridge, the former bordered posteriorly by only a single scute; scutes on upper surface of body carinate, spinulose; 3 scutes in advance of dorsal; 6 or 7 between dorsal and adipose; 13 to 15 from anal to base of caudal; ventral surface in advance of vent mostly covered with small granular scales; dorsal fin inserted in advance of anal, nearer tip of snout than adipose fin, its base a little shorter than head, its spine usually about length of head, 2.9 to 3.75 in length; adipose fin well developed, situated somewhat nearer base of caudal than base of last ray of dorsal; caudal fin emarginate, the lobes produced, the lower one usually the longer; anal fin small, its origin a little behind base of last ray of dorsal; ventral fins rather large, reaching well past origin of anal; pectoral fins long, reaching far beyond base of ventrals, the spine much enlarged in adults, bearing recurved spinules. Color above dark green; head and ventral surface with green spots, these varying notably in size among individuals; fins usually bluish green, with large spots of pale green, those on lower fins arranged so as to form more or less distinct bars. This species is represented by 150 specimens, ranging in length from 40 to 400 mm. It was found fairly common on both slopes of Panama, except in the Rio Bayano Basin where no specimens were obtained. This fish lives in rocky streams and is difficult to catch with a seine. Most of our specimens were secured by the use of a set net, in which they readily become entangled. Habitat: Both slopes of Panama, south to Uruguay. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 249 7. Genus Chaetostomus Tschudi. Chcetostomus Tschudi, Fauna Peruana, Pise., XV, 1840, 489 (type Chcetostomus loborhynchus Tschudi). Body elongate, anteriorly depressed, wider than deep, ventral surface flat; head low, broad; snout obtuse, with a naked margin and without spines or tentacles; plates on head rather smooth, without ridges or carinations; back and sides covered with spinulate but not carinate scutes; lower surface of head and abdomen naked; mandibular ramus nearly equal to interorbital width. Adipose fin present. This genus is represented by a single species in Panama. 7. Chaetostomus fischeri Steindachner. Chatostomus fischeri Steindachner, Denkschr. K. Ak. Wiss. Wien, XLI, 1879, 162, PI. IV (Rio Mamoni, near Chepo); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 16; Regan, Trans. Zool. Soc. London, XVII, Pt. Ill, 1904, 248. Head 3 to 3.25; depth 5.15 to 6; D. I, 8; A. 1, 5; lateral scutes 24 or 25. Body anteriorly depressed; caudal peduncle posteriorly compressed; dorsal profile convex; ventral surface straight and flat; head low and wide, its upper surface spinulate, but without ridges or carinations; snout obtuse, its margin without granules, spines or tentacles, 1.5 to 1.65 in head; eye 6.7 to 9.3; interorbital 2.95 to 3.6; mouth wholly inferior, broad; the lips expanded, papilose, forming a sucking disc, the lower lip with small lobes along its posterior margin and a small barbel on its lateral margin near angle of mouth; teeth situated on the ramii of the jaws, small, numerous, slender, bifid and curved inward near the tips, the ramus of lower jaw i to 1.3 in interorbital; interopercle with i or 2 short spines; back and sides completely covered with spinu- late but not carinate scutes, 6 scutes between dorsal and adipose, 10 or ii from anal to base of caudal; lower surface of head and abdomen com- pletely naked; dorsal fin inserted a little in advance of base of ventrals, somewhat nearer tip of snout than adipose fin, its base equal to distance from the base of its last ray to tip of adipose, its spine 1.15 to 1.45 in head; adipose fin well developed, inserted slightly nearer base of upper ray of caudal than base of last ray of dorsal; caudal fin emarginate, the lower rays the longest; anal fin small, its origin a little behind last ray of dorsal; ventral fins reaching past origin of anal; pectoral fin large, reaching beyond middle of ventrals; the spines of all the fins with spinules. Color uniform black above; abdomen white. Tips of dorsal and caudal reddish in life. 250 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Of this species 62 specimens, ranging from 30 to 260 mm. in length, were preserved. It is common in the Rio Tuyra Basin, but only a few specimens were obtained in the Rio Bayano and a single specimen in the Rio Chagres. The last was speared at night by torch light by a native at Alhajuela. This species lives among the rocks, apparently prefering the rapid courses of streams. In clear water it may often be seen huddled close to the rocks to which it is able to attach itself by means of its sucking mouth and flat ventral surface. It feeds on algae and other plants. Its alimentary canal is convoluted and many times the length of the body. It is prepared as food by the natives of Darien, by boiling it in water. Habitat: Both slopes of Panama. 8. Genus Ancistrus Kner. Ancistrus Kner, Denkschr. K. Ak. Wiss. Wien, VII, 1853, 272 (sp.); Bleeker, Nederl. Tijdschr. Dierk., I, 1863, 77 (type Hypostomus cirrhosus Cuvier & Valenciennes). Thysanocara Regan, Ann. & Mag. Nat. Hist., Ser. 7, XVII, 1906, 95 (type Hypostomus cirrhosus Cuvier & Valenciennes). Body anteriorly broad; caudal peduncle posteriorly compressed; margin of snout naked, bearing tentacles; the naked margin broad in males and with many tentacles, narrow in the females and with few short tentacles; preopercle independently movable, bearing spines; the premaxillaries and dentaries of about equal length, the mandibular ramus much narrower than interorbital; plates on head and scutes on body without prominent ridges or carinations; adipose fin well developed. KEY TO THE SPECIES. a. Fins moderately elevated, the posterior rays of the dorsal failing to reach adipose when deflexed; base of dorsal scarcely equal to the distance from the base of the last ray to the tip of the spine of the adipose; pectoral fins failing to reach the middle of the ventrals, the spine notably shorter than the head; second scute behind occipital without a distinct median suture. chagresi, p. 251. aa. Fins strongly elevated, the posterior rays of dorsal reaching past origin of adipose when deflexed; base of dorsal equal to the distance from the base of the last ray to the base of caudal; pectoral fins reaching to or past the middle of ventrals, the spine longer than head; second scute behind occipital with an evident median suture. spinosus sp. nov., p. 252. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 251 8. Ancistrus chagresi Eigenmann & Eigenmann. Ancistrus cirrhosus (non Cuvier & Valenciennes) Kner & Steindachner, Abhandl. K. Beyer. Ak. Wiss. Munchen, X, 1864, 61 (Rio Chagres). Ch&tostomus cirrhosus Gunther, Trans. Zool. Soc. London, 1866, 478 (Rio Chagres). Ancistrus chagresi Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd Ser., II, 1889, 47 (Rio Chagres), and Occ. Pap. Cal. Ac. Sci., I, 1890, 446. Xenocara chagresi Regan, Trans. Zool. Soc. London, XVII, Pt. 3, 1904, 256 (Rio Chagres). Head 2.55 to 2.9; depth 4.7 to 5.75; D. I, 7; A. I, 3 or 4; lateral scutes 24 to 26. Body anteriorly broad, depressed; caudal peduncle posteriorly com- pressed; dorsal profile anteriorly gently convex; ventral surface straight and flat; head broad, the interorbital width nearly equal to depth of body, 2.05 to 2.3 in head; snout obtuse, the margin naked; naked portion broad in the males and narrow in females, in the former with well developed tentacles on the margin and a V-shaped patch above near tip of snout; tentacles varying much in number and length among indi- viduals; females with only a few short tentacles along or a little below the margin of snout; length of snout 1.6 to 1.75 in head; eye 7 to u; mouth rather wide; the lips expanded, with straight margin; barbel on lateral margin of lower lip minute; the premaxillaries quite as long as the dentaries; mandibular ramus 2.45 to 3.2 in interorbital width; teeth slender, bifid, curved inward near the tips; interopercle with from 9 to 15 spines of various lengths, which also vary much among individuals, longer in the male than in the female; sculpture of head without ridges or carinations; scutes on back and sides not carinate, but with strong serrations on their margins; occipital bordered by 3 scutes; the second median scute without a distinct median suture; 6 or 7 scutes between dorsal and adipose, n or 12 from anal to base of caudal; lower surface of head and abdomen naked; dorsal fin moderately elevated, the poste- rior rays when deflexed failing to reach adipose by at least one row of scutes, the spine 1.2 to 1.5 in head; base of dorsal scarcely equal to distance from base of last ray to tip of the spine of the adipose; adipose fin well developed; caudal fin with a straight oblique or slightly concave margin, the lower rays the longest; anal fin small, its origin at vertical from base of last ray of dorsal; ventral fins reaching past origin of anal; pectoral fins reaching past base of ventrals, but failing to reach the middle of these fins, the spine notably shorter than head. Color uniform dark above or occasionally with small greenish spots on head and predorsal region; abdomen usually with pale green spots 252 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. which vary in size, shape and number among individuals; fins all brown- ish green with pale green spots. The Panama collection contains 56 specimens, ranging from 45 to 255 mm. in length. Fifty-four of these are from the Rio Chagres Basin. The other two were taken in the Rio Chorrera, a small stream on the Pacific slope west of Panama City. Habitat: Rio Chagres and Rio Chorrera, Panama. 9. Ancistrus spinosus sp. nov. Type No. 8942, F. M. N. H.; length 135 mm.; Rio Calobre, tributary of the Rio Bayano, Panama. Head 2.65 to 2.77; depth 4.6 to 4.7; D. I, 7; A. I, 4; lateral scutes 24. Body broad anteriorly; caudal peduncle posteriorly compressed; head broad; interorbital width nearly equal to the depth of body, 1.95 in head; snout obtuse, the naked portion narrow hi the female and with only 4 small tentacles, much wider in the male with a fringe of tentacles along the margin and a V-shaped patch on the upper surface at the tip; length of snout 1.63 to 1.7 in head; eye 8.75; mouth wide; the lips expanded; the lower lip with a small barbel, shorter than eye, on its lateral margin; the premaxillaries and dentaries equal in length; man- dibular ramus 3.1 to 3.6 in interorbital width; teeth slender, bifid, curved inward near the tips; interopercle with from 8 to 12 spines, curved outward and forward near the apices, longer in the mate than in the female; sculpture of head without ridges or carinations; scutes on back and sides not carinate, their margins very strongly serrate, espe- cially in the male; occipital posteriorly bordered by 3 scutes; the second median scute with an evident median suture; 6 scutes between dorsal and adipose; n or 12 between anal and base of caudal; lower surface of head and abdomen naked; dorsal fin very high, the posterior rays when deflexed reaching past origin of adipose, the spine 1.15 to 1.2 in head; base of dorsal equal to distance from the base of its last ray to base of caudal; adipose fin well developed; caudal fin with a nearly straight oblique margin, the lower rays the longest; anal fin small, its origin slightly behind vertical from base of last ray of dorsal; ventral fins reaching well beyond base of anal; pectoral fins very long, reaching to or past the middle of ventral, the spine a little longer than the head. Color uniform dark above. The male plain brownish below; the female with faint pale spots on abdomen; fins in male plain brownish, in female with faint pale spots. Apparently a rare species. There are at hand only 2 specimens, a male and female, respectively 130 and 135 mm. in length. The male was taken at the mouth of the Rio Yape, tributary of the Rio Tuyra; <% -2 M .5 " 3 S s s not much compressed; ventral surface rounded; jaws much produced; teeth present on both jaws and maxillary, in a single series, directed backward, a small patch present on roof of mouth near tip of upper jaw; lateral line incomplete; scales large, pectinate; dorsal and anal inserted far backward. 46. Luciocharax beani (Fowler). Belonocharax beani Fowler, Proc. Ac. Nat. Sci. Phila., 1906, 464 (Rio Truando, tributary of the Rio Atrato). Ctenolucius hujeta (non Valenciennes) Bean, Proc. U. S. Nat. Mus., XXXIII, 1908, 701 (Rio Truando). Luciocharax striatus Boutenger, Ann. & Mag. Nat. Hist., Ser. 8, VII, 1911, 212 (Boca de Calima, Choco). Head 2.5 to 3.25; depth 5.9 to 9.1; D. 10; A. 10 or n; scales 47 to 50. Body long, not much compressed; the back not elevated; head long, flat above; snout long, slender, beak-like, 2 to 2.5 in head; eye 7.7 to 10; interorbital 4.85 to 7.7; mouth large, slightly oblique; upper jaw pro- jecting, ending in a fleshy point; lower Up developed into a flap on each side; maxillary slipping under suborbital, reaching opposite posterior margin of eye; teeth in the jaws sharply pointed, more or less lance- shaped, in a single series, all directed backward; the anterior ones in upper jaw somewhat enlarged and in advance of lower jaw; teeth in sides of jaws and maxillary small and very numerous; roof of mouth near tip of upper jaw with a small patch of conic teeth; gill-rakers poorly developed, 7 more or less developed on lower limb of first arch; lateral line present on 22 to 32 scales (in one specimen on only 16 scales) ; scales strongly striate and ctenoid, with pores; dorsal fin small, its origin half as far from base of caudal as from margin of preopercle; adipose fin well developed, a little nearer base of upper caudal rays than base of last dorsal ray; caudal fin forked, the lower lobe the larger; anal fin small, its origin under posterior rays of dorsal; ventral fins short, in- serted midway between base of pectorals and origin of anal; pectoral fins equal to or slightly shorter than postorbital part of head, inserted midway between tip of lower jaw and base of ventrals. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 303 Color steel blue above, silvery-white below; sides with alternating dark and pale stripes. The pale stripes occupy the middle of each row of scales and the black ones are between the rows, occupying a portion of 2 rows of scales. Base of caudal with a jet black spot, preceded by a pale area. Fins unmarked, the dorsal caudal and anal a little darker than the others. There are over 100 specimens of this species in the present collection, ranging in length from 70 to 325 mm. It was taken in the Rio Tuyra, and Rio Mamoni basins and in the Rio Marte Arnade and Rio Juan Diaz. We have for comparison specimens from the Rio Atrato Basin with which our specimens seem to agree perfectly. Habitat: Pacific slope of Panama and both slopes of Colombia. 32. Genus Hoplias Gill. Hoplias Gill, Proc. U. S. Nat. Mus., XXVI, 1903, 1015 (type Esox malabaricus Bloch). Macrodon Muller & Troschel, Horae Ichth., 1842, 6 (type Esox mala- baricus Bloch). (Preoccupied.) Body elongate, terete, slightly compressed; mouth large, with coni- cal teeth, some canine-like; palatines with teeth; maxillary for most part slipping under suborbital; no occipital process; no fontanel; air bladder present; no adipose fin; dorsal and anal fins short. KEY TO THE SPECIES. a. Scales in lateral line 42 to 44; n rows across caudal peduncle from one lateral line to the other; 5 complete rows between lateral line and base of anal. microlepis, p. 303. aa. Scales in lateral line 39 to 41 ; 9 rows across caudal peduncle from one lateral line to the other; 4 complete rows between lateral line and base of anal. malabaricus, p. 305. 47. Hoplias microlepis (Giinther). Perro Pesca or Pejeperro. Macrodon microlepis Gunther, Cat. Fish. Brit. Mus., V. 1864, 282 (Rio Chagres; Western Ecuador); Eigenmann & Eigenmann, Proc. Cal. Ac. Sci., 2nd Ser., 2, 1889, 102 (Obispo; Rio Chagres); Eigenmann, Ann. N. Y. Acad. Sci., 1889, 102; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 330; Boulenger, Boll. Mus. Torino, No. 329, XIII, 1898, i (Rio Daule and Rio Vinces, Ecuador). Macrodon trahira var. microlepis Steindachner, Denkschr. K. Ak. Wiss. Wien, XLI, 1880, 101 (Guayaquil). 304 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Hoplias microlepis Starks, Proc. U. S. Nat. Mus., XXX, 1906, 772 (Guayaquil); Regan, Biol. Cent. Amer., Pisces, 1907, 167 (Rio Chagres; western Ecuador); Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, Pt. IV, 1910, 447. Head 2.85 to 3.4; depth 4 to 5; D. 14, rarely 13; A. 10, rarely n; scales in lateral line 42 to 44. Body elongate, not much compressed, dorsal region not elevated; head long and low, slightly convex above; interorbital 3.2 to 5 in head; snout 3.45 to 4.6; eye 4.75 to 8.25; mouth large, lower jaw projecting; maxillary reaching beyond posterior margin of eye, mostly slipping under suborbital; teeth present on both jaws, and on palatines, the latter all small; some of the anterior teeth in jaws much enlarged, somewhat flattened, with very sharp cutting edges; gill-rakers poorly developed, 5 below angle on anterior arch; lateral line complete, straight, situated on median line of side; scales moderate, regularly placed, cycloid, 15 to 1 8 on median line in advance of dorsal; n, rarely 10, rows of scales across caudal peduncle from one lateral line to the other; 5 complete rows between the lateral line and anal fin; dorsal fin inserted midway between tip of upper jaw and base of caudal, or slightly nearer the former; adipose wanting; caudal fin convex; anal fin inserted posteriorly, the longest ray reaching nearly to base of lower caudal ray; ventral fins inserted under base of pectorals, slightly nearer base of caudal than tip of lower jaw; pectoral fins inserted slightly behind margin of preopercle, failing to reach base of ventrals by 4 or 5 rows of scales. Color of large specimens very dark brown above, lighter below, uniform, without band or blotches; young much paler, mottled with brown and with a more or less distinct dark lateral band. The dark mottlings of the young later appear to become concentrated into dark blotches along the side. The dark lateral band is much more persistant in some specimens than in others. Fins all with dark spots forming more or less distinct wavy bars. There are 175 specimens, ranging from 27 to 460 mm. in length, in the present collection. It was found in all streams visited on both slopes of Panama, except in the Rio Tuyra Basin where it is replaced by H. malabaricus. A very abundant fish in lowland streams, usually preferring shallow water where there is an abundance of vegetation. It is called, "Perro Pesca"= dog fish, by the natives because of its large sharp teeth and its habit of snapping at objects coming near it. Care must be exercised in picking specimens from the net, as it is able to inflict painful wounds with its sharp teeth and powerful jaws. This fish, although used to some extent as food, is not regarded as of good flavor and is of minor importance. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 305 We have for comparison specimens from western Ecuador, which seem to be identical with the Panama specimens. Habitat: Both slopes of Panama, except in the Rio Tuyra Basin, and the western slope of Ecuador. 48. Hoplias malabaricus (Bloch). Esox malabaricus Bloch, Naturgesch. der Ausland. Fische, Pt. 8, 1794, 149, PI. 392 (Tranquebar, locality wrongly given). Synodus malabaricus Bloch & Schneider, Syst. Ichth., 1801, 397. Synodus tareira Bloch & Schneider, Syst. Ichth., 1801, 398, PI. 79. Macrodon tareira Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 1846, 508 (Bahia; San Francisco; Amazon; Maracaibo). Eryihrinus trahira Agassiz, Spix, Piscium Brasil., 1829, PI. 18 (Bahia). Macrodon trahira Muller & Troschel, in Schomburgk, Reisen in Brit- isch-Guiana, Fische, III, 1848, 632. Erythrinus macrodon Agassiz, Spix, Piscium Brasil., 1829, 43, PL 18 (Alma, Prov. Bahia; San Francisco). Erythrinus microcephalus Agassiz, Spix, Piscium Brasil., 1829, 44 (San Francisco). Erythrinus brasiliensis Agassiz, Spix, Piscium Brasil., 1829, 45, PI. 20 (Peruaguacu). Macrodon guavina Valenciennes, Humboldt Observ. Zool., II, 1833, 179, PL 48, fig. i. Macrodon auritus Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 1846, 519 (Montevideo). Macrodon teres Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 1846, 521 (Lake Maracaibo). Macrodon patana Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 1846, 522 (Cayenne). Macrodon aimara Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 1846, 523, pi. 586 (Cayenne). Macrodon ferox Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 51 (Trinidad, W. I.). Macrodon intermedius Gunther, Cat. Fish. Brit. Mus., V, 1864, 282 (Cipo River). Macrodon malabaricus Eigenmann & Eigenmann, Cal. Ac. Sci., 2nd Ser., 2, 1889, 102. Hoplias malabaricus Gill, Proc. U. S. Nat. Mus., XXVI, 1903, 1015. Head 2.15 to 3.3; depth 4.3 to 5; D. 13 or 14; A. 10 or n; scales in lateral line 39 to 41. Body elongate, not much compressed, dorsal region not elevated; head long and low, slightly convex above; interorbital space 3.65 to 306 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 4.25 in head; snout 3.7 to 4.37; eye 4.65 to 6.8; mouth large; lower jaw projecting; maxillary reaching past posterior margin of eye, mostly slipping under suborbital; teeth as in preceding species; gill-rakers poorly developed, 5 below angle on anterior arch; lateral line complete, straight, occupying median line of side; scales large, regularly placed, cycloid, 15 to 17 on median line in advance of dorsal; 9 scales across caudal peduncle from one lateral line to the other; 4 complete rows of scales between lateral line and anal fin; dorsal fin inserted midway between tip of upper jaw and base of caudal or slightly nearer the former; adipose fin wanting; caudal fin convex; anal fin inserted poste- riorly, the longest rays not quite reaching base of lower caudal rays; ventral fins inserted under base of dorsal, a little nearer base of caudal than tip of lower jaw; pectoral fins inserted behind margin of preopercle, failing to reach base of ventrals by 4 or 5 rows of scales. Color as in preceding species. Of this species 8 specimens were preserved. They range in length from 85 to 295 mm. All are from the Rio Tuyra Basin. This species is closely related to the preceding, differing mainly in the slightly larger scales. Our specimens were compared with specimens from the Rio Atrato Basin, with which they appear to agree perfectly. Habitat: Rio Tuyra Basin; both slopes of Colombia; Ecuador, and south to Brazil. Family VII. Gymnotidae. Body elongate, more or less eel-shaped; with or without scales; vertebrae many; skull with or without a frontal fontanel; parietal fon- tanel always present; mouth with or without teeth; margin of upper jaw formed by maxillaries and premaxillaries; air-bladder in 2 parts, connected by a small tube; vent well forward, never behind tips of pectorals, usually under head; dorsal fin wanting, or represented by a filament; caudal fin present or more usually absent, the tail terminating in a pointed appendage when fin is wanting; anal fin very long; ventral fins wanting; pectoral fins present, small. KEY TO THE GENERA. a. Frontal fontanel wanting. Gymnotus, p. 307. aa. Frontal and parietal fontanels present. b. Caudal fin and dorsal filament wanting. c. Orbital margin free; teeth present in both jaws, in 2 more or less distinct patches in upper jaw and in a single patch in lower jaw. Sternopygus, p. 308. DEC. 28, 1916. FISHES or PANAMA — MEEK AND HILDEBRAND. 307 cc. Orbital margin not free; eye covered by a transparent mem- brane. d. Teeth wanting; origin of anal about the length of pectoral fin behind gill-opening. Hypopomus, p. 309. dd. Teeth present in both jaws; origin of anal under or slightly behind base of pectorals. Eigenmannia, p. 311. bb. Caudal fin and dorsal filament present; mouth large, its angle little, if any, in front of eyes. Sternarchus, p. 312. 33. Genus Gymnotus Linnaeus. Gymnotus Linnaeus, Syst. Nat., Ed. X, 1758, 246 (type Gymnotus carapo Linnaeus). Size moderate, not exceeding 600 mm. in length. No frontal fon- tanel; no caudal fin; a dorsal filament; no electrical organs; cylindrical anteriorly, somewhat compressed posteriorly; head large and depressed, the top quite flat; gape not reaching the eyes; lower jaw protruding; teeth small, conical, in one row (which is sometimes irregular) in each jaw; eyes small and covered by membrane, without free orbital margin; scales cycloid and very small; lateral line complete and paralleling the main axis of the body; pectorals small; anal long, its origin back of vertical from the tip of the pectoral. (Ellis.) Of this genus only a single widely distributed species is known. 49. Gymnotus carapo Linnaeus. Gymnotus carapo Linnaeus, Syst. Nat., Ed. X, 1758, 246, and Ed. XII, 1766, 427; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., VII, 1907, 135 (LosAmates and Lake Amatitlan, Guatemala) ; Ellis, Memoir. Carnegie Mus., VI, 1913, 117 (Guatemala, south to the Rio de la Plata and the West Indies). Gymnotus fasciatus Pallas, Spicil. Zool., VII, 1769, 35; Schomburgk, Fishes of Guiana, 1843, 184, PI. 19 (Rio Branco). Gymnotus albus Pallas, Spicil. Zool., VII, 1769, 36 (Surinam). Gymnotus brachyurus Bloch, Syst. Ichthyol. 1787, Taf. 157, fig. i. Gymnotus putaol Lace"pede, Hist. Nat. Poiss., II, 1800, 176. Carapus fasciatus Cuvier, Regne Animal, Ed. I, II, 1817, 237. Carapus brachiurus Cuvier, R£gne Animal, Ed. I, II, 1817, 237. Carapus inaquildbiatus Valenciennes, in d'Orbigny, Voy. Ame"r. Me"rid., V, Pt. 2, 1847, u, PI. 14 (La Plata). Giton fasciatus Kaup, in Dumeril, Analyt. Ichthyol., 1856, 201; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 340 (Guatemala to Rio de la Plata). 308 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. "Head 7.25 (old individuals) to n (young individuals) ; depth 8.5 to 14 in length to end of the anal; anal rays 200 to 260. "Snout 2.5 to 3; interorbital 2.25 to 3 in head; eye 4 (young) to 7 in the snout, 4.25 to 6 in the interorbital, 10 to 6 in the head. "Body cylindrical; head depressed; width of head 1.25 to 1.6, depth of head at base of the occipital process 1.3 to 1.8 in the greatest depth; anus near the vertical from a point the length of the snout behind the eye; dorsal profile almost straight; ventral profile slightly convex. "Snout very slightly pointed in young specimens, blunt in adults; mouth rather large; gape straight, reaching about two-thirds of the distance to almost below the eye; upper jaw included; caudal peduncle one-half the length of the snout or less; pectorals 2.25 to 3 in the head; origin of the anal behind pectorals, on the vertical from a point about 1.5 times the snout behind the head. "Ground-color of alcoholic specimens varies from a light slate-gray in young specimens to a light orange in adults; a series of transverse white stripes crossing the body in young individuals, which widen and become yellow with age so that the adults are yellow, barred with black; dorsal parts washed with a dark chocolate-brown containing numerous black spots; fins translucent, mottled with black or brown. "In life the body is translucent, flesh color or pale yellow, vary- ing to a distinct pink in the parts rich in blood. The stripes and markings are blue or green, giving the fish a purplish or olive-green cast. This color may be deepened or lightened slightly by the ex- pansion and contraction of chromatophores. "The general marking of the species varies considerably, specimens from clear water being darker and more striped than those from muddy water. Some specimens from Guatemala and from the Upper Paraguay are almost without markings." (Ellis) This species was not taken in Panama, but it is here included because it has been recorded from Central and South America, thus coming within the range of the present work. Habitat: Guatemala south to the Rio de la Plata, and the West Indies. 34. Genus Sternopygus Muller & Troschel. Sternopygus Muller & Troschel, Horae Ichthyol., III, 1849, 13 (type Gymnotus macrurus Block & Schneider). Differing from all other Gymnotids in the free orbital margin. Body elongate, compressed; head moderate; snout short; jaws equal, or the upper a little in advance of the lower, the latter included at sides; teeth minute, in 2 more or less distinct patches in upper jaw, in a single patch DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 309 in lower jaw; frontal and parietal fontanels present; caudal peduncle round or compressed, without caudal fin; scales small, cycloid; lateral line complete; origin of anal in pectoral region; posterior air bladder conic. Size moderate or rather large. 59. Sternopygus dariensis sp. nov. Type No. 8949, F. M. N. H.; length 300 mm.; Marrigante, Rio Tuyra, Panama. Head 5.95 to 7.7 in length to end of anal; depth 6.65 to 7.8; A. 256 to 292. Body elongate, more or less eel-shaped, compressed; head small, its upper profile usually slightly concave; snout rather slender, not much deeper than wide, its length 2.2 to 3 in head; eye small, with a free orbital margin, 3.1 to 7.25 in snout; interorbital 4.85 to 6.66 in head; mouth moderate, the gape reaching about half way to eye; upper jaw a little in advance of the lower, the latter included at sides; teeth in the jaws villiform, those of the upper jaw separated into two patches by a median line; gill-slit scarcely as long as snout; vent 3 or 4 times diameter of eye behind vertical from posterior margin of orbit; caudal peduncle varying in length, from notably shorter than head to a little longer than head, rather robust, compressed; lateral line complete, following the outline of the back; scales very small, cycloid; origin of anal below or a little behind base of pectorals, the longest rays a little shorter than snout; pectoral fins small, 2.1 to 2.75 in head. Color grayish brown, the back slightly darker than the rest of body; sides with numerous dusky punctulations. Fins unmarked. This species is represented by 25 specimens, ranging from 124 to 810 mm. in length. All were taken below the head of tide water at Marrigante on the Rio Tuyra. We have designated as the type a specimen 300 mm. in length. This species differs from S. macrurus, its nearest relative, in the slightly concave profile of head, more slender snout, smaller eye, nar- rower interorbital, in the shorter and much heavier tail, and in the slightly more posterior position of the vent. 35. Genus Hypopomus Gill. Hypopomus Gill, Proc. Ac. Nat. Sci. Phila., 1864, 152 (type Rham- phichthys mulleri Kaup). Brachyrhamphichthys Gunther, Cat. Fish. Brit. Mus., VIII, 1870, 6 (type Rhamphichthys artedi Kaup). 3io FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Body elongate, compressed; size small; head short; snout blunt; frontal and parietal fontanels well developed; mouth small; teeth wanting; eyes covered by a transparent membrane; scales small, cycloid; lateral line complete; no caudal fin; origin of anal about the length of pectoral fin behind vertical from gill-opening. 51. Hypopomus brevirostris (Steindachner). Rhamphichthys breviroslris Steindachner, Sitzb. K. Ak. Wiss. Wien, LVIII, 1868, 254, PI. II, fig. 2 (Guapore"); Gunther, Cat. Fish. Brit. Mus., VIII, 1870, 6; Steindachner, Denkschr. K. Ak. Wiss. Wien, XLI, 1880, 89 (Rio Guapore", Amazon stream near San- tarem, and Rio Cauca). Brachyrhamphichthys brevirostris Eigenmann & Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 62. Hypopomus brevirostris Eigenmann & Kennedy, Proc. Ac. Nat. Sci. Phila., 1903, 530 (Campo Grande, Arroyo Chagalalina) ; Ellis, Memoir. Carnegie Mus., VI, 1913, 134, fig. 7; Eigenmann & Fisher, Indiana Univ. Studies, No. 25, 1914, 236 (Rivers of Colombia). Hypopomus occidentalis Regan, Ann. & Mag. Nat. Hist., Ser. 8, XIV, 1914, 32. Head in length to end of anal fin 6.8 to 9.3; depth 6.8 to 9; A. 213 to 238. Body elongate, rather strongly compressed; caudal filament ribbon- shaped, pointed; upper profile of head and body gently convex; head short; snout blunt, 3 to 3.55 in head; eye small, covered with a trans- parent membrane, 9 to 12 in head; interorbital 4 to 4.35; mouth small; jaws subequal, the lower slightly included; maxillary about twice the length of eye; teeth wanting; no mental filaments; lateral line becoming obscure posteriorly; scales small, cycloid; caudal filament 1.12 to 1.2 in length to end of anal; vent under preopercular margin, from 2 to 3.5 times diameter of eye behind vertical from posterior margin of orbit; origin of anal fin a little in advance of tips of pectorals, or about the snout's length behind base of these fins; pectoral fins short, 1.65 to 2 in head. Color brownish or buff, with darker markings of varying sizes, some- times forming more or less distinct cross-bars on anterior portion of body. This fish is represented by 4 specimens ranging from 68 to 162 mm. in length. Two of our specimens are from the Rio Chagres Basin and the other two from the Rio Bayano Basin. Habitat: Both slopes of Panama and Colombia and south to the Rio de la Plata. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 311 36. Genus Eigenmannia Jordan & Evermann. Cryptops Eigenmann, Ann. N. Y. Ac. Sci., VII, 1894, 626 (type Sterno- pygus humboldtii Steindachner=S/ernarc/ws virescens Valenciennes). (Name preoccupied.) Eigenmannia Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 341. (Substituted for Cryptops.) This genus is distinguished from Sternopygus by the absence of a free orbital margin. Body elongate, compressed; head rather small; snout blunt; mouth small; jaws equal, or the lower included; a large frontal and parietal fontanel present; eyes medium, covered by a transparent membrane; teeth in upper jaw in 2 almost confluent patches, those of lower jaw in 2 lateral patches; scales small, cycloid; lateral line complete; origin of anal back of vertical from origin of pectorals; caudal filament moderate or long. Size moderate, not exceeding 400 mm. 52. Eigenmannia virescens (Valenciennes). Sternarchus virescens Valenciennes, in d'Orbigny, Voy. Ame'r. Me*rid., V, Pt. 2, 1847, u, PI. 13, fig. 2. Sternarchus virescens Muller & Troschel, in Schomburgk, Reisen in Britisch-Guiana, Fische, III, 1848, 640 (Guiana); Gunther, Cat. Fish. Brit. Mus., VIII, 1870, 7 (Surinam). Sternopygus lineatus Muller & Troschel, in Schomburgk, Reisen in Britisch-Guiana, Fische, III, 1848, 640 (Guiana). Sternopygus tumijrons Muller & Troschel, Horae Ichthyol., Ill, 1849, 14. Sternopygus humboldtii Steindachner, Denkschr. K. Ak. Wiss. Wien, XXXIX, 1878, 71, PI. XIV (Rio Magdalena). Cryptops virescens Eigenmann, Ann. N. Y. Ac. Sci., VII, 1894, 626. Cryptops lineatus Eigenmann, Ann. N. Y. Ac. Sci., VII, 1894, 635. Cryptops humboldtii Eigenmann, Ann. N. Y. Ac. Sci., VII, 1894, 625. Eigenmannia humboldtii Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 341. Head 6.05 to 7.15 in length to end of anal fin; depth 5.7 to 7; A. 165. Body elongate, compressed; dorsal profile of head and body convex; head short; snout blunt, its length 2.85 to 3.3 in head; eye moderate, 4.9 to 5.7; interorbital 3 to 3.2; mouth small; jaws subequal, the lower included, at least on sides; maxillary about equal to length of eye; teeth in the upper jaw in 2 nearly confluent patches, those in lower jaw in 2 lateral patches; vent about one-half diameter of eye behind vertical from posterior margin of orbit; caudal filament in our small specimen flat, ribbon-shaped and more than half the length of anal, lost in the 312 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. larger specimen; origin of anal slightly behind origin of pectorals, the longest rays but little shorter than eye and snout; pectorals of moderate length, 1.17 to 1.2 in head. Color grayish buff; sides with dark points, forming an indistinct dark area at beginning of lateral line and an indefinite dark streak on lateral line, and short bars below base of anal rays; fins unmarked. Of this species we have only 2 specimens and the largest one is with- out a tail. The smallest one measures 150 mm. in total length. Both are from Marrigante, below the head of tide water on the Rio Tuyra. We have at hand for comparison many specimens from more south- ern localities. Our uninjured specimen appears to differ somewhat from all the others that have been examined in the apparently deeper body, shorter anal fin and the compressed caudal filament, which is considerably longer than half the anal. It is, therefore, probable that our specimens represent a new variety or species, but our material is too meagre to establish this fact. Habitat: Rio Tuyra south to the Rio de la Plata. 37. Genus Sternarchus Bloch & Schneider. Sternarchus Bloch & Schneider, Syst. Ichthyol., 1801, 497, PI. 94 (type Gymnotus albifrons Linnaeus). Body elongate, compressed; head large, naked; snout short, not tubu- lar; fontanels present; eyes without free orbital margin; mouth large, its angle little if any in advance of eyes; teeth in patches on both jaws; scales cycloid; lateral line complete; caudal fin present, distinct; anal fin long, but not reaching caudal fin, its origin at or a little in advance of vertical from gill-opening. 53. Sternarchus rostratus Meek & Hildebrand. Sternarchus rostratus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 85 (Rio Grande near Cana). Head 6.7 in length to base of caudal; depth 8.25. Body compressed throughout; head rather low, its greatest depth 1.8 in its length, its upper profile slightly concave; snout not greatly produced, blunt, very slightly compressed, its length somewhat greater than distance from anterior margin of eye to upper angle of gill- opening, 2.3 in head; eye 18.5; interorbital 5.6; mouth rather large, its angle under about middle of eye; upper jaw a little in advance of the lower; gill-opening a small slit in advance of pectorals; lateral line com- plete; mucus pores numerous and distinct on back and sides; vent under margin of preopercle; dorsal filament present; caudal fin distinct, DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 313 rounded, not much longer than interorbital width; origin of anal slightly in advance of gill-opening, its longest rays equal to or a little shorter than snout; pectoral fins equal to half length of head. Color uniform brownish, without dark punctulations; a very distinct yellowish stripe on median line of snout and back, disappearing at origin of dorsal filament. Fins unmarked. Of this species only a single specimen was secured, measuring 126 mm. in length. It was taken in the Rio Grande, tributary of the Rio Tuyra, several miles above Cana. Several others were seen, floating down stream after a discharge of dynamite, but before they could be reached they had apparently recovered from the shock and quickly disappeared. We compared our specimen with several from the Rio Cauca, at Cali, Colombia, and found them to be identical. Order III. Haplomi. THE PIKE-LIKE FISHES. Body elongate; scales cycloid, extending on head; lateral line wanting; fin rays soft; dorsal fin single, placed posteriorly; ventral fins abdominal. Opercles well developed; mesocoracoid absent; hyper- coracoid and hypocoracoid separate; pharyngeal bones distinct. Family VIII. Poeciliidae. THE KILLIFISHES. Body oblong to more or less elongate; depressed anteriorly, com- pressed posteriorly, covered with rather large cycloid scales; head usually flat above; mouth protractile, bordered above by the premaxillaries; jaws with teeth, incisor-like to villiform; gill -membranes more or less con- nected, free from the isthmus; gill-rakers short and thick; dorsal fin single, of soft rays only; ventral fins abdominal; caudal fin usually rounded or truncate. The species of this family are very numerous; some of them are viviparous. Those which occur in the area under consideration in this work are all viviparous, except the ones belonging to the genus Rivulus. Mr. Regan of the British Museum has lately revised the subfamily PoeciliincB, basing his classification of the genera on the modified anal 314 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. fin of the males. Since, with two exceptions, all the species treated of here belong to this subfamily, we have followed for the most part Mr. Regan's classification. However, in as much as the modified anal fin of the males vary so essentially in different species, its use as a generic character seems to us to lead to too many divisions, resulting in nearly as many genera as species. It is, therefore, our opinion that this char- acter should be regarded of specific, rather than of generic importance. KEY TO THE GENERA. a. Males with the anal fin advanced and modified into an intro- mittent organ. Species viviparous. b. Ventral fins similar in both sexes. c. Mouth not wholly transverse, the cleft partly lateral; teeth conical, immovable. d. Distal portion of produced rays of anal fin in male directed back- ward, usually with one or more retrorse spines or hooks. Gambusia, p. 314. dd. Distal portion of produced rays of anal in male directed forward, with or without antrorse hooks. Priapichthys, p. 319. cc. Mouth transverse; teeth slightly compressed, movable; the intromittent organ long and slender, without hooks or serrations at apex. Pceciliopsis, p. 324. bb. Ventral fins in the male enlarged, the second ray notably pro- duced; teeth in the jaws movable; the first prolonged ray of anal fin in male bearing a small antrorse hook at apex. Mollienisia, p. 326. aa. Anal fin in the males not modified into an intromittent organ. Species ©viviparous. Rivulus, p. 330. 38. Genus Gambusia Poey. Gambusia Poey, Memorias, I, 1855, 382 (type Gambusia punctata Poey). Gambusia Regan, Proc. Zool. Soc. Lond., 1913, 981. Body elongate, moderately compressed in the female; mouth small, the branches of the lower jaw firmly united; teeth fixed, conical, in bands, the outer ones slightly the larger; branchiostegals 6; anal fin of female more or less in advance of the dorsal; anal of male much ad- vanced, its anterior rays modified into an intromittent organ; alimentary canal short; vertebrae about 32; viviparous. This genus, as restricted by Regan, includes species in which the modified anal of the male is about ^ the length of the body of the fish and is formed of three rays. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 315 "The distal segments of the first prolonged ray are produced into processes directed more or less towards its apex; the anterior branch of the second prolonged ray is slender distally and at some distance from the end has an antrorse projection which may be termed the ' elbow' ; the posterior branch of this ray ends in a retrorse pointed hook or barb, and the segments immediately proximal to the elbow of the anterior branch are produced backwards into serrse; the third prolonged ray ends in a hook more or less similar to that of the second." (Regan) The males of this genus and related genera are smaller than the females, and more elongate; they are apparently fewer in number. All Gambusia are small, and as a net sufficiently small to capture females will permit the males to pass through it, the few males taken by the collector may not indicate their true ratio. Many of the species of this genus live in swamps and lowland streams, but a few species throughout Mexico and Central America are found in clear mountain streams at as high an altitude as any fishes are found. Gambusia feed chiefly on insects and small Crustacea. To some of the species are credited the eating of mosquito larvae. We here tentatively refer to this genus 2 species, G. episcopi and G. cascajalensis, that do not have any definite retrorse hooks on the distal portion of the intromittent organ, but they agree in other respects with this genus. KEY TO THE SPECIES. a. Intromittent organ of male with 2 strong retrorse hooks at apex, and anteriorly with strong serrations; each scale with a dark dot, forming lines along the rows of scales; dorsal and caudal with black spots, forming bars. nicaraguensis, p. 316. aa. Intromittent organ of male without retrorse hooks or strong serrations at apex; no dark lines along the rows of scales; anal fin with a black spot at base, which may or may not be extended to tip of rays. b. Body rather robust, the depth 3.2 to 4.1 in length; caudal ped- uncle 1.15 to 1.6 in head; origin of dorsal in female over or slightly anterior to vertical from middle of anal; anal fin not falcate; skin underneath the scales strongly pigmented, mark- ing the margins of the scales; sides with more or less distinct dark spots or bars. Largest females 52 mm. in length. episcopi, p. 317. bb. Body slender, the depth 3.7 to 4.5 in length; caudal peduncle 1.7 to 2 in head; origin of dorsal in female over posterior rays of anal; anal more or less falcate; the rows of scales very indis- tinctly marked; sides without spots or bars. Largest female 62 mm. in length. cascajalensis, p. 318. 316 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 54. Ganibusia nicaraguensis Gunther. Gambusia nicaraguensis Gunther, Cat. Fish. Brit. Mus., VI, 1866, 336, and Trans. Zool. Soc. London, 1868, 483, PI. 82, fig. 3 (Lake Nicaragua); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 682; Regan, Biol. Cent. Amer., Pisces, 1907, 96 (Lake Nicaragua; El Hule, Mexico), and Proc. Zool. Soc. London, 1913, 985, fig. 168 A (Lake Nicaragua; El Hule and Coaxacoalcos, Mexico). Paragambusia nicaraguensis Meek, Field Col. Mus. Pub., Zool. Ser., V, 1904, 133 (Otopa; Boca del Rio; El Hule; Obispo; Perez). Head 3.3 to 3. 8; depth 3. 3 to 3. 8; D. 7018; A. loom; scales 29 to 31. Body elongate, compressed; upper profile from snout to dorsal straight or slightly convex; head rather low, flat above; snout short, 2.7 to 3.8 in head; eye 2.8 to 3.5; interorbital 2 to 2.9; mouth very small, the gape extending only about half way to eye; teeth in jaws in villiform bands; gill-rakers short, about 14 on lower limb of first arch; scales moderate, cycloid, extending forward to eyes; caudal peduncle strongly compressed, its least depth 1.5 to 1.8 in head; origin of dorsal in female over or slightly behind base of last ray of anal, or about midway between posterior margin of eye and tip of caudal, in male notably behind base of last ray of anal and about midway between tip of snout and tip of caudal ; caudal fin rounded; anal fin in female inserted somewhat nearer tip of snout than tip of caudal, its outer margin concave, in adult male it is inserted about midway between tip of snout and base of caudal, the longest modified ray 2.6 to 2.8 in body, the first produced ray with strong serrations on distal portion and the posterior branch of second and third produced rays each with a strong retrorse hook at apex; ventral fins small, reaching origin of anal in female, and past origin of anal in male; pectoral fins moderate, 1.5 to 1.85 in head. FIG. 4. DISTAL PART OF INTROMITTENT ORGAN OF Gambusia nicoragutnsis Gunther. (Greatly magnified.) Color greenish; each scale on upper part of sides with a dark dot, forming lines along the rows of scales. Dorsal and caudal with black spots forming bars; other fins unmarked. Of this species we have over 100 specimens. The largest female is 45 and the largest male 27 mm. in length. Nearly all of our specimens DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 317 are from brackish water on the Atlantic coast. We have a single female specimen from brackish water from the Pacific coast, which we doubtfully refer to this species. Habitat: Southern Mexico south to Panama. 55. Gambusia episcopl Steindachner. Gantbusia episcopi Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXVII, 1878, 387, PI. II, figs. 3 & 4 (Obispo, Panama) ; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 683 (Ditches on the Isth- mus of Panama, Obispo Station); Garman, Mem. Mus. Comp. Zool., XIX, 1895, 88 (Panama Railroad between Gorgona and Matachin); Regan, Biol. Cent. Amer., Pisces, 1907, 96. Gambusia latipunctata Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Sen, X, 1913, 87 (Araijan, Panama). Head 3. i to 3.5; depth 3. 2 to 4.1; D. 8 or 9; A. 9 or 10; scales 26 to 28. Body rather robust; profile from snout to nape straight, from nape to dorsal slightly convex; head flat above; snout rather short 3.2 to 4 in head; eye 3 to 3.7; interorbital 2 to 2.6; mouth moderate, the cleft reaching about half the distance to eye; teeth in the jaws pointed, in bands, the outer ones scarcely enlarged; scales large, cycloid, extending forward to eyes, 6 longitudinal rows between anterior part of base of dorsal and base of anal; caudal peduncle strongly compressed, its least depth, 1.15 to 1.6 in head; origin of dorsal in female over middle of base of anal, or slightly anterior to this point, and somewhat nearer anterior margin of eye than tip of caudal; in the adult male the origin of the dorsal is a little nearer end of snout than tip of caudal; caudal fin rounded; anal fin in female usually inserted a little nearer end of snout than tip of caudal, the anterior rays scarcely produced; in the adult male the origin of the anal is slightly nearer base of caudal than end of snout, the modified portion of anal failing to reach base of caudal by about the length of postorbital part of head, equal to or a little longer than head, 3.4 to 3.85 in length of body, the apex scarcely bent backward, no hooks, the two branches of the second ray and the third ray of about equal length and the anterior ray only slightly shorter than the second and third; ventral fins rather small, reaching vent in female, reaching to or past origin of anal in male; pectoral fins reaching slightly past base of ventral, 1.3 to 1.55 in head. Color rather variable, apparently depending largely upon the clear- ness of the water in which they live. The sexes similarly colored, olivaceous, with dusky punctulations, which are mostly on the skin underneath the scales, making it appear as if the scales were margined with dark; this dark coloration is much more prominent on some in- 3i 8 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. dividuals than others; sides with more or less distinct dark spots. In the specimens in which they are most distinct they form short, vertical bars, and in others they appear as quadrate spots. Dorsal fin with black chromatophores preceding each ray, forming a dark bar near the base; interradial membranes between the posterior rays of anal with black chromatophores, forming a dark spot at base of fin, these chro- matophores may or may not be extended on the rays and up the fin. All intergradations from an obscure spot at base of the rays to a promi- nent spot, with the black extending nearly to the tips of the rays, occur. A fairly common species on both slopes of Panama, occurring mainly in the upper courses of creeks. Numerous specimens are at hand. The FIG. 5. DISTAL PART OF INTROMITTENT ORGAN OF Gambusia tpiscoti Steindachner. (Greatly magnified.) largest female is 52 and the largest male 23 mm. in length. It was not taken in the Rio Tuyra or Rio Bayano basins. Further study of our material convinces us that the form we de- scribed as Gambusia latipunctata in 1913 intergrades with the present species and is therefore not valid. Habitat: Both slopes of Panama, north of the Rio Bayano. 56. Gambusia cascajalensis Meek & Hildebrand. Gambusia cascajalensis Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 86 (Rio Cascajal, Porto Bello, Panama). Head 3.2 to 3.9; depth 3.7 to 4.5; D. 7 or 8; A. 10; scales 28 to 30. Body rather slender; the profile straight over the head, slightly convex from nape to dorsal; head rather flat above; snout moderate, 3.1 to 3.35 in head; eye 2.8 to 3.25; interorbital 2.1 to 2.4; mouth rather small, the cleft extending about one-third the distance to eye; teeth in the jaws pointed, in bands, the outer ones slightly enlarged; scales moderate, cycloid, extending forward on snout and on base of caudal fin, 7 longitudinal rows between anterior part of base of dorsal and base of anal; caudal peduncle strongly compressed, its least depth 1.7 to 2 in head; origin of dorsal in female over posterior rays of anal, and about midway between middle of eye and tip of caudal, in the male its origin DEC. 28,1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 319 is slightly nearer tip of caudal than tip of snout; caudal fin rounded; anal fin in female inserted a little nearer tip of snout than tip of caudal, the anterior rays somewhat produced; in the adult male the origin of the anal is about equidistant from middle of eye and base of caudal, the modified portion rather short, not nearly reaching base of caudal, its structure as in G. episcopi; ventral fins reaching to or slightly past vent in the female and well past the origin of the anal in the male; pectoral fins reaching a little past base of ventrals, 1.2 to 1.5 in head. Color plain olivaceous; the dark pigment underneath the scales marking the rows of scales, which are so prominent in G. episcopi, is very indistinct in the present species; sides without spots or bars. The tip of dorsal black; anal fin with a black spot at base, which is usually extended on 2 to 5 rays of the fin. Of this species there are numerous specimens in the present collec- tion. The largest female at hand is 62 and the largest male 43 mm. in length. Only a few of our specimens are from the Pacific slope of Pana- ma, and it appears to be comparatively rare in the Rio Chagres Basin, but it is abundant in some small coastal streams at Porto Bello. It was not taken in the Rio Tuyra or Rio Bayano basins. Habitat: Both slopes of Panama, north of the Rio Bayano. 39. Genus Priapichthys Regan. Priapichthys Regan, Proc. Zool. Soc. London, 1913, 991 (type Gambusia annectens Regan). This genus differs from Gambusia in that the modified anal fin of the male is longer, its tip nearly reaching the caudal fin, and it is differently formed; the terminal part is hooked forward and the prolonged rays taper distally and have no specially modified segments, except the usual serrae of the posterior branch of the second; the first prolonged ray does not extend to the apex, and the hook is supported by the anterior branch of the second and third rays. (Regan) Origin of the dorsal fin above the anal. We have tentatively referred one species (P. panamensis} , which does not possess definite antrorse hooks on the intromittent organ, to this genus. KEY TO THE SPECIES. a. First produced ray of intromittent organ with a recurved spur below its apex, directed upward and forward; the apex of this organ curved forward; male with a jet black spot about the size of pupil on sides slightly in advance of vertical from origin of dorsal; dorsal with a dusky spot at base on posterior one-fourth of fin. 320 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. b. Body posteriorly with 6 to 8 dark cross-bars, present in both sexes. tridentiger, p. 320. bb. Body in females plain, no cross-bars, male with very indistinct cross-bars. tridentiger cana, p. 321. aa. First produced ray of intromittent organ without a recurved spur below its apex. c. First produced ray of anal anteriorly serrate below apex, and bearing a hook at apex directed downward and forward, the anterior branch of the second produced ray curved forward at apex; a dark area at base of anterior rays of anal. dariensis, p. 321. cc. Intromittent organ without hooks or serrations, the apex curved forward; a dark area about vent. panamensis sp. nov., p. 322. 57. Priapichthys tridentiger (Carman). Gambusia tridentiger Garman, Mem. Mus. Comp. Zool., XIX, 1895, 89, PI. IV, fig. 10, teeth (Isthmus of Panama) ; Regan, Biol. Cent. Amer., Pisces, 1907, 95. Priapichthys tridentiger Regan, Proc. Zool. Soc. London, 1913, 992. Head 3.55 to 4; depth 3.1 to 5.35; D. 7 or 8; A. 9 or 10; scales 28 to 30. Body compressed; profile straight from snout to nape, then convex to dorsal; head flat above; snout short, 3.75 to 4.3 in head; eye 2.85 to 3.34; interorbital 1.9 to 3; mouth small, cleft reaching about one-third the distance to eye; teeth in jaws pointed, in bands, the outer series somewhat enlarged; scales moderate, cycloid, extending forward to eyes; caudal peduncle strongly compressed, its least depth 1.45 to 2 in head; origin of dorsal in female over the posterior rays of the anal and about equidistant from posterior margin of eye and tip of caudal, or slightly nearer the former, in the male its origin is about midway between posterior margin of eye and base of caudal; caudal fin rounded; anal fin in female inserted somewhat nearer base of caudal than posterior margin of eye, its posterior margin concave at least in large examples; in the adult male the anal fin is inserted notably nearer tip of snout than base of caudal, the longest produced ray failing to reach base of caudal by about an eye's diameter, 2 to 2.3 in length of body; the apex of the intromittent organ curved forward, the first produced ray with a spur a short distance below its apex which is directed downward and forward; ventral fins rather small, reaching vent in female, and past origin of anal in the male; pectoral fins reaching slightly past base of ventrals, 1.2 to 1.9 in head. Color of female olivaceous; scales with pale margins, next to the margins is a dark area formed by dusky points; sides of caudal portion DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 321 of body, i.e., from anal fin backward, with from 6 to 8 dark cross-bars; a dark line from last anal ray to base of caudal; a dark area at base of anterior rays of anal, not extending on fin; posterior rays of anal with a dusky spot near middle and another at tips; dorsal with a dusky spot on posterior one-fourth near base of rays. Color of male very similar, but the cross-bars less distinct, and a jet black spot about the size of the pupil present on side slightly in advance of vertical from origin of dorsal; FIG. 6. DISTAL PART OF INTROMITTENT ORGAN OF Priapichtkys iridtntigv (Gannan). (Greatly magnified.) no dark spot at base of anterior rays of anal. Specimens from Taboga Island paler with the cross-bars less distinct in both sexes. Of this species we have numerous specimens from both slopes of Panama, but none from the Rio Tuyra Basin. The largest female is 45 and the largest male 20 mm. in length. Habitat: Both slopes of Panama, and Taboga Island. 58. Priapichthys tridentiger cana (Meek & Hildebrand). Gambusia cana Meek & Hildebrand, Field. Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 87 (Rio Satiganti, Cana, Panama). Head 3.8 to 4.25; depth 3.2 to 4.35; D. 7 or 8; A. 10; scales 29 to 31. This variety agrees with P. tridentiger in all respects, except in color. In the female there are no dark cross-bars on posterior part of body. In the male the characteristic dark spot of P. tridentiger on side above the base of anal is present, but the cross-bars are less distinct. This form is represented by 68 specimens from the Rio Satiganti, one of the upper tributaries of the Rio Tuyra. The largest female is 40 and the largest male 23 mm. in length. 59. Priapichthys dariensis (Meek & Hildebrand). Gambusia dariensis Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 88 (Rio Capeti). Head 3.4 to 4.1 5; depth 3. 4 to 4. 5; D. 7or8; A.9ono; scales 28to3i. Body moderately compressed; dorsal profile straight over head, slightly convex from nape to dorsal; head flat above; snout short, 3.3 to 4.15 in head; eye 3 to 4.35; interorbital 2.2 to 2.4; mouth small, the gape 322 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. reaching about one-third the distance to eye; teeth in the jaws pointed, in narrow bands, the outer ones somewhat enlarged; scales moderate, cycloid, extending forward to the eyes; caudal peduncle strongly com- pressed, its least depth 1.4 to 1.7 in head; origin of dorsal in female just behind base of last ray of anal and about equidistant from posterior margin of eye and tip of caudal or slightly nearer the latter; in the male this fin is somewhat nearer posterior margin of eye than tip of caudal; caudal fin rounded; anal fin in the female inserted about equidistant from posterior margin of eye and base of caudal, its posterior margin nearly straight; in the adult male this fin is inserted a little nearer tip of snout than base of caudal, the longest modified ray 2.6 to 2.7 in body; the first ray strongly serrate, with a hook at apex directed downward and forward, the anterior branch of second produced ray curved for- ward, the second branch shorter; ventral fins rather small, reaching origin of anal in female and past this point in male; pectoral fins i.i to 1.4 in head. Color of female plain olivaceous; scales on back and upper part of sides with dark punctulations; no black spot on sides or on fins; a dark area at base of anterior ray of anal, and a dark line from anal fin to base FIG. 7. DISTAL PART OF INTROMITTENT ORGAN OF Priapictukys daritnsis (Meek & Hildebrand). (Greatly magnified.) of caudal. The male with a variable number (often as many as 20) of narrow, dark cross-bars on sides; otherwise essentially as in females. There are over 100 specimens of this species in the present collection. The largest female is 36 and the largest male 27 mm. in length. This species was taken in the Rio Juan Diaz, Rio Bayano, and Rio Tuyra basins. 60. Priapichthys panamensis sp. nov. Type No. 8950, F. M. N. H.; length 24 mm.; Chame Point, Panama. Head 3.55 to 4; depth 3.65 to 4.3; D. 8; A. 10; scales 29 to 31. Body moderately compressed; profile very gently convex from snout to origin of dorsal; head broad, flat above; snout short, 3.75 to 4.5 in head; eye 2.65 to 3.3; interorbital 1.75 to 2.4; mouth small, the cleft DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 323 reaching about one-third the distance to eye; teeth pointed, in bands in the jaws, the outer ones slightly enlarged; scales moderate, cycloid, ex- tending to tip of snout and on base of caudal; caudal peduncle strongly compressed, its least depth 1.5 to 1.8 in head; origin of dorsal in female over base of last ray of anal, and about midway between posterior margin of eye and base of caudal; in the male the origin of the dorsal is about midway between tip of snout and base of caudal; caudal rather pointed; anal fin in female inserted considerably nearer end of snout than tip of caudal, its posterior margin convex; origin of anal in adult male is about half as far from end of snout as from tip of caudal, the produced portion failing to reach base of caudal by about the length of post-orbital part of head, its length 2 to 2.25 in body, the anterior branch of the second produced ray the longest, directed forward at apex, the first produced ray a little longer than the third, no spur; ventral fins reaching to or slightly past vent in female, and notably past origin of anal in male; pectoral fins reaching at least to middle of ventrals, i to 1.4 in head. Color of the sexes similar, grayish green; posterior part of body with 4 or 5 indistinct, dark cross-bars; a dark line from anal to base of FIG. 8. DISTAL PART OF INTROMITTENT ORGAN OF Prioptchthys panamensis sp. nov. (Greatly magnified.) caudal; dorsal fin with dark chromatophores at base of the posterior rays and again at the tips of these rays; usually with a more or less distinct dark area about vent. Of this species we have 37 specimens. The largest female is 37 and the largest male 24 mm. in length. One specimen is from the Rio Chame and all the others from a brackish pool at Chame Point on the Pacific coast. In general appearance this fish resembles Priapichihys tridentiger, but the intromittent organ of the male is quite different, the caudal fin is more pointed and bears more scales on its base, the color is paler, and the cross-bars are fewer. Type a male 24 mm. in length, from Chame Point. 324 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 40. Genus Poeciliopsis Regan. Pceciliopsis Regan, Proc. Zool. Soc. London, 1913, 996 (type Pcecilia •presidionis Jordan & Culver). Body elongate, compressed; head more or less depressed; mouth small, the cleft transverse; teeth in the jaws in 2 series or bands, de- pressable, the outer ones largest, slightly compressed; the intromittent organ long and slender, without hooks or serrations at apex; ventral fins not modified in the male. KEY TO THE SPECIES. a. The three produced rays of anal, as well as both branches of the second, all of about equal length and reaching to apex of intro- mittent organ, failing quite notably to reach base of caudal when deflexed; no dark area over vent; young of 60 mm. and less in length with dark cross-bars on posterior part of body; fins un- marked, elongatus, p. 324. aa. The first and the anterior branch of the second produced ray of anal fin in male of about equal length and extending to apex of intromittent organ, the posterior branch of the second and the third produced ray notably shorter; intromittent organ when deflexed reaching nearly or quite to base of caudal; a dark area over vent; indistinct cross-bars on body; fins dusky, the dorsal with blackish basal band and dark edge. isihmensis, p. 325. 61. Poeciliopsis elongatus (Gunther). Pcecilia elongata Gunther, Cat. Fish. Brit. Mus., VI, 1866, 342 (Panama), and Trans. Zool. Soc. London, VI, 1869, 484, PL LXXXV, fig. 2 (Panama); Jordan & Evermann, Bull. U. S. Nat. Mus., XL VII, 1896, 697; Gilbert & Starks, Mem. Cal. Ac. Sci., 1904, 50 (Brackish sloughs about Panama) ; Regan, Biol. Cent. Amer., Pisces, 1907, 102. Mollienisia elongata Regan, Proc. Zool. Soc. London, 1913, 1013 (Panama). ?Heterandria colombianus Eigenmann & Henn, Indiana Univ. Studies, No. 16, 1912, 27 (Rio Dagua, Colombia); Regan, Proc. Zool. Soc. London, 1913, 996. ?P&ciliopsis colombianus Henn, Ann. Carnegie Mus., X, 1916, 120 (Rio Dagua, Colombia). Head 3.4 to 4.4; depth 3.4 to 4; D. 8 to 10, usually 9; A. 8 or 9; scales 28 to 33. Body elongate, robust, posteriorly compressed; head depressed, flat above; snout broad, 3.8 to 4.55 in head; eye 3.33 to 4.6; interorbital 2 to 2.2; mouth transverse; teeth in outer series close-set, slightly com- DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 325 pressed or pointed, curved inward, this series is followed by a narrow band of minute teeth; scales large, cycloid, 8 or 9 rows between base of dorsal and anal; origin of dorsal in female variable, usually about midway between end of snout and tip of caudal, and posterior to vertical from origin of anal ; its origin in the male is at about the same point as in female, but the fin is higher; caudal fin scaly at base, its margin rounded; anal fin in female usually inserted about midway between tip of snout and base of caudal; anal fin in adult male inserted nearer end of snout than base of caudal, the modified portion very long, slender, more or less needle-shaped, 2.35 to 2.7 in length; ventral fins similar in both sexes, usually failing to reach vent in large females, reaching oppo- site base of anal in males; pectoral fins moderate, i to 1.25 in head. Color of sexes similar, olivaceous. Large specimens without cross- bars; young of 60 mm. and less in length with narrow, dark cross-bars on posterior portion of sides. Fins unmarked. Of this species we have 80 specimens. The largest female is 150 and the largest male 60 mm. in length. It was taken by us only in brackish water about the city of Panama where it is fairly common. FIG. 9. DISTAL PART OF INTROMITTENT ORGAN OF Pcstiiiopsis elongatus (Gunther). (Greatly magnified.) We have examined 2 female specimens, paratypes, of P. colombianus (Eigenmann & Henn). We do not find that they differ essentially from the present species. However, in the absence of male specimens of the former their identity with P. elongatus remains doubtful. Habitat: Pacific coast of Panama and probably of Colombia. 62. Pceciliopsis isthmensis Regan. Paeciliopsis isthmensis Regan, Proc. Zool. Soc. London, 1913, 997 (Colon, Panama). Head 3.5 to 3.7; depth 2.5 to 3; D. 9 or 10; A. 10; scales 26 to 28. Body robust; mouth small; teeth in narrow bands; interorbital width 1.8 to 2 in head; eye 3 to 3.2; origin of dorsal fin midway between anterior margin of the eye and base of caudal, its longest ray 1.5 in head; origin of anal below fourth or fifth ray of dorsal, its first branched ray 1.3 in head; pectoral a little shorter than the head; least depth of caudal peduncle 1.3 to 1.5 in head; in the male the origin of the dorsal is 326 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. midway between the tip of the snout and base of caudal, or nearer the former; the modified anal reaching quite to caudal fin. Color olivaceous, scales dark edged; a blackish spot above the vent; fins dusky, the dorsal with a blackish basal band and a dark edge. The male with indistinct cross-bars on the body. Females 35 to 60 mm. in length; males 35 to 42. This species was not taken by us at Colon. It is probably identical with the species described by Meek* as Peecilia pittieri from Costa Rica. 41. Genus Mollienisia LeSueur. Mollienisia LeSueur, Jour. Acad. Nat. Sci. Phila., 1821, 3, PI. Ill (type Mollienisia latipinna LeSueur). Body oblong to rather robust; mouth small, transverse, with weak jaws; teeth small, in bands, the outer series in each jaw movable; branchiostegals 5; anal fin of female slightly in advance to slightly behind dorsal; dorsal fin of males often very high; dorsal fin of 7 to 1 6 rays; anal fin of male modified into an intromittent organ, the first prolonged ray bearing a small antrorse spine at or near its end, the last ray bearing a process directed outward and towards the base of the fin; intestinal canal long and with numerous convolutions; vertebrae about KEY TO THE SPECIES. a. Dorsal fin with 7 to 1 1 rays. b. Origin of dorsal slightly in advance of anal. c. Dorsal fin with 10 or n rays; anal with 10 rays; dorsal and caudal fins spotted with black. sphenops, p. 326. cc. Dorsal fin with 7 or 8 rays; anal fin with 8 or 9 rays; dorsal fin with a dark spot on its base, the rest of dorsal and caudal fin unspotted. caucana, p. 329. bb. Origin of dorsal slightly behind that of anal; dorsal and caudal with a series of transverse spots. cuneata, p. 329. aa. Dorsal rays n to 13; origin of dorsal a little nearer base of caudal than end of snout. formosa, p. 330. 63. Mollienisia sphenops (Cuvier & Valenciennes). Paribiba. Pcecilia sphenops Cuvier & Valenciennes, Hist. Nat. Poiss., XVIII, 1846, 130, PI. 526 (Vera Cruz, Mexico); Gtinther, Cat. Fish. Brit. Mus., VI, 1866, 343 (Vera Cruz, Mexico); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 694; Regan, Biol. Cent. Amer., Pisces, 1907, 102 (Streams near Panama). *Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1912, 71. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 327 Xiphophorus gillii Kner & Steindachner, Abhandl. K. Bayer. Ak. Wiss. Munchen, X, 1864, 28, PI. IV, fig. i (Rio Chagres, Panama). Platypcecilus mentalis Gill, Proc. Ac. Nat. Sci. Phila., 1876, 335 (Panama) ; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 686. Pcecilia boucardi Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXVI, 1878, 386, PI. Ill, figs. 2 & 3 (Colon, Panama) ; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 695; Gilbert & Starks, Mem. Cal. Acad. Sci., 1904, 51 (Streams near Panama). Pcecilia gillii Garman, Mem. Mus. Comp. Zool., XIX, 1895, 63 (Panama). Mollienisia sphenops Regan, Proc. Zool. Soc. London, 1913, 1012, fig. 173, F (in part); Henn, Ann. Carnegie Mus., X, 1916, 136 (Carta- gena, Colombia). Head 3. 15 to 4; depth 2.65 to 3. 75; D. ioor n; A. 10; scales 27 to 30. Body compressed; head depressed, flat above; snout broad, its length 3.2 to 4 in head; eye 3.1 to 3.9; interorbital 1.85 to 2.4; mouth small, the cleft transverse; teeth in the outer series slender, movable, somewhat broadened and hooked at apex; inner teeth in a band, small, tricuspid; scales moderate, cycloid, 8 longitudinal rows between base of dorsal and anal; origin of dorsal in female a little in advance of anal, and somewhat nearer end of snout than tip of caudal, its base about equal to length of longest rays; in the male this fin is much higher and the base is equal to about two-thirds the length of the longest rays; caudal fin scaly at base, its margin rounded; anal fin in female inserted about equidistant from end of snout and tip of caudal, the anterior rays not produced; in the male this fin is inserted equidistant from end of snout and base of caudal, the produced portion 1.2 to 1.45 in head, the first and the two branches of the second produced ray of about equal length, the anterior ray bearing a small antrorse hook at apex, the third with a process directed downward and backward at its apex; in advance of the intromittent organ lies a sort of hood which is not attached to the distal portion of this organ; ventral fins normal in the female, reaching vent; in the male the first articulated ray is produced, reaching notably beyond base of anal; pectoral fins rather long, 1.05 to 1.7 in head. Color olivaceous, dorsal and caudal fins with dark dots. The color of specimens from salt and brackish water is more variable than those taken in fresh water. The markings on Atlantic slope specimens are more distinct than on those from the Pacific side. The color markings of specimens from Colon agree with those from Vera Cruz, Mexico; most of the specimens have a black spot on each scale forming lines along the rows. These spots are seldom present on the Pacific side specimens and when present are not very distinct. The males often have 328 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. X. the basal half of the dorsal and caudal fins black, the distal half of the latter often yellow, a condition not conspicuous on west coast specimens. The fresh water individuals are much more uniform in color, and usually smaller than those from salt and brackish water. Those taken from fresh water might be regarded as a variety under the name Mol- lienisia sphenops gillii (Kner & Steindachner). This species is represented by numerous specimens in the present collection. The largest females are 100 and the largest males 78 mm. in length. It occurs abundantly in quiet ponds and arms of the rivers and creeks of both slopes of Panama, but not in the Rio Tuyra Basin. The males of this species are so large that they are pretty certainly caught along with the females and do not escape through the meshes of the net, as has been stated of other viviparous species of this family, in explanation of the small number of male specimens occurring in col- lections. For this reason we have counted 2,142 specimens collected at various points and on various dates during two periods of the two years during which these collections were made. Among this number there are 579 males or nearly 3.7 females to every male. The disparity of males to females is, however, believed, in reality, to be greater than these figures indicate, for this species was many times taken in such abundance that only a small number of them was preserved. In such FIG. 10. DISTAL PART OF INTROMITTENT ORGAN OF M oUUnisia spkenops (Cuvier & Valenciennes). (Greatly magnified.) cases, due to the fact that the males are more brightly colored and thus more conspicuous, it is quite probable that more than their proportion- ate number was selected, although we do not remember that any par- ticular attention was given to this matter at the time. Habitat: Coasts and rivers from Sinaloa, Mexico, both slopes of Panama, south to eastern Colombia, Venezuela and the Leeward Islands. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 329 64. Mollienisia caucana (Steindachner). Girardinus caucanus Steindachner, Denkschr. K. Ak; Wiss. Wien, XLII, 1880, 87, PI. VI, figs. 4 & 5 (Caceres, Colombia), and Denkschr. K. Ak. Wiss. Wien, LXXII, 1902, 146 (Baranquilla, Colombia). P cecilia caucana Regan, Biol. Cent. Amer., Pisces, 1908, 190. Mollienisia sphenops Regan, Proc. Zool. Soc. London, 1913, 1012 (in part). Head 3.35 to 3.7; depth 3.6 to 4; D. 7 or 8; A. 8 or 9; scales 28 to 30. Body compressed; head slightly depressed, flat above; snout rather broad, 3.2 to 4.4 in head; eye 3 to 3.75; interorbital 2.3 to 2.7; mouth small, the cleft transverse; teeth and scales as in preceding species; origin of dorsal in female over origin of anal, a little nearer end of snout than tip of caudal; slightly more anteriorly situated in male; caudal fin scaly at base, the margin rounded; anal fin in female inserted a little nearer end of snout than tip of caudal; in the male this fin is inserted somewhat nearer end of snout than base of caudal, the modified portion usually about equal to length of head, its structure apparently identical with that of the preceding species; ventral fins in females reaching vent, the outer ray produced in males, reaching beyond base of anal; pectoral fins moderate, 1.2 to 1.66 in head. Color of the sexes similar, olivaceous; dorsal fin with a dark blotch at base of the middle rays; fins otherwise unmarked. This species is represented by 22 specimens in the present collection. The largest female is 35 and the largest male 30 mm. in length. It was taken by us at only two places, Aruza and Cituro, in the Rio Tuyra Basin. This is the only species of Mollienisia collected in that river basin. This species is apparently closely related to M. sphenops, but differs in color, and in the number of dorsal and anal rays. Habitat: Pacific slope of southeastern Panama and the eastern slope of Colombia. 65. Mollienisia cuneata (Carman). Pcecilia cuneata Garman, Mem. Mus. Comp. Zool., XIX, 1895, 62, PI. V, fig. 3 (Turbo, Gulf of Darien). Head 4; D. 8 to 10; A. 9 or 10; scales 28 or 29. Body short and deep; caudal peduncle deep; head depressed, broad and flat; snout as long as eye; mouth wide, the jaws weak and loosely joined; outer series of teeth slender, oar-shaped, movable; inner bands small, pointed; eye half interorbital space, its length 3^ in head; origin of dorsal over third ray of anal, midway from base of caudal to head: 330 FIELD MUSEUM OP NATURAL HISTORY — ZOOLOGY, VOL. X. anal of female small, its third ray the longest; modified anal of male shorter than the head; ventrals small, not reaching anal; caudal deep, its posterior margin rounded. Color brownish, bases of scales dark; dorsal region dark, the ventral region silvery; dorsal with one to several transverse series of small spots of black, the fin sometimes black tipped; caudal with small spots of black on basal half, or with a couple of clouded transverse bands; the fins uniform or punctulate. (Garman.) This species was not seen by us. 66. Mollienisia formosa (Girard). Limia formosa Girard, Proc. Ac. Nat. Sci. Phila., 1859, 115 (Palo Alto, Mexico). Mollienisia formosa Gunther, Cat. Fish. Brit. Mus., VI, 1866, 349; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 699; Regan, Proc. Zool. Soc. Lond., 1913, 1012 (Tampico, Mexico; Colon, Panama). Head 3.3 to 4; depth 2.5 to 3; D. u to 14; A. 9 or 10; scales 26 to 28. Body rather robust; eye 3 to 3.5 in head; interorbital 1.7 to 2; origin of dorsal a little nearer the base of caudal than the end of the snout; origin of anal below fourth ray of dorsal; pectoral shorter than the head; caudal fin rounded; least depth of caudal peduncle, 1.3 to 1.6 in head; modified anal of male 1.3 in head. Color olivaceous; scales with brown spots; dorsal fin with transverse series of blackish spots, other fins plain. This species is recorded from Colon by Regan. It does not occur in our collections. Habitat: Atlantic slope of Mexico and Central America. 42. Genus Rivulus Poey. Rivulus Poey, Memorias, II, 1858, 307 & 383 (type Rivulus cylindraceus Poey). Cynodonichthys Meek, Field Col. Mus. Pub., Zool Ser., V, 1904, 101 (type Cynodonichthys tenuis Meek). Slender fishes with subterete body; mouth small, the branches of the lower jaw firmly united; teeth conical, in bands, the outer ones enlarged and curved; one or two teeth on each side usually enlarged and canine- like; margin of eyes not free; pectorals obtuse, low; caudal rounded or subtruncate; dorsal small, over posterior part of the much longer anal; oviparous; air bladder large; alimentary canal short, about % to & length of body. DEC. 28, 1916. FISHES OP PANAMA — MEEK AND HILDEBKAND. 331 KEY TO THE SPECIES. a. Dorsal fin with 7 rays; anal with n or 12 rays; depth 5 to 6 in length. elegans, p. 331. aa. Dorsal fin with 9 or 10 rays; anal with 13 or 14 rays; depth 4.35 to 4.9 in length. brunneus, p. 331. 67. Rivulus elegans Steindachner. Rivulus elegans Steindachner, Denkschr. K. Ak. Wiss. Wien, XLII, 1880, 85, PI. VI, fig. 6 (Rio Cauca) ; Regan, Ann. & Mag. Nat. Hist., Ser. 8, X, 1912, 498 (Rio Condoto, Colombia), and Ann. & Mag. Nat. Hist., Ser. 8, X, 1913, 471; Henn, Ann. Carnegie Mus., X, 1916, 108 (Rio Condoto and Rio Truando, Colombia). Head 3.33 to 3.85; depth 5 to 6; D. 7; A. n or 12; scales 33 to 35. Body long, slender, posteriorly compressed; head depressed, wider than deep; snout broad, 3.5 to 4.3 in head; eye 3 to 3.75; interorbital broad, 2.15 to 2.6; mouth rather small, oblique; lower jaw projecting; teeth in the jaws in bands, the outer ones enlarged, curved inward; scales cycloid, with prominent circulae, 7 or 8 longitudinal rows of scalps between base of dorsal and anal; origin of dorsal over posterior one- fourth of anal, and about midway between gill-opening and tip of caudal or slightly nearer the former, the base of the last ray a little behind vertical from base of last anal ray; caudal fin strongly rounded; anal fin inserted notably nearer tip of caudal than tip of snout, the length of its base scarcely equal to the greatest width of head; ventral fins small, about as long as diameter of eye, reaching origin of anal; pectoral fins moderate, not reaching base of ventrals, 1.3 to 1.8 in head. Color brownish, sides more or less speckled with dark spots. Most of our specimens with a dark ocellus at base of upper rays of caudal; lower lobe of caudal with or without a black stripe extending from under side of caudal peduncle to end of caudal rays, forming an intramarginal bar. Dorsal and anal more or less dusky. There are 22 specimens in the present collection, ranging in length from 26 to 38 mm. All were taken in small brooks near the water shed on the Atlantic slope at Culebra. R. elegans is very probably identical with R. godmani Regan. Habitat: Panama, south to Colombia. 68. Rivulus brunneus Meek & Hildebrand. Rivulus brunneus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 86 (Toro Point, Canal Zone, Panama). Head 3.3 to 3.7; depth 4.35 to 4.9; D. 10, rarely 9; A. 13 or 14, rarely 12; scales 34 to 38. 332 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Body rather robust, posteriorly compressed; head depressed, wider than deep; snout short, 3.65 to 4.25 in head; eye 3.2 to 3.8; interorbital 2.2 to 2.65; mouth small, the cleft scarcely lateral; teeth pointed, in bands in the jaws, the outer ones somewhat enlarged, curved inward; scales rather small, cycloid, the circulse strongly developed; 8 longitu- dinal rows of scales between base of dorsal and base of anal; origin of dorsal over middle of base of anal or slightly posterior to this point, and somewhat nearer tip of caudal than posterior margin of eye, the base of its last ray slightly behind vertical from base of last ray of anal; caudal fin rounded; anal fin inserted midway between the tip of snout and tip of caudal or slightly nearer the former, its margin convex, the length of the base equal to the greatest width of head; ventral fins small, about as long as diameter of eye, reaching vent; pectoral fins moderate, failing quite notably to reach base of ventrals, 1.6 to 1.8 in head. Color brownish, sides more or less speckled with darker; dorsal and caudal with or without faint, dark spots; a black stripe from under side of caudal peduncle to end of caudal rays usually present, forming an intramarginal bar; on some specimens there is a similar bar on the upper lobe of the caudal fin, although less distinct. In life the upper parts of the body are grayish with shades of pink, and the belly is pale and also has a shade of pink. The fins are all reddish, and the base of caudal and anal are deep red. Of this species we have 17 specimens, ranging in length from 35 to 50 mm. All are from the upper course of a small creek at Toro Point. Order IV. Acanthopterygii. THE SPINY-RAYED FISHES. Spines normally present in the anterior part of the dorsal and anal fins; border of the mouth formed by the premaxillary; ventral fins usually thoracic; anterior vertebrae unmodified; opercular bones all present. Family IX. Mugilidae. Body elongate, more or less compressed; mouth small, terminal or inferior; teeth, if present, small, various in form; premaxillaries pro- tractile; gill-openings wide, the membranes free from the isthmus; gill-rakers usually long and slender; gills 4, a slit behind the fourth; DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 333 lateral line usually absent, never complete; scales large, extending forward on head; dorsal fins 2, well separated, the first composed of 4 rather strong spines; second dorsal with one spine and from 7 to 10 soft rays; caudal fin forked; anal fin with 2 or 3 spines and 7 to n soft rays; ventral fins abdominal, each with one spine and 5 branched rays; pectoral fins placed high. The genera Agonostomus and Joturus comprise fresh water species and are dealt with in the present paper. The marine species of this family will be discussed in another work. KEY TO THE GENERA. a. Snout scarcely in advance of upper lip; teeth in lower jaw in a continuous band; dorsal spines rounded, not prominently com- pressed. Agonostomus, p. 333. aa. Snout projecting beyond upper lip; teeth in lower jaw in two lateral patches, not confluent anteriorly; dorsal spines notably compressed. Joturus, p. 336. 43. Genus Agonostomus Bennett. Agonostomus Bennett, Proc. Comm. Zool. Soc., I, 1831, 166 (type Agonostomus telfairii Bennett). Neomugil Valliant, Bull. Soc. Philom. Paris, IV, 1894, 73 (type Neomugil digueti Valliant.) Body elongate, compressed; mouth terminal in young, subinferior in adult, the cleft extending laterally to or past front of eye, the lower lip not greatly thickened; teeth in bands on jaws, vomer and palatines, those on jaws with lance-shaped apices or serrated margins; first dorsal with 4 rounded spines; anal spines 2, the first one minute, often hidden in the skin; stomach not gizzard-shaped. Inhabiting tropical rivers, some of them living in mountain torrents. The American species of this genus have been described in current works as having pointed teeth in the jaws. This is certainly not true of the specimens at hand, either from Panama or Cuba. The outer series in each jaw is mostly composed of lance-shaped teeth and the inner ones nearly all have a serrated margin. KEY TO THE SPECIES. a. Body comparatively slender, the depth 3.7 to 3.85 in its length in specimens about 150 mm. long; mouth rather small, the maxil- lary reaching to or slightly past vertical from anterior margin of eye. monticola, p. 334. 334 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. aa. Body somewhat deeper, the depth 3.1 to 3.3 in length in speci- mens about 150 mm. long; mouth large, the maxillary reaching nearly to vertical from middle of eye. macracanthus, p. 335. 69. Agonostomus monticola (Bancroft). Mugil monticola Bancroft, in Griffith's Edition Cuvier's Animal King- dom, Fishes, 1836, 367, PI. 36 (West Indies). Agonostoma monticola Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 464 (West Indies). Agonostoma nasutum Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 463 (Rio San Geronimo, Guatemala), and Trans. Zool. Soc. London, 1868, 444, PI. 70, fig. i. Neomugil digueti Valliant, Bull. Soc. Philom., IV, 1894, 73 (Lower California). Agonostomus monticola Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 819, fig. 347; Regan, Biol. Cent. Amer., Pisces, 1907, 66; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 118 (both slopes of Costa Rica). Agonostomus nasutus Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 819; Regan, Biol. Cent. Amer., Pisces, 1907, 68, PI. X, fig. 4. Head 3. 4 to 4.1; depth 3.1 to 4.1; D. IV-1, 8; A. II, 10; scales 39 to 43. Body compressed; upper profile gently convex; head rather small; snout conical, 3.2 to 4.1 in head; eye 3 to 4.9; interorbital 2.85 to 3.4; mouth moderate, nearly horizontal; upper jaw somewhat in advance of the lower; upper lip various, thin, moderately thick, or very thick, its upper margin elevated or not at tip of snout; maxillary reaching to or a little past vertical from anterior margin of eye, 2.6 to 3.2 in head; teeth in bands on jaws, vomer and palatines, the jaw teeth mostly with serrate margins, some with lance-shaped apices; gill-rakers rather short, 17 to 20 on lower limb of first arch; scales rather large, ctenoid, extend- ing forward to interorbital area, about 1 2 rows between anterior rays of second dorsal and anal; origin of first dorsal notably nearer tip of snout than base of second dorsal, the anterior 2 spines of equal length poste- riorly when deflexed, the first one somewhat longer than eye and snout; origin of second dorsal nearer origin of the first dorsal than base of caudal, the outer margin of the fin concave; caudal fin with small scales on basal half, moderately forked; anal fin similar to second dorsal, but a little longer, its origin slightly in advance of second dorsal, with 2 spines, the first one minute and hidden in the skin in adult ; ventral fins inserted under middle of pectorals, a little nearer origin of anal than tip of snout; pectoral fins placed high, of about the same length as ventrals, 1.32 to 1.5 in head. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 335 Color bluish black above; sides mostly silvery, the margin of scales brown; pale below. Very young often with a dark lateral band, which later becomes only faintly visible. A dark caudal spot present at all ages, but most distinct in young. The spines of first dorsal black, the membranes yellowish green; second dorsal and caudal yellowish green at base; ventrals yellow; pectorals plain translucent. Very young some- times with reddish fins. There are 118 specimens, ranging from 40 to 255 mm. in length, in the present collection which we have identified as this species. These were collected at various points on both slopes of Panama, mostly in the lowland streams, some even were taken in brackish water, and a few are from upland streams. On the Atlantic slope it was taken at several points in the Chagres Basin and in small coastal streams at Porto Bello and Toro Point. On the Pacific slope it was found everywhere, except in the Rio Tuyra Basin. After careful study of our material, together with specimens from Cuba and Guatemala, we find it impossible to retain the two nominal species, A. monticola and A. nasutus. The only reason for keeping the two separate heretofore apparently was the alleged difference in the thickness of the upper lip. We, however, find that in our large series this is a variable character upon which no reliance can be placed. We have specimens with a thin upper lip, some with a thick lip, and nearly all stages between. These occur indiscriminately on both slopes, and in the same rivers and pools. However, the thick-lipped form occurs more frequently among our Pacific slope specimens than among those from the Atlantic. Habitat: Mexico; Central America; both slopes of Panama and the West Indies. 70. Agonostomus macracanthus Regan. Agonostomus macracanthus Regan, Ann. & Mag. Nat. Hist., Ser. 7, XIX, 1907, 65, and Biol. Cent. Amer., Pisces, 1907, 69, PI. XI, fig. i (Rio Guacalate, Guatemala). Head 3.4 to 3.55; depth 3.1 to 3.3; D. IV-I, 8; A. II, 12; scales 41 to 42. Body compressed, rather deep; head low; snout conical; 3.25 to 3.55 in head; eye 4.34 to 4.9; interorbital 3.05 to 3.25; mouth rather large, slightly oblique; the upper jaw projecting; the upper lip quite thick; maxillary reaching nearly to vertical from middle of eye, 2.44 to 2.6 in head; teeth as in preceding species; gill-rakers short, about 20 on lower limb of first arch; scales large, ctenoid, extending forward to inter- orbital region, about 12 rows between anterior rays of second dorsal and 336 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. anal; origin of first dorsal about midway between tip of snout and base of caudal, the first spine equal to or shorter than the second, not longer than eye and snout; origin of second dorsal notably nearer origin of first dorsal than base of caudal, margin of fin concave; caudal fin with small scales on basal half, moderately forked; anal fin similar to second dorsal but a little longer, with 2 spines, the first one minute and often hidden in the skin, its origin under or slightly in advance of second dorsal, midway between base of ventrals and base of caudal; ventral fins inserted under middle of pectoral, somewhat nearer origin of anal than tip of snout; pectoral fins placed high, of about the same length as the ventrals, 1.4 to 1.65 in head. Color bluish black above; sides silvery, with margin of scales brown; pale below. An indefinite dark lateral streak, with a silvery one above it, most evident on posterior part of body; a dark caudal spot present. Spines of first dorsal black, the membranes greenish; second dorsal, caudal and distal half of anal dusky; ventrals and pectorals plain in spirits, except that the upper ray of pectoral is black. There are only 2 specimens of this species in the present collection, respectively 173 and 205 mm. in length. Both specimens were taken at the base of a waterfall near the mouth of the Rio Indio, a tributary of the Upper Chagres. This species differs from the preceding principally in the somewhat deeper body and in the notably larger mouth. Habitat: Rio Guacalate, Guatemala; Rio Chagres, Panama. 44. Genus Joturus Poey. Joturus Poey, Memorias, II, 1861, 263 (type Joturus pichardi Poey). Xenorhynchichthys Regan, Ann. & Mag. Nat. Hist., Ser. 8, II, 1908, 461 (type Joturus stipes Jordan & Gilbert). Snout protruding beyond upper Hp; teeth in lower jaw in two lateral patches which do not meet anteriorly; dorsal spines compressed. In other respects essentially as in Agonostomus. One species known, living at the foot of waterfalls and rapids. 71. Joturus pichardi Poey. Joturus pichardi Poey, Memorias II, 1861, 263 (Cascades throughout Cuba); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 821; Regan, Biol. Cent. Amer., Pisces, 1907, 70; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 117 (both slopes of Costa Rica). Agonostoma globiceps Gunther, Arm. & Mag. Nat. Hist., Ser. 4, XIV, 1874, 370 (Myzantla, Vera Cruz). DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 337 Joturus stipes Jordan & Gilbert, Proc. U. S. Nat. Mus., V, 1882, 373 (Rio Bayano, Panama). Xenorhynchichthys stipes Regan, Ann. & Mag. Nat. Hist., Ser. 8, II, 1908, 461 (Rio Iroquois, Costa Rica). Head 4 to 4.27; depth 3.2 to 3.9; D. IV-I, 9; A. II, n; scales 43 to 45. Body elongate, compressed; the dorsal region somewhat elevated; profile from snout to first dorsal evenly convex; head rather low and broad; snout conical, projecting beyond upper lip, 2.75 to 3.4 in head; eye small, 4 to 6.5; interorbital broad, 1.93 to 2.7; mouth moderate, horizontal, inferior; lower jaw included; maxillary reaching about to vertical from middle of eye, 2.3 to 3.1 in head; teeth in the jaws com- pressed, with serrate margins, those of the upper jaw in a narrow, con- tinuous band, those of the lower jaw in 2 lateral patches, not meeting anteriorly; vomerine teeth in a transverse patch; palatine teeth minute, in a very narrow band; pterygoid teeth, if present, very minute; gill- rakers short, about 30 below angle on first arch; scales large, ctenoid, extending forward to nostrils, 12 to 14 longitudinal rows between base of second dorsal and anal; origin of first dorsal a little nearer base of last ray of second dorsal than tip of snout, the spines notably compressed, the first one reaching slightly past tip of the second when deflexed, equal to about two-thirds length of head; second dorsal, caudal and anal mostly covered with small scales; origin of second dorsal somewhat nearer origin of first than base of caudal, its outer margin concave; caudal fin forked, the lobes of about equal length; anal fin similar to second dorsal, its origin under or slightly in advance of origin of second dorsal, and about midway between base of ventrals and base of caudal; ventral fins inserted under middle of pectorals, about midway between tip of snout and origin of anal; pectoral fins somewhat longer than ventrals, i.i to 1.3 in head. Color in life, of a specimen about 200 mm. in length, very dark green above, with the base of scales green and the margin black; sides lighter green with the margin of the scales brown; pale below. Dorsal fins black at base with broad yellowish green margins; caudal and anal black at base, otherwise irregularly blotched with black and yellow; ventrals and pectorals dark at base and yellowish at tips. The young have two oblique bars on each lobe of the caudal and two similar ones on second dorsal and anal. In large examples these markings completely disappear. We have 26 specimens of this species, ranging from 150 to 460 mm. in length. Most of our specimens were taken by a discharge of dyna- mite below a waterfall near the mouth of the Rio Indio, a tributary of the Upper Chagres. The others were taken by natives with hook and 338 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. line at Gatun, at the "Spill-way," which creates an artificial waterfall. We did not obtain it on the Pacific slope, although it is recorded from the Rio Mamoni. This fish is said to reach a length of one meter and is much valued as food. Habitat: Southern Mexico to Panama and Cuba. Family X. Cichlidae. THE MOJARRAS. Body elongate, compressed, covered with ordinary scales, which are usually ctenoid; lateral line interrupted under soft portion of dorsal, reappearing lower down on caudal peduncle; mouth large or small, terminal to subinferior; teeth conical, incisor-like, or lobate; vomer and palatines without teeth; premaxillaries freely protractile; the maxillary usually slipping under the broad preorbital; nostril single on each side; dorsal fin single, the spinous portion usually longer than the soft portion; gill-membranes usually connected and free from the isthmus; air bladder present; ventral fins I, 5, thoracic; anal fin with 3 or more spines, the soft portion smaller, though similar to that of dorsal; branchiostegals 5 or 6; no pseudobranchiae. A large family of fresh water fishes inhabiting the lowland streams of Mexico and the waters of Central and South America and Africa. Only a few species occur in Panama. KEY TO THE GENERA. a. Anal fin with 3 spines. b. First gill-arch normal, without a lamelliform lobe above angle; snout usually shorter than postorbital part of head. jEquidens, p. 338. bb. First gill-arch with a lamelliform lobe above angle; snout much longer than postorbital part of head. Geophagus, p. 340. aa. Anal fin with more than 3 spines. c. Teeth all conical. Cichlasoma, p. 342. cc. The outer series of teeth in both jaws compressed, incisor-like. Neetroplus, p. 348. 45. Genus /Equidens Eigenmann & Bray. jEquidens Eigenmann & Bray, Ann. N. Y. Ac. Sci., VII, 1894, 616 (type Acara tetramerus Heckel). DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 339 Body robust, compressed; mouth small, the premaxillary not greatly protractile; gill-rakers minute; margin of lower lip free at sides; teeth conical, none of them canine-like; anal spines 3; upper portion of anterior gill-arch without a lamelliform lobe. This genus contains a large number of species which inhabit the waters of South America, one species only occurring as far north as Panama. 72. /Equidens coeruleopunctatus (Kner & Steindachner). Acara coeruleopunctata Kner & Steindachner, Sitzungsb. K. Bayer. Ak. Wiss. Munchen, 1863, 222, and Abhandl. K. Bayer. Ak. Wiss. Munchen, X, 1864, 16, PI. II, fig. 3 (Rio Chagres, Isthmus of Panama); Gunther, Trans. Zool. Soc. London, VI, 1869, 449 (Rio Chagres); Steindachner, Denkschr. K. Ak. Wiss Wien, XLI, 1880, 56 (Rio Cauca); Regan, Ann. & Mag. Nat. Hist., Ser. 7, XV, 1905, 336, and Biol. Cent. Amer., Pisces, 1906, 16 (Rio Chagres, Panama; N. W. Ecuador). Mquidens coeruleopunctatus Eigenmann & Bray, Ann. N. Y. Ac. Sci., VII, 1894, 616; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 1514. Head 2.6 to 2.78; depth 2 to 2.3; D. XIV or XV, 9 to n; A. Ill, 7 or 8. Body robust; anterior profile strongly convex; head short and heavy; snout blunt, 2.53 to 3.8 in head; eye 3 to 4.45; interorbital much broader than eye, except in very young; preorbital broader than eye in large examples, but notably narrower than eye in young; mouth ter- minal, rather small; the maxillary failing to reach eye, 3.1 to 3.8 in head; lips not thickened, the margin of lower lip free at sides only; teeth in the jaws conical, forming a band in each jaw; gill-membranes broadly con- nected across isthmus; gill-rakers short, about 8 on lower arm of first arch; lateral line interrupted under anterior rays of soft portion of dorsal, reappearing on third row below its original course; scales rather large, cycloid, i>£ to 2 rows between lateral line and middle of base of dorsal; dorsal fin long, its origin over posterior margin of opercle, the spines rather short and strong, the last one 2.2 to 3.3 in head, the soft portion much elevated in large examples, the produced rays often reaching nearly to tip of caudal, none of the rays much produced in the young and not reaching far beyond base of caudal; caudal fin scaly at base, its margin convex; anal fin with 3 strong spines, the soft portion similar to that of dorsal; ventral fins inserted a little behind base of pectorals, reaching origin of anal in young, a few of the rays produced in adult reaching oppo- site the soft portion of anal; pectoral fins rather long, .97 to 1.15 in head. 340 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Color in life of a large example: Back bluish black, pale brownish below; sides with 4 indistinct cross-bars, a dark blotch on sides below last half of spinous portion of dorsal; cheeks with 2 distinct blue-green lines and numerous spots of the same color; these spots are also present on sides and breast; base of caudal with a large black spot. Dorsal fin bluish black, the soft rays with a tinge of deep red and with a yellow margin; caudal fin reddish blue with darker spots; anal fin dark blue, the last rays reddish at tips; ventral fins slate; pectorals greenish. The dark cross-bars on sides more numerous and more distinct in young. Cheeks, sides and chest without blue-green lines or spots; fins all paler and without red. Considerable variation in color is evident among our specimens. Individuals taken in muddy streams are much duller, and do not possess any blue-green lines and spots. Of this species there are numerous specimens in the present col- lection, ranging in length from 2 5 to 1 5 7 mm. One of the most abundant species in the streams of Panama, occurring on both slopes, from tide water to the highest mountain streams. Habitat: Both slopes of Panama and south to Colombia, and Ecuador. 46. Genus Geophagus Heckel. Geophagus Heckel, Ann. Wiener Mus., II, 1840, 383 (type Geophagus altifrons Heckel = Sparus surinamensis Bloch). Satanoperca Gunther, Cat. Fish. Brit. Mus., IV, 1862, 312 (type Geopha- gus acuticeps Heckel). Body oblong, compressed; mouth moderate; jaws with conical teeth; premaxillary moderately protractile; outer gill-arch with a com- pressed lamelliform lobe above, gill-rakers at or near its margin; margin of lower lip not free at its middle; caudal fin emarginate to slightly forked; anal spines 3. One species of this genus is known to occur in Panama, its range not extending northward far beyond the Canal Zone. 73. Geophagus crassilabris Steindachner. Geophagus (Satanoperca} crassilabris Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXIV, 1876, 65, PI. VII (Vicinity of Candelaria, Isthmus of Panama). Satanoperca crassilabris Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 1542. Geophagus crassilabris Pellegrin, fitude Pois. Fam. Cichlides, Lille, 1904, 160 (Isthmus of Panama) ; Regan, Biol. Cent. Amer., Pisces, 1906, 16. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 341 Head 2.46 to 3.13; depth 2.35 to 2.95; D. XVI, 9 or 10; A. Ill, 7 or 8; scales 29 to 31. Body rather deep, compressed; the back elevated; anterior profile distinctly convex in young, straight in adults not possessing a nuchal hump, concave in specimens with nuchal hump; head deep; snout long and pointed in adult, much shorter and more blunt in young, equal to half length of head in specimens about 125 mm. in length, much greater than half length of head in large specimens and much shorter than half head in very young, 1.6 to 4 in head in specimens ranging from 30 to 263 mm. in length; eye circular, placed high, lower margin of pupil about on level with upper angle of gill-opening, 2.95 to 5.85 in head; preorbital broad, about 2 times diameter of eye in large examples, equal to or a little less than diameter of eye in very young; mouth moderate, hori- zontal; maxillary failing to reach anterior margin of eye, 2.6 to 3.65 in head; jaws equal or the upper slightly projecting; the lips thickened, the lower with a fleshy lobe on each side; teeth conical, in bands in each jaw; gill-membranes broadly connected across isthmus; gill-rakers short, about 13 on lower limb of first arch; lateral line interrupted under soft portion of dorsal, reappearing on the third row of scales below its original course; scales of moderate size, feebly ctenoid, from 2 to 3^ rows between lateral line and middle of base of dorsal; dorsal fin long, its origin over posterior margin of opercle, the spines rather short and strong, the last one 2.7 to 3.3 in head, the soft portion varying greatly in length among different individuals, usually reaching base of caudal, a few of the rays occasionally produced and reaching far beyond this point; caudal fin scaly at base, its margin concave; anal fin short, the spines strong, the soft portion similar to that of dorsal; ventral fins inserted slightly behind base of pectorals, reaching to or past vent; pectoral fins moderate, 1.2 to 1.5 in head. Color in life greenish brown above, yellowish below. Sides in young with well defined black cross-bars, these less distinct in adult; very young also with a black lateral band. Lips and gill-membranes blue in adult. Dorsal, caudal, anal and ventrals reddish yellow in adult, more greenish in young; pectorals greenish. This fish is represented by numerous specimens, ranging from 30 to 263 mm. in length. It is common in the streams on both slopes of Panama. There is considerable variation with respect to the development of the soft portion of the dorsal and anal fins and the number of rows of scales between the lateral line and base of dorsal, but our large series is ample to show that these are only individual variations. Habitat: Isthmus of Panama. 342 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 47. Genus Cichlasoma Swainson. Cichlasoma Swainson, Nat. Hist. Class. Fishes, Amph. and Rept., II, 1839, 230 (type Sciana bimaculata Linnaeus). Theraps Gunther, Cat. Fish. Brit. Mus., IV, 1862, 284 (type Theraps irregularis Gunther). Parapetenia Regan, Ann. & Mag. Nat. Hist., Ser. 7, XVI, 1905, 324 (type Acara adspersa Gunther). Body ovate to oblong, compressed; mouth rather small to large; premaxillary moderately protractile, the maxillary slipping under the preorbital; fold of the lower lip continuous or not; teeth conical, to slightly compressed in a few species; a few anterior teeth canine-like in species with large mouths; anal spines IV to XI. To this genus belong many species, some are deep, others more or less elongate. In many of the species the mouth is small, the gape horizontal or nearly so, and the anterior teeth conical to slightly com- pressed. In others the mouth is terminal, oblique, and with some of the anterior teeth enlarged and canine-like. The efforts to break this group into several genera or subgenera have not met with much success, since the characters on which they have been based are too variable and overlap. Only five species are known to occur in central and eastern Panama. KEY TO THE SPECIES. a. The outer series of teeth in the jaws somewhat enlarged, and regularly increased in size anteriorly; mouth small or moderate; the maxillary not reaching past vertical from anterior margin of eye. b. Lower lip narrow, its margin not free at symphasis; teeth all sharply pointed. c. A large black blotch present at base of caudal, and usually with another large black blotch on sides under tips of pectorals; sides without distinct cross-bars; lateral band present only in very young; scales in lateral series 31 to 33; lower lateral line on third row of scales below upper lateral line. maculicauda, p. 343. cc. Young with cross-bars; adults with a single series of black blotches along middle of sides; spot at base of caudal com- paratively small; black dots on rows of scales, forming dark lines; scales in lateral series 34 to 41; lower lateral line present on fifth row of scales below upper lateral line; 6 or 7 rows of scales between lateral line and base of anterior dorsal spines; anal with 6 or 7 spines. tuyrense, p. 344. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 343 ccc. Body with cross-bars, forming a series of blotches on upper lateral line and a larger series on middle of sides; each scale with a dark spot; scales in lateral series 30 to 32 ; 4 rows of scales between lateral line and base of anterior dorsal spines; anal spines 5. .sieboldii, p. 345. bb. Lower lip broad, continuous, and free at symphasis; teeth rather blunt; young with dark cross-bars, these less distinct in adult; sides with a large, black blotch under posterior part of spinous portion of dorsal; a small black spot at base of upper half of caudal. calobrense, p. 346. aa. The anterior pair of teeth in each jaw enlarged; mouth rather large; the maxillary reaching past vertical from anterior margin of eye; sides with a dark lateral band, ending in a jet black caudal spot. umbriferum, p. 347. 74. Gichlasoma maculicauda Regan. Cichlasoma maculicaiida Regan, Ann. & Mag. Nat. Hist., Ser. 7, XVI, 1905, 227 (Lake Yzabal and Rio Motagua, Guatemala; Rio Chagres, Panama), and Biol. Cent. Amer., Pisces, 1906, 19, PI. II, fig. 3. Head 2.7 to 3.23; depth 1.75 to 2.1; D. XVII or XVIII, n or 12; A. VI, 9 or 10; scales 31 to 33. Body deep, compressed; anterior profile a little concave in large specimens possessing a slight nuchal hump, convex in others; head deep; snout moderate, 2.1 to 4 in head; eye 2.8 to 4.3; mouth small, terminal, slightly oblique; maxillary failing to reach anterior margin of eye, 3.4 to 4 in head; the lips not thickened, the lower one not free at middle; teeth in the jaws pointed, in 2 more or less definite series, the outer and anterior ones enlarged; gill-membranes united across isthmus; gill- rakers short, about 9 or 10 on lower limb of first arch; scales moderate, ctenoid, 5 or 6 rows between lateral line and middle of base of dorsal; lateral line interrupted under soft portion of dorsal, reappearing on the third row of scales below its original course; origin of dorsal over or slightly in advance of base of pectoral, the spines strong, the last one 1.8 to 2.5 in head, the soft portion pointed, a few of the rays somewhat produced in large examples, always reaching notably past base of cau- dal, its base with small scales; caudal fin scaly at base, its margin con- vex, more strongly so in adult than in young; anal fin with 6 strong spines, the soft portion similar to that of dorsal; the outer rays of the ventral fins somewhat produced, reaching to or past origin of anal; pectoral fins moderate, 1.14 to 1.3 in head. Color yellowish-green to brownish, without distinct cross-bars. Lateral band present only in young (25 mm.), which also have a black 344 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. band at base of dorsal. A large black blotch present at base of caudal, and most specimens with a black blotch on middle of side under tip of pectoral. An occasional specimen also has many small dark spots on sides. Fins plain translucent, or dusky; the vertical fins often with small dark spots. There are 237 specimens, ranging from 20 to 250 mm. in length, in the present collection. All are from the lower Chagres and its tribu- taries. It was frequently found abundant in very brackish water, and in Panama its range seems to be limited to the brackish and sluggish streams of the Atlantic slope. The parents appear to guard their young for quite some time after hatching. On one occasion it was noticed that two large fishes, evidently of this species, were hovering very closely to numerous small ones, at a place where the water was quite shallow. An attempt was made to surround them with a seine. However, the adults by their very quick movement made their escape. A large number of young was taken. Only a few minutes after the seine was hauled the two large fishes reap- peared and a second attempt at capturing them failed. The young were all of about equal size, ranging from 20 to 24 mm. in length. Habitat: Lake Yzabal, Guatemala, south to Rio Chagres, Panama. 75. Cichlasoma tuyrense Meek & Hildebrand. Heros margaritifer var. Steindachner, Denksch. K. Ak. Wiss. Wien, XLI, 1879, 161 (Rio Mamoni, Chepo). Cichlasoma tuyrense Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 89 (Rio Tuyra, Boca de Cupe, Panama). Head 2.75 to 3.45; depth 1.77 to 2.1; D. XVI to XVIII, usually XVII, ii or 12; A. VI or rarely VII, 8 or 9; scales 34 to 41. Body deep, compressed; anterior profile nearly straight in young, strongly convex in adult; no nuchal hump; head deep; snout moderately pointed, 2.2 to 3.4 in head; eye 3.33 to 4.3; mouth rather small, terminal, slightly oblique; maxillary failing to reach anterior margin of eye, 2.8 to 3.7 in head; the lips not thickened, the lower one not free at middle; teeth in the jaws pointed, in bands, the outer one somewhat enlarged; gill-membranes broadly connected across isthmus; gill-rakers short, about 8 on lower limb of first arch; scales rather small, weakly ctenoid, 6 or 7 rows between lateral line and middle of base of dorsal; lateral line interrupted under soft portion of dorsal, reappearing on the fifth row of scales below its original course; origin of dorsal over posterior margin of opercle, the spines strong, the last one 1.86 to 2.33 in head; the soft portion with small scales at base, pointed and reaching well past base of caudal in adult; caudal fin scaly at base, its posterior margin strongly 08 o g 3 2 5fe g O DEC. 28,1916. FISHES or PANAMA — MEEK AND HILDEBRAND. 345 convex; anal with 6 or 7 strong spines, the soft portion similar to that of dorsal; ventral fins more or less produced, reaching to or past origin of anal; pectoral fins equal to or slightly shorter than head. Color brownish; sides in young with dark cross-bars as wide as interspaces, in adult with a series of black blotches along median line of sides; black dots on rows of scales forming dark lines, these most distinct in large examples. Base of caudal with a short black bar or spot; the vertical fins usually with dark spots; ventral fins dusky. This species is represented by 114 specimens, ranging from 29 to 300 mm. in length. It was taken only in the Rio Bayano and Rio Tuyra basins. Our largest specimen sometime during its career had the lower lobe of the caudal fin broken off at its base. The fin regenerated and again formed normal rays, except that at the time of capture they had not grown as long as the uninjured portion. This species probably resembles C. sieboldii (Kner & Steindachner). The last named species was based on specimens from the west slope of Panama. Our fish, however, differs so notably in several respects from the species as described that we are unable to identify our specimens with it. The body in the present species is slightly deeper; eye larger; scales in lateral line more numerous; last dorsal spine is notably longer; the pectoral fin is longer; the caudal fin is always notably rounded; and there is a single series of black blotches placed along middle of side and none on upper lateral line. Habitat: Rio Bayano and Rio Tuyra basins. 76. Cichlasoma sieboldii (Kner & Steindachner). Heros sieboldii Kner & Steindachner, Abhandl. K. Bayer. Ak. Wiss. Munchen, X, 1864, 13, PI. II, fig. 2 (New Grenada, west slope, Panama). Cichlasoma sieboldii Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 1516; Regan, Ann. & Mag. Nat. Hist., Ser. 7, XVI, 1905, 235. "Depth of body about 2% in length, length of head about $%. Snout as long as postorbital part of head. Diameter of eye 4-5 in length of head and 1^2—2^2 in interorbital width. Maxillary not extending to below eye; jaws equal anteriorly, fold of lower lip not continuous; cheek with 5 series of scales; 8 or 9 gill-rakers on lower part of anterior arch. Scales 30-32, 4/13, 2^2 between lateral line and base of anterior part of soft dorsal. Dorsal XVII n, the spines increasing in length to the last, which is about ^ the length of head; soft fin, when laid back, extending nearly to middle of caudal. Anal V, 8. Pectoral y^A the length of head; ventral extending to the vent. Caudal sub- 346 FIELD MUSEUM OF NATURAL HISTORY — ZOSLOGY, VOL. X. truncate or slightly rounded. Caudal peduncle about 4/s as long as deep. Reddish brown, each scale with a dark spot; 5 or 6 dark cross-bars form- ing a series of blotches on the upper lateral line and a second larger series on the middle of the side; vertical fins dark greyish with series of blackish spots." (Regan.) This species was not seen by us. The above description is an exact copy from Regan, Annals and Magazine of Natural History, Ser. 7, Vol. XVI, 1905, p. 235. If the type of this species actually came from Panama, it is rather singular that it was not obtained there by us. C. tuyrense is more closely related to this species than any other taken by us, but there are such important differences that it is scarcely possible that the two are confused. Habitat: Pacific slope of Panama. 77. Cichlasoma calobrense Meek & Hildebrand. Cichlasoma calobrense Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 90 (Rio Calobre, Panama). Head 2.73 to 2.9; depth 2.13 to 2.7; D. XVII, 10 to 12; A. VI, 7 or 8; scales 28 to 31. Body moderately elongate, compressed; head deep; snout tapering, longer than postorbital part of head (except in young less than 55 mm. in length), 1.87 to 2.75 in head; eye 3.1 to 4.58; mouth moderate, ter- minal, nearly horizontal; maxillary reaching vertical from anterior margin of eye, 2.5 to 3.3 in head; the lips large, the lower one broad, continuous and free at middle; teeth in the jaws bluntly conical, the outer ones somewhat enlarged, and with brown tips; gill-membranes con- nected across isthmus; gill-rakers short, about n or 12 on lower limb of first arch; scales rather large, feebly ctenoid, 3 or 4 rows between lateral line and middle of base of dorsal; lateral line interrupted under soft portion of dorsal, reappearing on third row of scales below its original course and usually considerably in advance of end of upper lateral line; origin of dorsal over posterior margin of opercle, the spines strong, graduated, the last one 2.2 to 3 in head; the soft portion with only a few scales at base on interradial membranes, the middle rays somewhat produced, reaching well beyond base of caudal; caudal fin with scales on basal half, its margin always convex; anal fin with 6 strong graduated spines, the soft portion similar to that of dorsal; ventral fins rather long and pointed, the longest rays reaching opposite second or third anal spine; pectoral fins not quite reaching origin of anal, i.i 8 to 1.47 in head. Color brownish. Young with dark cross-bars and a more or less distinct dark lateral band; the dark bars less distinct in adult, and the £ S O .5 < CD s M K c •o '£ " P S E 5 c 3 ec _ E E ' en fc. < &. I O O DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 347 lateral band wanting. A large black blotch on middle of side, under posterior part of spinous portion of dorsal; a small black caudal spot at base of upper half of caudal; cheeks, opercle and anterior portion of sides often with small rusty spots. Vertical fins sometimes with small dark spots; ventral and anal fins usually bluish black. We have 69 specimens of this species, ranging from 33 to 212 mm. in length. These are from the Rio Bayano and Rio Tuyra basins. 78. Cichlasoma umbriferum Meek & Hildebrand. Cichlasoma umbriferum Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 88 (Rio Cupe, Cituro, Panama). Head 2.5 to 2.83; depth 2.2 to 2.5; D. XVI or XVII, n or 12; A. VI, 8 or 9; scales 30 to 32. Body moderately elongate; anterior profile nearly straight, and oblique; head rather large; snout tapering, a little shorter than post- orbital part of head, 2.8 to 3.2 in head; eye 3.4 to 4.7; mouth moderate, terminal, slightly oblique; maxillary reaching nearly or quite to vertical from anterior margin of pupil, 2 to 2.25 in head; the lips not notably thickened, the lower one of moderate width, continuous and free at middle; teeth in the jaws pointed, the anterior pair in each jaw somewhat enlarged; gill-membranes connected across isthmus; gill-rakers short, about 9 on lower limb of first arch; scales rather large, ctenoid, 5 or 6 rows between lateral line and middle of base of dorsal; lateral line in- terrupted under soft portion of dorsal, reappearing on third row of scales below its original course; origin of dorsal over or slightly in advance of posterior margin of opercle; the spines rather strong, gradu- ated, the last one 2.65 to 3.65 in head; the soft portion with a sheath of scales at base and with small scales on interradial membranes, the rays not much produced, not reaching very far beyond base of caudal ; lower half of caudal fin rather densely scaled, the margin strongly convex; anal fin with 6 strong, graduated spines, the soft portion similar to that of dorsal ; ventral fins inserted slightly behind base of pectorals, a few of the rays somewhat produced and reaching a little past origin of anal; pectoral fins moderate, not reaching tips of ventrals, 1.3 to 1.52 in head. Color from light brown to bluish black; sides without cross-bars, except in young up to 50 mm.; a dark lateral band, extending from eye to upper half of base of caudal, ending in a jet black caudal spot; lower part of sides often with bluish spots, these most evident on light colored specimens. Vertical fins with dark and bluish spots; ventral fins bluish black; pectoral fins plain translucent. We have 40 specimens of this species, ranging from 28 to 236 mm. in length. All are from the Rio Tuyra Basin. 348 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. X. 48. Genus Neetroplus Gunther. Neetroplus Gunther, Trans. Zool. Soc. London, VI, 1869, 469 (type Neetroplus nematopus Gunther). Body ovate to elongate, compressed ; mouth small ; the anterior teeth in each jaw compressed and incisor-like. In other respects like Cichlasoma. This genus contains three species, one each in Nicaragua, Costa Rica, and Panama. 79. Neetroplus panamensis Meek & Hildebrand. Neetroplus panamensis Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1913, 90 (Rio Mandingo, Bas Obispo, Canal Zone, Panama). Head 2.9 to 3.1; depth 2 to 2.25; D. XVII (rarely XVIII), 9 or 10; A. VI (rarely VII), 7; scales 27 to 30. Body rather short, compressed; head moderate; snout blunt, equal to or shorter than postorbital part of head, 2.4 to 3 in head; eye 3 to 3.84; mouth small, terminal; maxillary failing to reach anterior margin of eye, 3.25 to 3.75 in head; cheeks with 3 rows of rather large scales; lips thin, the lower one free only at sides; teeth in the jaws distinctly compressed, incisor-like, with reddish brown tips; gill-membranes broadly connected across isthmus; gill-rakers short, 7 or 8 on lower limb of first arch; scales moderate, ctenoid, 2^ to 3 rows between lateral line and middle of base of dorsal; lateral line interrupted under soft portion of dorsal, reappearing on third row of scales below its original course; origin of dorsal over margin of opercle, the spines graduated, the last one 2.3 to 2.8 in head; the soft portion scaly at base, pointed, a few of the middle rays produced, reaching to distal fourth of caudal; caudal fin scaly at base, its margin evenly convex; anal fin with 6 or rarely 7 strong, graduated spines, the soft portion similar to that of dorsal; ventral fins with the outer rays produced, often reaching opposite the 4th or 5th anal spine; pectoral fins not quite reaching origin of anal, i.i to 1.24 in head. Back bluish black; sides reddish or brownish. Young with black- ish bars, these obscure or wanting in adult; a prominent dark blotch on middle of sides below posterior portion of spinous dorsal, and sometimes with a series of irregular black blotches on lower part of side from above base of pectorals to base of caudal; vertical fins dark, tinged with red in adult; ventral fins always pale blue. There are 42 specimens, ranging from 65 to 103 mm. in length, in the present collection. Habitat: Rio Chagres Basin. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 349 Family XL Gobiidae. Body oblong or elongate; teeth various, usually small; premaxillaries protractile; gill-openings usually rather small, the membranes attached to the isthmus; opercle unarmed; preopercle unarmed or with a short spine; orbital margin not free, continuous with skin of head; lateral line wanting; scales present or wanting; dorsal fins 2, separate or connected, the first composed of 2 to 8 slender spines; the second dorsal preceded by a single weak spine; margin of caudal fin convex; anal usually similar to second dorsal; ventral fins close together, separate or united, when united forming a sucking disc, consisting of I, 5 or rarely of I, 4 rays, in- serted under base of pectorals; pectoral fins with a broad sub vertical base. Most of the representatives of this family are marine, but some of them enter fresh water and rivers. Only the latter of the Panama species are discussed in the present paper. KEY TO THE GENERA. a. Ventral fins separate. b. Vomer with villiform teeth; gill-openings extending forward to below eyes. Philypnus, p. 350. bb. Vomerine teeth wanting; gill-openings not extending forward to below eyes. c. Head very broad; eyes lateral; jaws anteriorly of equal length; teeth compressed at apices; gill-rakers numerous, well developed, in 2 series on each arch. Intestinal canal long; species herbi- verous. Dormitator, p. 353. cc. Head narrower; eyes lateral or not; lower jaw more or less pro- jecting; teeth all pointed; gill-rakers few, poorly developed. Intestinal canal short; species carniverous. d. Preopercle with a small, sharp, concealed spine at its lower poste- rior angle. Eleotris, p. 356. dd. Preopercle unarmed. e. Scales very small, 100 or more in a lateral series. Guavina, p. 360. ee. Scales larger, usually fewer than 40 in a lateral series. f. Dentary bones broad, expanded, meeting under posterior angle of mouth, leaving an oval-shaped, naked patch at chin. Leptophilypnus gen. nov., p. 361. ff . Dentary bones narrow, not nearly meeting under posterior angle of mouth. g. Head broad depressed; eyes superior; head and chest naked. Microeleotris gen. nov., p. 362. 3So FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. gg. Head compressed; eyes lateral; head (with the exception of snout) and chest scaly. Hemieleotris gen. nov., p. 364. aa. Ventral fins united, forming a sucking disc. h. Teeth in the jaws in narrow bands; ventral disc longer than wide, free from abdomen; shoulder girdle with 2 or more dermal flaps projecting into gill-cavity. Awaous, p. 365. hh. Teeth in upper jaw in a single, close-set series, slender, tricuspid, bicuspid or simple, curved inward; lower jaw with 2 series of teeth, the outer series nearly horizontal, partly or completely hidden in the gums, second series erect, pointed; ventral disc circular, more or less adnate to abdomen; no dermal flaps on shoulder girdle. Sicydium, p. 369. 49. Genus Philypnus Cuvier & Valenciennes. Philypnus Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 255 (type Gobiomorus dormitor Lacepede). Lembus Gunther, Cat. Fish. Brit. Mus., I, 1859, 505 (type Lembus maculatus Gunther). Body elongate, anteriorly subcylindrical, posteriorly compressed; head more or less depressed above; mouth large; lower jaw projecting; teeth small, in bands on jaws and on vomer; gill-opening large, extending forward to under eye; scales rather small, ctenoid, covering body and most of head; dorsal fins 2, well separated, with VI-I, 9 rays; caudal fin rounded; anal fin with I, 9 or I, 10 rays. This genus consists of but two species, both of which usually inhabit lowland streams. KEY TO THE SPECIES. a. Scales small, 61 to 64 in lateral series from upper angle of gill- opening to base of caudal; anal rays I, 9; vertical fins with rather large black spots, forming cross-bars. dormitor, p. 350. aa. Scales larger, 56 to 59 in lateral series; anal rays I, 10; vertical fins with small and less distinct blackish spots. maculatus, p. 352. 80. Philypnus dormitor (Lacepede). Gobiomorus dormitor Lacepede, Hist. Nat. Poiss., II, 1798, 599 (Mar- tinique, from a drawing by Plumier); Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 482. Platycephalus dormitator Bloch, Syst. Ichthyol., 1801, PI. 60, t. 12 (Mar- tinique). Ekotris dormitatrix Cuvier, Regne Animal., Ed. 2, II, 1829, 246; Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 119. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 351 Philypnus dormitator Cuvier & Valenciennes, Hist. Nat. Poiss., XII, J837, 255; Poey, Memorias, II, 1860, 381; Regan, Biol. Cent. Amer., Pisces, 1906, 5. Eleotris longiceps Gunther, Proc. Zool. Soc. London, 1864, 151 (Nicaragua). Philypnus dormitor Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2194; Meek, Field Col. Mus. Pub., Zool. Ser., V, 1904, 226 (Mexico), and Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 129 (Atlantic slope of Costa Rica). Head 3.2 to 4.3 ; depth 4.65 to 6.2 ; D. VI-1, 9; A. I, 9; scales 61 to 64. Body elongate, nearly as wide as deep anteriorly, compressed poste- riorly; head long, somewhat depressed, its width at preopercular margin 1.55 to 2.3 in its length; the cheeks rounded; snout long, depressed, 2.95 to 3.6 in head; eye 4.75 to 7.8; interorbital 3.7 to 6.65; mouth large, oblique; lower jaw projecting; maxillary reaching middle of eye, 2.05 to 2.5 in head; teeth small, pointed, all depressable except the outer ones, in bands on jaws and on vomer; gill-rakers undeveloped; gill-arches with small, elevated patches of pointed teeth; lateral line wanting; scales small, ctenoid; origin of spinous dorsal about an eye's diameter behind base of pectorals, the spines weak and rather variable in length, but never reaching origin of soft dorsal when deflexed; origin of soft dorsal an eye's diameter in advance of origin of anal, the margin convex; caudal fin scaly at base, its margin rounded; anal fin similar to soft dorsal; ventral fins inserted slightly behind base of pectorals, rather short, not nearly reaching vent; pectoral fins reaching to or beyond tips of ven- trals, 1.53 to 1.74 in head. Color brownish. Young with a dark lateral band, becoming more obscure with age. Back and sides often with marbling of dark brown, and sometimes with dark bars. Fins all more or less reddish in life. The dorsals, caudal, and usually the pectorals and anal with rather large dusky spots, so arranged as to form cross-bars. In the present collections there are 118 specimens, ranging from 40 to 359 mm. in length. It is most common in the brackish and fresh waters of the lowland streams, but stragglers occur in the upper courses of the Chagres and its tributaries. It usually inhabits shallow water where it lies quietly among the vegetation, presumably in wait for its prey. The alimentary canal is short, and without blind sacs. It feeds on crustaceans, fishes, water beetles and apparently any other aquatic animal life of suitable size. In Panama it is of little importance as a food fish. Habitat: Atlantic coast streams, from Texas south to Brazil, and the West Indian Islands. FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 81. Philypnus macula tus (Gunther). Lembus maculatus Gunther, Cat. Fish. Brit. Mus., I, 1859, 505 (Andes of Ecuador). Philypnus lateralis Gill, Proc. Ac. Nat. Sci. Phila., 1860, 123 (Cape San Lucas); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2195 (Rio Presidio, Mazatlan). Ekotris lateralis Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 122 (Cape San Lucas). Eleotris lembus Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 121 (Western Ecuador). Gobiomorus lateralis Eigenmann & Fordice, Proc. Ac. Nat. Sci. Phila., 1885, 69. Gobiomorus maculatus Eigenmann & Fordice, Proc. Ac. Nat. Sci. Phila., 1885, 70. Philypnus maculatus Regan, Biol. Cent. Amer., Pisces, 1906, 5; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 130 (Pacific slope of Costa Rica). Head 2.75 to 3.6; depth 4.25 to 5; D. VI-I, 9; A. 1, 10 or rarely I, n ; scales 56 to 59. Body elongate; not much deeper than wide anteriorly, compressed posteriorly; head long, somewhat depressed, its width at preopercular margin 1.73 to 2.2 in its length; cheeks nearly vertical; snout long, depressed, 2.86 to 3.4 in head; eye 4.35 to 7.25; interorbital 3.95 to 6; mouth large, oblique; lower jaw projecting; maxillary reaching middle of eye, 2.2 to 2.4 in head; teeth small, pointed, all depressable except the outer ones, in bands on jaws and on vomer; gill-rakers undeveloped; gill-arches with small, elevated patches of pointed teeth; lateral line wanting; scales a little larger than in preceding species, ctenoid; origin of spinous dorsal about an eye's diameter behind base of pectorals, the spines weak and variable in length, sometimes reaching origin of soft dorsal when deflexed; origin of soft dorsal an eye's diameter in advance of origin of anal, the rays variable in length, the margin convex; caudal fin scaly at base, its margin rounded; anal fin similar to soft dorsal; ventral fins inserted slightly behind base of pectorals, rather short, failing to reach vent; pectoral fins reaching to or past tips of ventrals, 1.4 to 1.84 in head. Color brownish. Young with a dark lateral band or blotches along side, the blotches usually persisting. Fins with much red in life; the dorsals, caudal and usually the anal with dusky spots, which are, how- ever, notably smaller and less distinct than in the preceding species; pectoral fins without spots or bars. There are 425 specimens in the present collection, ranging from 40 DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 353 to 290 mm. in length. This fish is abundant in all the lowland streams of the Pacific slope of Panama. In this region it is more abundant than its Atlantic congener. What is stated regarding the habits of the foregoing species applies equally as well to the present species. This fish is closely related to its Atlantic slope congener, from which it can, however, be readily separated by the larger scales, by the con- stant presence of one more ray in the anal fin and by the smaller and less distinct dark spots on the vertical fins. The body is also slightly deeper anteriorly and the head is narrower. Habitat: Pacific slope streams from Lower California south to Ecuador. 50. Genus Dormitator Gill. Prochilus Cuvier, R£gne Animal, Ed. i, II, 1817, 294 (type Sciana macrolepidota Bloch =S«#no maculata Bloch). (Name preoccupied.) Dormitator Gill, Proc. Ac. Nat. Sci. Phila., 1862, 240 (type Eleotris gund- lachi Poey—Sciana maculata Bloch). Body elongate, compressed; head broad, flat above; interorbital broad; snout obtuse; mouth moderate, oblique; the jaws anteriorly of equal length; teeth in jaws small, in bands, with compressed tips, none on vomer; gill-openings extending forward to margin of preopercle; gill-rakers well developed, numerous, each arch bearing 2 series; scales present on entire body, upper surface of head, snout and on cheeks and opercles; dorsal fins 2, well separated, the first with 7 feeble spines; caudal fin rounded; ventral fins close together, but separate, with I, 5 rays. The vertical fins notably higher in males than in females. This genus, as here understood, consists of two closely related species, which, owing to a great deal of variation among individuals, can scarcely be separated. KEY TO THE SPECIES. a. Snout short and very broad, its length 4 to 4.35 in head in speci- mens from 60 to 80 mm. in length; mouth very oblique, margin of upper jaw usually slightly above level of lower margin of eye; scales 31 to 35, usually 33, in lateral series, 8 to n longitudinal rows between anterior part of base of second dorsal and anal; ventral fins long, reaching to or past vent, 1.04 to 1.43 in head; pectoral fins reaching vertical from origin of anal, i to 1.23 in head. maculatus, p. 354. aa. Snout slightly longer and somewhat narrower, 3.85 to 4.2 in head in specimens 60 to 80 mm. in length; mouth somewhat less oblique, margin of upper jaw on or below level of lower margin of eye; scales 34 to 37, usually 35, in lateral series, n or 12 longitu- 354 FIELD MUSEUM OP NATURAL HISTORY — ZOOLOGY, VOL. X. dinal series between anterior part of base of second dorsal and anal; ventral fins rather short, failing to reach vent, 1.55 to 1.9 in head; pectorals scarcely reaching vertical from vent, 1.3 to 1.45 in head. latifrons, p. 355. 82. Dormitator macula tus (Bloch). Sciasna maculata Bloch, Naturgesch. der Ausland. Fische, 1790, PI. 299, fig. 2 (West Indies). Eleotris mugiloides Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 226 (Martinique; Surinam). tEleotris grandisquama Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 229 (America, — locality unknown); Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 113. Eleotris sima Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 232 (Vera Cruz). Eleotris somnokntus Girard, Proc. Ac. Nat. Sci. Phila., 1858, 169 (near mouth of Rio Grande). Eleotris omocyaneus Peey, Memorias, II, 1860, 269 (Havana). Eleotris gundlachi Poey, Memorias, II, 1860, 272 (Cuba). Eleotris maculata (in part) Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 112 (Trinidad; Demerara; Surinam). Dormitator lineatus Gill, Proc. Ac. Nat. Sci. Phila., 1863, 271 (Savannah). Dormitator gundlachi Poey, Synopsis, 1868, 396 (Cuba). Dormitator omocyaneus Poey, Synopsis, 1868, 396 (Cuba). Dormitator maculatus (in part) Jordan & Gilbert, Bull. U. S. Nat. Mus., XVI, 1883, 632; (in part) Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2196; Regan, Biol. Cent. Amer., Pisces, 1905, 8. Head 2.95 to 3.55; depth 2.8 to 3.34; D. VII-I, 8 or rarely 9; A. I, 10 or rarely n; scales 31 to 35. Body rather robust, compressed; head flat above, its upper profile straight or slightly concave over eyes; snout very short and broad, its length 3.85 to 4.35 in head; eye lateral, 4.2 to 4.8; interorbital broad, 2.3 to 3.2; mouth broad, strongly oblique, margin of upper jaw slightly above level of lower margin of eye; jaws anteriorly of equal length; width of mouth at its posterior angles notably longer than snout; maxil- lary reaching vertical from anterior margin of eye, 2.95 to 3.4 in head; teeth all small, somewhat compressed at tips, in a band in each jaw; gill-membranes attached to the isthmus, the openings extending forward to margin of preopercle; gill-rakers well developed, a double series on each arch, about 45 in anterior series on lower limb of first arch; scales cycloid on upper surface of head, cheeks, chest and predorsal region, elsewhere ctenoid; snout and cheeks completely covered with scales, DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 355 usually 33 in a lateral series (average for 14 specimens 33); 8 to n rows between base of second dorsal and base of anal; origin of first dorsal midway between tip of snout and base of last ray of second dorsal, the spines weak, usually reaching to or past first ray of second dorsal; origin of second dorsal slightly in advance of origin of anal, the rays varying in length, the posterior ones the longest, often reaching base of caudal; caudal fin scaly at base, its margin strongly convex; anal fin similar to second dorsal; ventral fins rather long, reaching vent and sometimes to or past origin of anal, 1.04 to 1.43 in head; pectoral fins long, usually reaching vertical from origin of anal, i to 1.23 in head. Color variable, usually very dark blue above, yellowish green bars below. Young with oblique, yellowish green bars on sides, and often with a more or less distinct dark lateral band. Sides of head with from 2 to 5 dark lines, these sometimes continued on body. Dorsals and sometimes the anal with dark spots forming bars; caudal fin dusky; distal half of anal usually rusty red, the margin white; ventrals and pectorals yellowish green. There are at hand 179 specimens of this species, ranging in length from 35 to 115 mm. Our specimens are all from stagnant brackish ponds and streams. Intestinal canal equal to about twice the length of body; air bladder thin, adnate to the back. Stomach contents, mud, algae and other plant tissue. Habitat: Atlantic coast and rivers from North Carolina to southern Brazil and the West Indies. 83. Dormitator latifrons (Richardson). Eleotris latifrons Richardson, Voyage "Sulphur," Fishes, 1837, 57, PI. 35, figs. 4 & 5 (probably from Pacific coast of Central America). Eleotris maculata (in part) Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 112 (Guayaquil). Dormitator micropthalmus Gill, Proc. Ac. Nat. Sci. Phila., 1863, 170 (Panama). Eleotris maculata (non Bloch) Gunther, Trans. Zool. Soc. London, VI, 1869, 440 (Huamuchal). Dormitator maculatus (non Bloch) Jordan & Gilbert, Proc. U. S. Nat. Mus., IV, 1881, 232 (Cape St. Lucas) ; (in part) Jordan & Gilbert, Bull. U. S. Nat. Mus., XVI, 1883, 632; (in part) Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2196. Dormitator latifrons Eigenmann & Fordice, Proc. Ac. Nat. Sci. Phila., 1885, 72 (Pacific coast of Central America); Regan, Biol. Cent. Amer., Pisces, 1905, 9. 356 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Scarcely distinguishable from D. maculatus. Head 3 to 3.64; depth 2.86 to 3.7; D. VII-I, 8; A. I, 9; scales 34 to 37. Body as in D. maculatus; the snout somewhat longer and narrower, comparing specimens of like size, 2.7 to 4.5 in head; mouth rather less oblique, the margin of upper jaw on or below level of lower margin of eye; width of mouth at its posterior angles not much longer than snout; maxillary scarcely reaching vertical from anterior margin of eye, 3.15 to 3.55 in head; gill-rakers apparently more numerous than in D. macula- tus, about 70 to 90 in anterior series on lower limb of first arch; scales rather small, usually 35 in a lateral series (average for 14 specimens, 35.2+), ii or 12 rows between base of second dorsal and base of anal; fins rather lower than in D. maculatus, ventrals failing to reach vent, 1.55 to 1.9 in head; pectorals scarcely reaching vertical from vent, 1.3 to 1.45 in head. Of this species 71 specimens, ranging in length from 40 to 235 mm., were preserved. It was taken only in the lower courses of streams, seldom far above the head of tide. It was not taken in the Rio Tuyra Basin, but this is very probably due to the fact that little seining was done in the lower parts of this basin. In only one place, the Rio Abaco (a small stagnant, coastal stream), near Panama, was it taken in abun- dance. Habitat: Pacific coast and rivers, from California to Ecuador. 51. Genus Eleotris Bloch & Schneider. Eleotris Gronow, Zooph. Gronov., 1763, 83 (nonbinomial). Eleotris Bloch & Schneider, Syst. Ichth., 1801, 65 (type Gobius pisonis Gmelin). Body elongate, subcylindrical anteriorly, compressed posteriorly; head low, more or less depressed above, mostly covered with scales, which are usually more or less embedded; mouth rather large, oblique; lower jaw projecting; preopercle with a single concealed spine at its lower posterior angle; teeth small, in bands in the jaws, none on vomer; gill-opening not extending forward to under eyes; scales moderate or small; dorsal fins 2, well separated; caudal fin rounded; ventral fins separate. KEY TO THE SPECIES. a. Scales small, 63 to 75 (most frequently 67 to 69) in lateral series, about 22 rows between base of second dorsal and base of anal; color bluish black above; no dark lines along rows of scales; ventral surface of head and body marbled or spotted with light and dark markings. picta, p. 357. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 357 aa. Scales somewhat larger, 59 to 68 (most frequently 64) in a lateral series, about 18 rows between base of second dorsal and base of anal; color brownish, paler below than above; rows of scales everywhere with dark lines; ventral surface of head and body uniform brownish. pisonis, p. 358. aaa. Scales rather large, 44 to 54 in a lateral series, about 12 rows between base of second dorsal and base of anal; color as in E. pisonis. isthmensis sp. nov., p. 359. 84. Eleotris picta Kner & Steindachner. Eleotris picta Kner & Steindachner, Abhandl. K. Bayer. Ak. Wiss. Munchen, X, 1864, 18, PI. Ill, fig. i (Rio Bayano, Panama); Regan, Biol. Cent. Amer., Pisces, 1906, 8. Culius aquidens Jordan & Gilbert, Proc. U. S. Nat. Mus., IV, 1881, 461 (Rio Presidio near Mazatlan). Eleotris pictus Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2201. Head 3 to 3.25; depth 4.45 to 5.55; D. VI-I, 8; A. I, 8; scales 63 toys- Body elongate, subcylindrical anteriorly, compressed posteriorly; head depressed above, the profile concave over eyes; snout rather short and broad, 3.56 to 4.95 in head; eye 5.55 to 8.85; interorbital 3.3 to 5.35: mouth large, oblique; the lower jaw projecting; maxillary not quite reaching posterior margin of eye in young, but reaching past this point in adults; cheeks with small, partly embedded scales, visible only in young; chin, cheeks and snout in young with lines of pores, forming a net work, these visible only in specimens of less than 100 mm. in length; a concealed preopercular spine, directed downward and slightly for- ward; teeth small, pointed, in bands; gill-rakers undeveloped; gill- membranes attached to the isthmus; scales very small (average in lateral series, for 27 specimens, 69—), about 22 longitudinal series between soft dorsal and anal, those on anterior part of body more or less embedded (in very large examples they are more or less embedded over the entire body); scales on sides posteriorly distinctly ctenoid, except in very large specimens, in which they become smoother; origin of first dorsal about midway between end of snout and tips of rays of second dorsal, the spines weak, the longest not much longer than snout; origin of second dorsal about an eye's diameter in advance of origin of anal, the margin of the fin convex; caudal fin with small scales on base, the margin strongly convex; anal fin similar to second dorsal; ventral fins rather small, inserted under base of pectorals; pectoral fins moder- ate, reaching well beyond the tips of the ventrals, 1.36 to 1.77 in head. 3$8 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Color bluish black above, paler below; ventral surface of head and body marbled or spotted with light and dark markings. These mark- ings become obscure in large examples (250 mm. and more in length). No dark lines along the rows of scales. Fins all with dark and pale markings, forming alternating dark and pale bars, these also become obscure and disappear in large individuals. This species is represented by 56 specimens, ranging from 60 to 440 mm. in length. It is common, but not abundant, in the lowland streams on the Pacific coast of Panama eastward to the Rio Bayano, but it was not taken in the Rio Tuyra. The alimentary canal is short, no pyloric cceca; air bladder thin, adnate to the back. One specimen, 370 mm. in length, had swallowed a fish (Philypnus maculatus) 210 mm. in length. The head of this mor- sel was at the vent and partly digested, and the tail was visible in the mouth. This species is closely related to E. pisonis, from which it apparently differs only in the characters mentioned in the key. Habitat: West coast and streams, from California to Panama and Ecuador. 85. Eleotris pisonis (Gmelin). Gobius pisonis Gmelin, Linn. Syst. Nat., 1788, 1206 (based on Eleotris capite plagioplateo Gronow, Mus. Ichth., II, 1757, 168, which in turn was based on A more pixuma Marcgrave & Piso, Hist. Brasil., IV, 1648, 166 (Brazil)). Gobius amorea Walbaum, Artedi Piscium, III, 1792, 205 (based on Eleotris capite plagioplateo Gronow). Eleotris pisonis Schneider, in Bloch's Syst. Ichthyol., 1801, 68; Eigen- mann & Fordice, Proc. Ac. Nat. Sci. Phila., 1885, 75; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2200; Regan, Biol. Cent. Amer., Pisces, 1905, 7. Eleotris gyrinus Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 220, PI. 356 (Martinique; San Domingo; Surinam). Culius perniger Cope, Proc. Am. Phil. Soc., 1870, 473 (Brazil). Culius belizianus Sauvage, Bull. Soc. Philom. Paris, 1879, 55 (Belize; Cayenne). Head 2.9 to 3.23; depth 4.12 to 6; D. VI-I, 8; A. I, 8; scales 59 to 68. Body elongate, anteriorly subcylindrical, posteriorly compressed, a little deeper and somewhat more rubust than in E. picta, this difference being most evident in a comparison of specimens of like size; head some- what depressed above, the profile concave over eyes; snout broad, 3.85 DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 359 to 4.85 in head; eye 5.13 to 6.4; interorbital 3.65 to 6; mouth rather large, oblique; the lower jaw projecting; maxillary scarcely reaching middle of eye in young, reaching past this point in adult, 2.44 to 3.25 in head; cheeks with partly embedded scales; chin, cheeks and snout with rows of pores, forming a net-work, these most distinct in young; a concealed preopercular spine, directed downward and forward; teeth small, pointed, in bands; gill-rakers undeveloped; gill-membranes attached to the isthmus; scales small (average in lateral series, for 16 specimens, 64+), about 18 longitudinal rows between base of second dorsal and anal, those on anterior part of body more or less embedded, but less so than in E. picta; scales on posterior part of body distinctly ctenoid, those on anterior part of body and abdomen smooth; origin of first dorsal midway between end of snout and tips of rays of second dorsal, the spines short and weak, reaching second dorsal when deflexed; origin of second dorsal an eye's diameter in advance of origin of anal; caudal fin with small scales on base, its margin convex; anal fin similar to second dorsal; ventral fins rather small, inserted under base of pectorals; pectoral fins moderate, reaching well beyond tips of ventrals, 1.3 to 1.54 in head. Color rusty brown above, pale brown below; rows of scales every- where with dark lines. Dorsal fins and sometimes the caudal and anal also with dark and yellow spots or bars; pectoral and ventral fins yellow- ish green. This species is represented by 16 specimens, ranging from 45 to 125 mm. in length. It was found in the lower courses of the Rio Chagres and its tributaries, small coastal streams at Porto Bello and in the upper courses of the Rio Trinidad, It is much less abundant and apparently reaches a smaller size in Panama than its Pacific coast congener. It was always found in strictly fresh water. Habitat: Atlantic coast and rivers, from Florida to southern Brazil, and the West Indies. 86. Eleotris isthmensis sp. nov. Type No. 8951, F. M. N. H.; length 85 mm.; Mindi, Canal Zone, Panama. Head 2.85 to 3.25; depth 4.2 to 5.4; D. VI-I, 8; A. I, 8; scales 44 to 54- Body elongate, anteriorly subcylindrical, posteriorly compressed; head somewhat depressed above, the profile slightly concave over eyes; snout broad, 4.1 to 5 in head; eye 4.22 to 5.8; interorbital 3.8 to 5.2; mouth rather large, oblique; the lower jaw projecting; maxillary reach- ing to or past middle of eye, 2.6 to 3.3 in head; cheeks with partly em- 360 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. bedded scales; chin, cheeks and snout with rows of pores, forming a net work, these most distinct in young; a concealed preopercular spine, directed downward and forward; teeth small, pointed, in bands; gill- rakers undeveloped; gill-membranes attached to isthmus; scales rather large (average in lateral series, for 25 specimens, 48—), about 12 longi- tudinal rows of scales between base of second dorsal and anal, all the scales ctenoid, except the small scales in advance of dorsal and on abdo- men; origin of first dorsal midway between end of snout and tips of rays of second dorsal, the spines short and weak, reaching origin of second dorsal; origin of second dorsal an eye's diameter in advance of anal; caudal fin with small scales at base, its margin strongly convex; anal fin similar to second dorsal; ventral fins rather small, inserted under base of pectorals; pectoral fins rather long, reaching well beyond the tips of ventrals, 1.13 to 1.45 in head. Color uniform brownish, somewhat paler below than above. Rows of scales with dark stripes; dorsal fins and caudal and sometimes the anal with light and dark spots or bars; ventrals and pectorals plain dusky brown. We have 57 specimens of this species, ranging from 19 to 85 mm. in length. All are from the lowland streams, ditches and ponds on the Atlantic coast. A few of the specimens were taken in strictly fresh water, but the majority of them are from brackish and salt water. This species differs from E. pisonis principally in the notably larger scales. We have designated as the type a specimen 85 mm. in length from Mindi, Canal Zone. 52. Genus Guavina Bleeker. Guavina Bleeker, Esquisse d'un Syst. Nat. Gobioid., 1874, 302 (type Eleotris guavina Cuvier & Valenciennes). This genus is related to Eleotris, from which it differs in the structure of the skull, the absence of the preopercular spine and in the very small scales, usually 100 or more in a lateral series. 87. Guavina guavina (Cuvier & Valenciennes). Eleotris guavina Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 223 (Martinique); Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 124 (Demerara); Regan, Biol. Cent. Amer., Pisces, 1905, 7. Guavina guavina Eigenmann & Fordice, Proc. Ac. Nat. Sci. Phila., l885> 73; Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 483; Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2198. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 361 Head 3.25 to 3.6; depth 4.65 to 5.5; D. VII-I, 10; A. I, 10; scales 95 to 115. Body subcylindrical anteriorly, compressed posteriorly; head some- what depressed, wider than deep, the upper profile slightly convex; snout blunt, 3.3 to 3.8 in head; eye small, 4.9 to 6.15; interorbital 2.7 to 3.33; mouth rather large, oblique; the lower jaw projecting; maxil- lary reaching a little past middle of eye, 2.22 to 2.35 in head; cheeks and most of head with scales; teeth small, pointed, in bands; gill-rakers little developed; gill-membranes attached to the isthmus; scales very small, those on anterior part of body and head and abdomen smooth, those on posterior part of body ctenoid; origin of first dorsal about mid- way between tip of snout and base of last ray of second dorsal, the spines rather short and weak, reaching nearly or quite to second dorsal; origin of second dorsal about an eye's diameter in advance of origin of anal, the posterior rays reaching nearly or quite to base of caudal; caudal fin short, with small scales at base, its margin rounded; anal fin similar to second dorsal; ventral fins rather small, inserted under base of pectorals; pectoral fins rather short, reaching but little past tips of ventrals, 1.3 to 1.7 in head. Color bluish black above, brownish below. Fins in spirits dusky or black; the dorsals, anal and ventrals all with pale margin. There are 5 specimens, ranging from 105 to 185 mm. in length, in the present collection. These were taken in brackish ditches and creeks at Colon and Toro Point. Habitat: Atlantic coast and rivers from Mexico to Brazil and the West Indies. 53. Leptophilypnus gen. nov. Type Leptophilypnus fluwatilis sp. nov. Body shaped as in Philypnus. The head, chest and predorsal region naked; mouth large, oblique; eyes not wholly lateral; interorbital nar- row; dentary bones meeting under posterior angle of mouth; leaving an oval-shaped naked area at chin; preopercular spine wanting; teeth all small, pointed, in broad bands in the jaws, none on vomer. Gill- opening extending forward nearly to vertical from posterior margin of eye. Readily distinguished from all other Eleolridina by the broad and expanded dentary bones. Carniverous. 88. Leptophilypnus fluviatilis sp. nov. Type No. 8952, F. M. N. H.; length 46 mm.; Mindi, Canal Zone, Panama. Head 3.06 to 3.4; depth 5.25 to 5.86; D. VI-I, 9; A. I, 9; scales 30 to 34. 362 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Body elongate, anteriorly subcylindrical, posteriorly compressed; head as wide as deep, its width at preopercular margin 1.7 to 2 in its length, the upper profile straight or slightly convex; snout rather broad, 3.7 to 4.1 in head; eye moderate, partly superior, 4.15 to 5.86; inter- orbital narrow, 8.75 to 10; mouth large, oblique; the lower jaw strongly projecting; maxillary reaching to or past middle of eye, 2 to 2.5 in head; teeth all small, pointed, in a broad band in each jaw; gill-membranes rather narrowly connected with the isthmus, the opening extending forward to vertical from posterior margin of eye; scales rather large, thin, weakly ctenoid, none on head, chest or predorsal region, 7 or 8 rows between base of second dorsal and base of anal; origin of first dorsal about midway between tip of snout and base of last ray of second dorsal, the spines weak, the longest reaching opposite first or second ray of second dorsal when deflexed; origin of second dorsal slightly in advance of origin of anal, the rays rapidly increasing in length posteriorly, the longest reaching base of caudal in our largest examples, proportionately shorter in the smaller ones; caudal fin with only a few scales at base, the margin rounded; anal fin similar to second dorsal; ventral fins rather long, reaching nearly or quite to vent; pectoral fins reaching opposite origin of anal, 1.12 to 1.38 in head. Color olivacious; back and sides with dark points and blotches; 4 or 5 saddle-like bars on back; a series of elongate blotches on median line of side; caudal spot present. Dorsals and caudal with dark bars; anal fin dusky; other fins unmarked. We have 40 specimens of this species, ranging from 38 to 64 mm. in length. These were all taken in a very muddy brackish creek at Mindi near the Atlantic coast of the Canal Zone. The intestinal canal is short; the air bladder thin, adnate to the back. The ovaries in specimens (captured on Jan. 28, 1911) only 45 mm. in length are distended with well developed eggs, showing that individuals of this size are mature. 54. Microeleotris gen. nov. Type Microeleotris panamensis sp. nov. Body elongate, anteriorly depressed, caudal peduncle compressed; head low and broad; eyes superior; interorbital narrow; mouth large, oblique; lower jaw strongly projecting; gill-openings extending forward to vertical from posterior margin of eyes; no preopercular spine; teeth all small, pointed, in bands on the jaws, none on vomer; scales large, ctenoid, head, chest and part of abdomen naked; dorsal fins 2, well separated; caudal fin rounded; ventral fins separate, I, 5. Carniverous. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 363 KEY TO THE SPECIES. a. Scales in lateral series 33 to 36; second dorsal with I, 8 rays; anal I, 8. panamensis sp. nov., p. 363. aa. Scales in lateral series 3 o to 3 2 ; second dorsal with 1 , 9 rays ; anal 1,9. mindii sp. nov., p. 364. 89. Microeleotris panamensis sp. nov. Type No. 8953, F. M. N. H.; length 50 mm.; Rio Juan Diaz, Panama. Head 3. 25 to 3. 6; depth 4.75 to 5.5; D. VI-I, 8; A. 1, 8; scales 33 to 36. Body anteriorly depressed; caudal peduncle compressed; head de- pressed, notably wider than deep, its width at preopercular margin 1.25 to 1.42 in its length; the upper profile slightly convex; snout tapering, its length 3.4 to 4 in head; eye rather small, superior, 4 to 5.64; inter- orbital narrow, 5.5 to 7.25 in head; mouth rather large, oblique; the lower jaw strongly projecting; maxillary scarcely reaching middle of eye, 2.04 to 2.8 in head; teeth all small, pointed, in bands in the jaws; gill-membranes rather narrowly attached to the isthmus, the openings extending forward to vertical from posterior margin of eye; scales large, ctenoid, none on head, chest and abdomen, 7 or 8 rows between base of dorsal and base of anal; origin of first dorsal about midway between tip of snout and base of last ray of second dorsal, the spines short and weak, reaching second dorsal when deflexed; origin of second dorsal slightly in advance of origin of anal, the rays short; caudal fin not scaly at base, its margin evenly convex; anal fin similar to second dorsal; ventral fins short, failing to reach vent, inserted under base of pectorals; pectoral fins moderate, 1.18 to 1.4 in head. Color grayish brown above, pale below. Body above and on sides spotted and marbled with dark markings; back sometimes with a few dark saddle-like bars; sides often with quadrate blotches; a more or less distinct caudal spot present. Dorsals, caudal, and usually the pectorals spotted and barred with dark markings; anal and ventrals pale or dusky. This species is represented by 38 specimens, ranging from 30 to 58 mm. in length. These were taken in fresh water, not far above the head of tide, in the Rio Chorrera near Chorrera and in the Rio Juan Diaz at Juan Diaz on the Pacific slope. The intestinal canal is short. The stomachs examined contained small molluscs, principally snails. The ovaries in two specimens, each about 45 mm. in length, taken on April 4, 1911, were distended with well developed eggs, showing that fish of this size are mature. A specimen 50 mm. in length from the Rio Juan Diaz has been designated as the type. Habitat: Pacific slope of Central Panama. 364 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. 90. Microeleotrls mindii sp. nov. Type No. 8954, F. M. N. H.; length 55 mm.; Mindi, Canal Zone, Panama. Head 3.2 to 3.5; depth 4.83 to 6.68; D. VI-I, 9; A. I, 9; scales 30 to 32- Body anteriorly depressed; caudal peduncle compressed; head low, wider than deep, the width at preopercular margin 1.45 to 1.75 in its length; snout broad, 3.25 to 4 in head; eye superior, 3.7 to 4.65; inter- orbital very narrow, 8.65 to 12; mouth rather large, oblique; lower jaw strongly projecting; maxillary scarcely reaching opposite middle of eye, 2.17 to 2.6 in head; teeth all small, pointed, in bands in the jaws; gill- membranes narrowly attached to the isthmus, the openings extending forward to nearly under posterior margin of eye; scales large, ctenoid; head, predorsal region, chest and median line of abdomen naked; 7 rows between base of second dorsal and base of anal; origin of first dorsal about midway between tip of snout and base of last ray of second dorsal, the spines weak, reaching second dorsal; origin of second dorsal a little in advance of origin of anal, the rays short; caudal fin without small scales on base, the margin rounded; anal fin similar to second dorsal; ventral fins short, failing to reach vent, inserted under base of pectorals; pectoral fins moderate, reaching past tips of ventrals, 1.13 to 1.5 in head. Color olivaceous; the back with 4 dark saddle-like blotches; median line of sides with elongate dark blotches; a small caudal spot present. Dorsals and caudal with indistinct dark bars or spots; anal fin with more or less dusky, other fins unmarked. We have 51 specimens of this species, ranging from 30 to 56 mm. in length. These were taken in a brackish creek at Mindi near the Atlan- tic coast of the Canal Zone. This species differs from M. panamensis in the somewhat less strongly depressed body, narrower interorbital, fewer scales in the lateral series, one more ray each in the second dorsal and anal, and in the lighter coloration. A specimen 55 mm. in length has been designated as the type. 55. Hemieleotris gen. nov. Type Ekotris latifasciatus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1912, 68. Body elongate, compressed; head compressed, not flat above, mostly covered with scales, the upper surface from eyes forward naked; mouth moderate, oblique; lower jaw projecting; no preopercular spine; teeth small, in bands on the jaws, none on vomer; gill-openings extending DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 365 forward to posterior margin of eye; scales large, ctenoid, present on body and chest; dorsal fins 2, well separated; caudal fin rounded; ven- tral fins separate. Carniverous. 91. Hemieleotris latifasciatus (Meek & Hildebrand). Eleotris latifasciatus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zoot. Ser., X, 1912, 68 (Rio Cardenas, Pacific slope, Panama); Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 131 (Jesus Maria, Costa Rica). Head 3.4 to 4; depfh 3.6 to 4.75; D. VI-I, 9; A. I, 10; scales 35 to 39. Body compressed; head compressed, notably deeper than broad, not flat above, profile straight or slightly concave over eyes; snout tapering, 3.8 to 4.7 in head; eye rather large, 3.5 to 4.15; interorbital 3.9 to 5.2; mouth moderate, oblique; the lower jaw projecting; maxillary reaching to or slightly past anterior margin of eye, 3.25 to 3.9 in head; teeth small, pointed, in bands in the jaws; gill-rakers feebly developed; gill-mem- branes attached to the isthmus, the openings extending forward to under posterior margin of eye; scales large, ctenoid, 10 or n rows be- tween base of second dorsal and base of anal; origin of first dorsal about midway between tip of snout and base of last ray of second dorsal, the spines weak, the anterior ones somewhat produced, reaching opposite the second or third ray of second dorsal; origin of second dorsal slightly in advance of origin of anal, or about midway between middle of eye and base of caudal; caudal fin with a few small scales at base, its margin rounded; anal fin similar to second dorsal; ventral fins long, reaching vent, inserted under base of pectorals; pectoral fins moderate, reaching tips of ventrals, 1.04 to 1.25 in head. Color dark green above, paler below. Sides with a well defined, black band, extending from tip of snout through eye to and on base of caudal. Fins unmarked. This species is represented by n specimens, ranging from 27 to 80 mm. in length. This fish was taken in fresh water streams on the Pacific slope from the Rio Chorrera to the Rio Bayano. The air bladder is thin, adnate to the back; intestine very short; stomach without blind sacs. Habitat: Pacific slope rivers, from Costa Rica to Panama. 56. Genus Awaous Steindachner. Awaous Steindachner, Verh. Mat. Phys. Naturw., 1860, 289 (after Cuvier & Valenciennes, les Awaous (ocularis, etc.)). 366 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Chonophorus Poey, Memories, II, 1861, 274 (type Chonophorus buc- culentus Poey = Gobius taiasica Lichtenstein). Body elongate, anteriorly subcylindrical, posteriorly compressed; head rather low and broad; eyes placed high; mouth large, horizontal; upper jaw more or less projecting; the lips thickened; shoulder girdle with 2 or more dermal flaps, projecting into gill-cavity and covered by opercle; gill-openings rather small, scarcely produced forward; teeth pointed, in narrow bands in the jaws, none on vomer; scales small, mostly ctenoid; head and chest mostly naked; dorsal fins 2, well separated; caudal fin rounded; ventral fins completely united, forming a disc, free from the body. This genus is represented by 2 species in Panama, which are closely related, but differ somewhat in several characters. KEY TO THE SPECIES. a. Scales very small, 69 to 76 in lateral series; about 20 rows between base of anterior rays of second dorsal and anal; mouth moderate, the maxillary failing to reach vertical from anterior margin of eye, about 2.7 in head in specimens 150 mm. in length; fins low, the spinous dorsal failing to reach origin of second dorsal when deflexed; sides with dark blotches, but without black cross-bars. taiasica, p. 366. aa. Scales somewhat larger, 60 to 67 in lateral series, about 16 rows between base of anterior rays of second dorsal and anal; mouth large, the maxillary reaching vertical from anterior margin of eye, about 2.1 in head in specimens 150 mm. in length; fins high, the spinous dorsal usually reaching to or past origin of second dorsal when deflexed; sides with dark blotches and with narrow, black cross-bars. transandeanus, p. 368. 92. Awaous taiasica (Lichtenstein). Gobius taiasica Lichtenstein, Berl. Abhandl., 1822, 273 (Brazil). Gobius banana Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 103 (San Domingo); Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 59. Gobius martinicus Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 105 (Martinique). Chonophorus bucculentus Poey, Memorias, II, 1861, 275 (Cuba). Rhinogobius contractus Poey, Memorias, II, 1861, 424 (Cuba). Rhinogobius bucculentus Poey, Synopsis, 1868, 394. Gobius dolichocephalus Cope, Trans. Amer. Philo. Soc. Phila., 1869, 403 (near Orizaba, Mexico). Euctenogobius latus O'Shaughnessy, Ann. & Mag. Nat. Hist., Ser. 4, XV, 1875, 146 (Bahia, Brazil). DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 367 Chonophorus taiasica (in part) Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 500; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 131 (East slope of Costa Rica). Chonophorus mexicanus Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 501 (Eastern slope of Mexico). Awaous taiasica Jordan, Proc. Cal. Ac. Sci., ad Ser., V, 1895, 494 (Presi- dio) ; (in part) Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2236. Awaous mexicanus Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2237. Chonophorus banana (in part) Regan, Biol. Cent. Amer., Pisces, 1905, ii. Head 3.4 to 3.9; depth 4.75 to 5.55; D. VI-I, 10; A. I, 10; scales 69 to 76. Body anteriorly subcylindrical, posteriorly compressed; head rather large, wider than deep; snout long, 2.04 to 2.6 in head; eye small, 5.25 to 7.5; interorbital 6.25 to 9.7; mouth large, horizontal; upper jaw pro- jecting, the lip thickened; maxillary not quite reaching anterior margin of eye, 2.5 to 3 in head; teeth small, pointed, in a narrow band in each jaw; gill-openings rather small, the membranes broadly attached to isthmus; scales small, ctenoid, except the reduced scales on predorsal region and abdomen; about 20 rows of scales between anterior rays of second dorsal and anal; head and chest mostly naked; origin of first dorsal notably nearer snout than base of last ray of second dorsal, the spines short and weak, rarely reaching second dorsal; origin of second dorsal about midway between posterior margin of eye and base of cau- dal, the rays rather short; caudal fin scaly at base, the margin rounded; anal fin similar to second dorsal; ventral fins not much longer than snout; pectoral fins rather short, 1.3 to 1.73 in head. Color yellowish green; back and sides spotted and mottled with dark brown; a series of dark blotches along side; sides of head usually with a few dark stripes. Dorsals, caudal and sometimes the pectorals with dark spots on the rays forming cross-bars; pectorals with a short black bar at base of upper rays, running downward and backward; anal and ventrals unmarked. Of this species we have 48 specimens, ranging from 50 to 215 mm. in length. These were taken at various places in the Chagres Basin, but always in fresh water, most usually in the lower courses of the streams, but a few of them are from the Upper Chagres. We have compared specimens from Guatemala and Costa Rica with our Panama material and find that the differences between the Pacific and Atlantic slope forms as set forth in the above key also are true for 368 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. these specimens. It is probable that all the Atlantic slope specimens from Mexico to Brazil belong to this species. Habitat: Atlantic slope rivers, from Mexico south to Brazil, and the West Indies. 93. Awaous transandeanus (Giinther). Gobius transandeanus Gunther, Cat. Fish. Brit. Mus., Ill, 1861, 62 (Western Ecuador). Chonophorus taiasica (in part) Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 500. Awaous taiasica (in part) Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2236. Awaous nelsoni Evermann, Proc. Biol. Soc. Wash., XII, 1898, 3 (Sinaloa, Mexico); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2235- Gobius giintheri Regan, Ann. & Mag. Nat. Hist., Ser. 7, XII, 1903, 629 (Western Ecuador). Chonophorus transandeanus Regan, Biol. Cent. Amer., Pisces, 1905, 12; Meek, Field Mus. Nat. Hist. Pub., Zool. Ser., X, 1914, 131 (West slope of Costa Rica). Head 3 to 3.8; depth 5.1 to 5.9; D. VI-I, 10; A. I, 10; scales 60 to 67. Body anteriorly subcylindrical, posteriorly compressed; head large; wider than deep; snout long, 2.1 to 2.5 in head; eye small, 5 to 6.9; inter- orbital 6.5 to 10 ; mouth large, horizontal; upper jaw projecting, the lips much thickened; maxillary reaching vertical from anterior margin of eye, 2 to 3.1 in head; teeth small, pointed, in a narrow band in each jaw; scales rather larger than in A. taiasica, about 16 rows between anterior rays of second dorsal and anal; head and chest mostly naked; origin of first dorsal slightly nearer tip of snout than base of last ray of second dorsal, the spines of moderate length, usually reaching to or more often past origin of second dorsal; origin of second dorsal a little in advance of anal, about midway between anterior margin of eye and base of caudal, the rays rather long; caudal fin scaly at base, its margin rounded; anal fin similar to second dorsal; ventral fins somewhat longer than snout; pectoral fins of moderate length, 1.38 to 1.8 in head. Color yellowish green; back and sides with dark markings; a series of dark blotches along median line of side, at each blotch there is a narrow, black cross-bar; sides of head with dark bars. Dorsals, caudal and usually also the pectorals with dark spots on the rays, forming cross- bars; pectoral with a short black bar at base of upper rays, running back- ward and downward; anal and ventrals unmarked. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 369 This species is represented by over 100 specimens, ranging from 33 to 200 mm. in length. Common in all the streams of the Pacific slope of Panama from the Rio Chame eastward to the Rio Tuyra, ranging from the head of tide to the upper courses of the streams. This species differs slightly from the preceding in several respects. The principal differences are mentioned in the key. We have compared our specimens with specimens from the Pacific slope of Costa Rica and of Colombia and find them all to be identical. It is probable that all the Pacific slope specimens from Mexico to Ecuador belong to this species. Habitat: West slope rivers from Mexico south to Western Ecuador. 57. Genus Sicydium Cuvier & Valenciennes. Sicydium Cuvier & Valenciennes, Hist. Nat. Poiss., XII, 1837, 167 (type Gobius plumieri Bloch). Cotylopus Guichenot, in Maillard, Notes sur Flsle de la Reunion, II, 1864, Addendum 9 (type Cotylopus acutipinnis Guichenot). Sicya Jordan & Evermann, Report U. S. Fish Comm., 1896, 456 (type Sicydium gymnogaster Grant). Body elongate, anteriorly subcylindrical, posteriorly compressed; head low, broad; eyes lateral, placed high; snout very blunt; mouth horizontal; upper jaw in advance of the lower; the lips thick; teeth in upper jaw in a single series, numerous, slender, curved inward, tri- cuspid, bicuspid, or simple; lower jaw with 2 series, the outer series nearly horizontal and partly or completely hidden in the gums, the second series pointed and nearly vertical, none on vomer; gill-opening vertical, not extended forward; body nearly or entirely covered with small ctenoid scales; dorsal fins 2, well separated; caudal fin rounded; ventral fins united, more or less attached to abdomen, forming a sucking disc. But one species of this genus was taken by us. 5. pittieri Regan, recorded from Panama, was not seen. 94. Sicydium salvini Grant. Sicydium salvini Grant, Proc. Zool. Soc. London, 1884, 159, PI. XII, fig. 2 (Panama) ; Regan, Biol. Cent. Amer., Pisces, 1905, 10 (Panama; Western Ecuador). Sicyopterus salvini Jordan & Eigenmann, Proc. U. S. Nat. Mus., IX, 1886, 485. Cotylopus salvini Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1898, 2208. Oreogobius rosenbergii Boulenger, Ann. & Mag. Nat. Hist., Ser. 7, IV, 1899, 126 (Western Ecuador). 370 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. X. Head 4.17 to 4.85; depth 4.85 to 5.75; D. VI-I, 10; A. I, 10; scales 70 to 86. Body elongate, anteriorly subcylindrical, posteriorly compressed; head short, quadrate, as wide as deep; snout very short and blunt, anterior profile nearly vertical, its length 2.2 to 2.96 in head; eye small, lateral, placed high, 4.7 to 5.75; interorbital 3 to 4.3; mouth large, hori- zontal, inferior; the upper jaw notably in advance of the lower, the lip thickened; maxillary reaching to or past posterior margin of eye, 1.7 to 2.2 in head; teeth in upper jaw in a single series, very slender, recurved, somewhat compressed and grooved at apices, tricuspid in young, with nearly smooth cutting edge in adult; lower jaw with 2 series of teeth, the outer series nearly horizontal, directed forward, more or less exposed in young, but completely hidden in the gums in adult; second series composed of comparatively few, rather strong, vertical or slightly re- curved, pointed teeth; gill-openings vertical, not extending forward; scales small mostly ctenoid, extending forward nearly to interorbital region; abdomen completely covered with scales; those on predorsal region and abdomen very small and partly embedded; origin of first dorsal about midway between posterior margin of eye and origin of second dorsal, the spines produced in adult males, sometimes reaching past middle of base of second dorsal; origin of second dorsal midway between posterior margin of eye and base of caudal or slightly nearer the latter, notably higher in adult males than in females; caudal fin scaly at base, the margin rounded; anal fin similar to second dorsal, but scarcely as high; ventral fins forming almost a perfect circular disc; pectoral fins broad at base, rounded, 1.05 to 1.4 in head. Color dark green. Young with a dark lateral band, which later breaks up into more or less confluent spots; sides also with dark cross- bars, which are very indistinct in our largest specimens; back in young with dark reticulations; scales usually with roundish spots which are largest and most distinct on caudal peduncle. Dorsal fins spotted or not; anal fin with a dark stripe near its margin. We have 8 specimens of this species, ranging from 55 to 100 mm. in length. One of these was taken at Paraiso, on the Pacific slope, in a small tributary of the Rio Grande, and the others are from various places in the Chagres Basin. We are unable to separate the Pacific slope specimen from those of the Rio Chagres. Our specimens were all taken in upland streams where the species inhabits the rocky rapids. By means of its ventral sucking disc, it is able to cling closely to the rocks and is extremely difficult to capture. It is therefore quite certainly not as rare as the small number captures would indicate. Habitat: Both slopes of Panama and Western Ecuador. GLOSSARY OF TECHNICAL TERMS. Abdomen. The belly; the cavity containing the digestive and repro- ductive organs. Adipose fin. A peculiar, fleshy fin without rays but occasionally with a spine, occurring on the back behind the dorsal fin of most cat fishes, characins, etc. Air-bladder. A sac filled with air, lying beneath the backbone and in or behind the abdominal cavity; also known as swim-bladder. Anal. Pertaining to the anus or vent. Anal fin. The fin on the median line behind the vent. Antrorse. Turned forward. Anus. The external opening of the intestine; the vent. Articulate. Jointed; said of soft fin rays. Azygous. Occurring singly; not paired. Barbels. An elongate fleshy projection, usually about the head; also called whiskers, present in most cat fishes. Bicuspid. Having two points. Branchiae. The gills. Branchiostegals. Slender bones forming the support for the branchi- ostegal membranes lying under the head and below the opercular bones. Canines. Long conical teeth. Carinate. Keeled; having a single ridge along median line. Caudal. Pertaining to the tail. Caudal fin. The fin on the tail. Caudal peduncle. The region between the anal and caudal fins. Cirri. Fringes. Ccecum. An appendage of the form of a blind sac connected with the posterior end of the stomach, or pylorus. Compressed. Flattened from side to side. Ctenoid. Rough-edged; said of scales when the posterior margin is spinous or pectinate. Cycloid. Smooth-edged; said of scales when the posterior margin is not rough; scales showing concentric lines or striations. Deciduous. Falling away or out. Decurved. Curved downward. Dentary. The principal or anterior bone of the lower jaw or mandible. Depressed. Flattened vertically. 372 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. X. Distal. Remote from the point of attachment. Dorsal. Pertaining to the back. Dorsal fin. The fin on the median line of back. Emarginate. Slightly notched at the end. Falcate. Scythe-shaped; long, narrow and curved. Fauna. The animals inhabiting any one region, taken collectively. Filament. Any slender or thread-like structure. Filiform. Thread form. Fontanel. An opening between the bones of the skull. Foramen. A hole or opening. Frontal bone. Anterior bone on top of head, usually paired. Fusiform. Spindle shaped; tapering toward both ends. Gape. Opening of the mouth. Gill-arches. The bony arches to which the gills are attached. Gill-openings. Openings reaching to or from the gills. Gill-rakers. A series of bony projections placed along the inner edge of the gill arch. Gills. Organs for breathing the air contained in water. Haemal spine. The lowermost projection of a caudal vertebra. Incisors. Cutting teeth, usually in front of jaws. Interorbital. Space between the orbits or eyes. Isthmus. The region between the lower part of the gill-openings. Keeled. Having a ridge along the median line. Lamellae. A thin plate, layer or process. Larva. The immature form. Lateral. Referring to the side. Lateral line. A series of mucus pores along the side of the fish and containing sense organs. Mandible. The lower jaw. Marbled. Variegated; clouded. Maxillaries. The outermost bones of the upper jaw, joined to the pre- maxillaries in front, and usually extending farther back than^the latter. Nape. The back of the neck. Nares. Nostrils. Nasal. Pertaining to the nostrils. Nuchal. Referring to the nape. Obsolete. Poorly developed; scarcely evident. Obtuse. Blunt. Occipital. Relating to the occiput. Occiput. The back of the head. Ocellated. Having an ocellus or ocelli. DEC. 28, 1916. FISHES OF PANAMA — MEEK AND HILDEBRAND. 373 Ocellus. An eye-like spot; a dark spot with a lighter border. Opercle. The thin flat bone on sides of head covering the gills; also called gill-covers. Orbit. Eye socket. Osseous. Bony. Oviparous. Reproducing by means of eggs laid and hatched outside of the body. Ovum (plural ovi). Egg. Palate. The roof of the mouth. Palatines. Bones of the roof of the mouth, one on each side of the vomer, often provided with teeth. Papilla. A small fleshy projection. Papillose. Covered with papillae. Parietal. Bone of the side of the head. Pectinate. Having teeth like a comb. Pectoral. Pertaining to the breast. Pectoral fins. The anterior or uppermost paired fins, corresponding to the anterior limbs of the higher vertebrates. Peritoneum. The membrane lining the abdominal cavity. Pharyngeal bones. Bones behind the gills and at the beginning of the oesophagus, usually provided with teeth. Plicate. Folded; showing folds or wrinkles. Plumbeous. Lead colored; dull bluish gray. Postorbital. Behind the eye. Premaxillaries. The bones, one on each side, forming the front of the upper jaw, usually bearing most of the upper teeth. Preopercle. A thin bone lying just in front of the opercle. Preorbital. The bone lying just in front of the eyes. Protractile. Capable of being drawn forward. Pseudobranchiee. Small gills developed on the inner side of the opercle. Punctate. Dotted with fine points. Ray. One of the bony or cartilaginous supports of a fin. Rays are either spiny or soft, the latter are either simple or branched. Recurved. Turned backward or toward the point of origin. Reticulate. Marked with a net work of lines. Retrorse. Turned backward. Rudimentary. Undeveloped. Rugose. Rough, wrinkled. Scute. An external horny or bony plate. Serrate. Notched like the edge of a saw. Setiform. Having the form of a bristle. Snout. That portion of the head which projects beyond the eyes. 374 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. X. Spinous. Stiff or composed of spines. Striate. Striped or streaked. Suborbital. The bone immediately below the eye. Supraoccipital. The bone at posterior part of skull. Suture. The line of union of two bones, as in the skull. Symphasis. The tip of chin; point of juncture of the two bones of lower jaw. Synonym. A different word having the same meaning; a technical name given to a fish already described is said to be a synonym. Synonymy. A list of technical names applied to a certain genus or species. Tail. In ichthyology the part posterior to the anal fin. Temporal. Referring to the region of the temples. Terete. Cylindrical or tapering. Thoracic. Pertaining to the thorax; said of the ventral fins when attached beneath the pectorals. Trenchent. Compressed to a sharp edge. Truncate. With a square or straight margin. Tubercle. A small projection, like a pimple. Type. The particular specimen upon which the original description of the species was based or the species upon which was based the genus to which it belongs. Type locality. The particular place or locality at which the type was collected. Vent. The posterior opening of the alimentary canal. Ventral. Relating to the abdomen. Ventral fins. The paired fins behind, in front of or below the pectoral fins, corresponding to the hind limbs in the higher vertebrates. Ventral plates. The plates lying on the belly. Vertical fins. The fins on the median line of the body; the dorsal, caudal and anal fins. Villiform. Slender, minute teeth crowded into compact patches or bands. Viviparous. Bringing forth living young. Vomer. A bone in the center of the roof of the mouth, just behind the premaxillaries, often bearing teeth. UNIVERSITY OF ILLINOIS-URBANA