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no Reprinted from the Revorts OF PRINCETON UNIVERSITY EXPEDITIONS TO PATAGONIA, 1896-1899, Vol. ILI. i 
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PART -V; 


NON-MARINE MOLLUSCA OF PATAGONIA. 
HENRY A; PIESBRY, 
AcADEMY OF NATURAL SCIENCES, PHILADELPHIA. 


This report deals with the non-marine mollusks of Tierra del Fuego 
and Patagonia as far north as the thirty-ninth parallel, where the Rio 
Negro Valley forms a transition region, the Patagonian fauna giving place 
to the La Platan. 

The scope of the work has been extended to include some account of 
all the South American forms of certain little-known families, such as the 
Ammnicolide and Spheriude, and all of the Chzlinide occurring east of the 
Andes. Finally, the relationships of the South American molluscan fauna 
with the faunas of other continents are considered. 

The collections made by Mr. J. B. Hatcher and placed in my hands by 
Professor William B. Scott form the basis of this report. The material 
from the region along the Rio Chico de la Santa Cruz and in the base of 
the Andes above its head is ample. Elsewhere but few mollusks were 
collected, and I have used material which I owe to the generosity of Dr. 
H. von thering, Director of the Museu Paulista, Dr. W. H. Rush, U.S.N., 
and others. 

ZONAL DISTRIBUTION OF PATAGONIAN MOLLUSCA. 


An inspection of the data existing on Patagonian mollusks shows that 
several faunulas largely distinct in species occupy zones extending from 
the Atlantic to the Andes and succeeding one another from north to south. 
So far as aquatic animals are concerned, these zones are determined by 
the drainage systems, which are separated by poorly watered plains, and 
flow independently into the Atlantic. The aquatic mollusks known from 
these several zones are enumerated below. 

Chitina, Lymnea and Prstdium are the only genera of fresh-water mol- 
lusks which extend throughout Patagonia, the first two also in Tierra del 


513 


514 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Fuego. The Unxzonide and Mutelde, groups copiously represented in the 
La Plata, have their southern limit in the Rio Negro, each represented by 
one species ; Planorbis has two, Anucylus one species, the rest of the fauna 
being Patagonian. The Rio Negro fauna, including the region of Bahia 
Blanca, is transitional also in land mollusks, the genera Balimulus, Odon- 
tostomus and Strophocheilus reaching their southern limit in the Sierra 
Ventana, near Bahia Blanca. In the humid region west of the Cor- 
dillera the faunal zones are deflected southward, the transition zone as 
marked by the southern limit of Unzonzd@ being in the neighborhood of 
Chiloe Island. That the transverse faunal zones of Patagonia run north- 
ward in the Andean region is shown by the occurrence on the upper Rio 
Chico of several Magellanic forms. 


I. La PLATAN ZONE.! 


Includes the Plata and its tributaries in Argentina, Uruguay, Paraguay, 
Brazil, and rivers flowing into the Atlantic in the Brazilian states of Sao 
Paulo and Rio Grande do Sul. Except in Chz/inid@, only the genera of 
this fauna are mentioned below, the species being very numerous. 
Chilinidee: Chelina fluminea, C. f. microdon, C. globosa, C. rushit, C. parva, 

C. portillensts, C. tehuelcha mendozana. 
Physidz: Physa. 
Lymneide: Lymnea, Planorbis. 
Ancylide: Aucylus. 
Amnicolide: Lettorzdina, Potamopyrgus, Potamolthus. 
Ampullariide: Ampullaria, Asolene. 
Cyrenidze: Corbscula. 
Spheeriidee: Musculium, Pisedium. 
Unionide: Dzplodon, Castalia, Castalina. 
Mutelidz: Axodontites, Letla, etc. 


IJ. PATAGONIAN ZONE. 


A. Rio Negro Fauna.’ 


(All of the known aquatic mollusks of this fauna and those following 
are enumerated.) 


‘Probably the La Platan fauna is a subdivision of the Amazonian, chiefly characterized by the 
great development of Chelintde and Amnicolde. 
* Including also the Rio Colorado, and known solely by the works of d’Orbigny and Doering. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 515 


Chilinidze: Chelina tehuelcha, C. puelcha, C. parchappit. 
Lymneide: Lymnea viator, Planorbis peregrinus, P. anatinus. 
Ancylide: Aucylus concentricus bonariensts. 

Amnicolide: Lifforidina parchappi, L. australis. 

Spheeriidze: Not reported, but doubtless present. 

Unionidee: Diplodon patagonicus. 

Mutelidz : Anodontites puelchana. 


B. R20 Chubut Fauna. 
Unknown. 


C. Rio Santa Cruz Fauna. 


Chilinidee: Chzlina strebelt, C. smithi, C. fulgurata, C. f. oligoptyx, C. f. 
hivida, C. f. andicola, C. f. hatcheri, C. campylaxts, C. monticola pilula, 
C. lebrunt, C. perriert. 

Lymneide: Lymuea viator, L. diaphana, L. d. inelegans, L. patagonica 
viochicoensis, L. andeana. 

Amnicolidze: Lztloridina hatchert, L. simplex, L. sublineata. 

Spheriide: Muscuhium patagonicum, Pisidium magellanicum, P. pata- 
gonicum, P. observationts. 


D. Magellanic, Fuegian and Falkland Faunas. 


Chilinidze: Chzlina patagonica, C. amena, C. fuegiensis, C. monticola, C. 
Jusca, C. nervosa, C. falklandica. 

Lymneide : Lymnea diaphana, L. patagonica, L. pictonica, L. brunneo- 
flavida. 

Spheriidz: Prsedium magellanicum. 

These several faunas may be roughly compared with the life-zones of 
North America. The La Platan zone is equivalent to the Austral, the Rio 
Negro fauna to the Transition, and the remainder of the Patagonian zone 
to the Boreal zone of the northern continent. 

The distinctness of the Patagonian faunas A, C, D may be attributed 
to three main factors: (1) Climate, which imposes limits on the north 
or south distribution of species. (2) Absence of streams flowing north or 
south, and the consequent isolation of the river systems, favoring the evo- 


‘Known only from the collections of Mr. J. B. Hatcher. 
*From the researches of Captain King, Dr. Coppinger, the U. S. Exploring Expedition, the 
French Expedition to Cape Horn, Dr. Michaelson and others. 


516 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


lution of distinct species. (3) Ignorance of the Patagonian faunas be- 
tween the Rio Negro and the Rio Santa Cruz system, and along the base 
of the Andes, where Transition forms and intermingling of the species 
may occur. 


GASTROPODA. 


Family EVDODONTTD. 


Two genera of this family are known from Patagonia: S/ephanoda and 
Radiodiscus. The relationships of these forms to genera of other regions 
are unknown, since we have as yet no knowledge of their soft anatomy. 
E:indodontide were present in the North American Carboniferous, repre- 
sented by forms resembling the modern Goxyodiscus and Charopa in shell 
characters, and like their descendants, living in and upon decaying stumps. 
The family is now found all over the world, even on the most remote 
islands. 

RADIODISCUS Pilsbry. 
Radtodiscus Pils., Proc. A. N. S. Phila., 1906, p. 154, for R. mlecostatus. 

Minute, discoidal, openly umbilicate Patuloid snails, with the embryonic 
1% whorls minutely engraved spirally, the rest of the shell densely radi- 
ally costulate. Aperture rotund-lunate, but slightly oblique, and as high 
as wide. Type R. mllecostatus Pils. & Ferr. 

In the Exdodontid@, where small differences in the shell characterize 
extensive series of species, it seems desirable to recognize as of generic 
rank such readily definable groups as Radod?scus. 

The distribution of this genus is very wide, extending from Tierra del 
Fuego to the mountain ranges of the southern boundary of Arizona, where 
it meets the Holarctic Gonyod?scus and the Nearctic Helicod?scus, both at 
their southern limits. At present, the known distribution of Radvzodiscus 
is markedly discontinuous, one area extending from southern Arizona to 
central Mexico, the other from southern Brazil to Cape Horn; yet it must 
be remembered that the Andes and northern South America are un- 
searched for minute shells. We know very few so small as these (2 to 
3 mm. diam.); and some of the species imperfectly described may turn 
out to belong to Radiodiscus. It is likely that the group is an Austral 
one, which has invaded Mexico from the south. 

Some Tasmanian snails have a great resemblance to Radodiscus, in 


PILSBRY : NON-MARINE MOLLUSCA OF PATAGONIA. 517 


size, form and sculpture —a resemblance possibly due to convergence, but 
perhaps indicating affinity. I have not been able to actually compare 
specimens. On account of their spirally sculptured embryonic shells 
Hedley has referred them to the subgenus 4//od?scus of the genus -lam- 
mulina.* 

RADIODISCUS COPPINGERI (E. A. Smith). 
Helix (Patula) coppingert Smith, P. Z. S., 1881, p. 36, pl. 4, f. 14, 14a. 
Patula coppingert Smith, Strebel, Zool. Jahrb., XXV, 1907, p. 159. 

The shell is described as 1 X 1% mm., composed of 3% whorls, the 
‘umbilicus moderately small, equalling about one-sixth of the basal 
diameter.” 

It was described from Tom Bay (Dr. Coppinger), found on a rotten 
tree. This is near Madre de Dios Island, on the west coast. Strebel 
reports specimens which he identified as copfzngerd from the west coast 
of Tierra del Fuego, Ushuaia, and NavarinIsland. While this form must 
stand near R. patagonicus, it appears distinct by the much smaller um- 
bilicus, if we may trust the published figures. Ihave not seen specimens. 
The apical sculpture has not been described. 


RADIODISCUS MAGELLANICUS (E. A. Smith). 
Helix (Patula) magellanica E. A. Smith, P. Z. S., 1881, p. 36, pl. 4, figs. 
U5; THe: 
This species, described from the same place as the preceding, will prob- 
ably prove to be a Radtodiscus, when the embryonic whorls are examined. 


RADIODISCUS PATAGONICUS (Suter). 
(Plate XLII, Figs. 1, 1a, 14.) 
Pyramidula patagonica Suter, Revista do Museu Paulista, IV, 1900, p. 
SoA pl: - 3h 6, 6b: 
Stephanoda patagonica Suter, Pilsbry, Proc. A. N. S. Phila., 1900, p. 387, 
pe i; £O=51- 

The shell is openly umbilicate (the umbilicus about one-fourth the total 
diameter), of a uniform pale brown tint, discoidal, the spire convex but 
low, suture deeply impressed. Whorls about 3%, convex, slowly increas- 
ing, the embryonic 1% densely striate spirally, the rest radially costellate, 


‘Of. Flammuliua (Allodiscus) roblini Petterd, as figured by Hedley in Records of the Aus- 
tralian Museum, VII, 1909, p. 300. 


518 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


the riblets about as wide as their intervals, about 25 in 1 mm. on the last 
half of the last whorl. Under the microscope some very minute striations 
may be seen upon the ribs, and in places an extremely minute and very 
faint spiral striation. The rotund-lunate aperture is slightly oblique. 


Alt. 0.9, diam. 1.7 mm. (50 miles above Sierra Oveja). 
‘12° “ 1:8 mm. (Santa Cruz) 


Santa Cruz (v. Ihering, type locality). Near Mt. of Observation. On 
the Rio Chico 50 miles above Sierra Oveja, on a dry stone near the water. 
Spring near base of the Andes, 65 miles north of the Rio Chico, elevation 
2400 ft. Banks ofa small stream 10 miles from Ushe Lake (J. B. Hatcher). 

The above description and the figures are from a shell collected alive 
50 miles above the Sierra Oveja. The original description, in Portuguese, 
was based upon fossil specimens, which had lost the color and part of the 
finer sculpture. The original lot of Jatagonzcus was from Santa Cruz, on 
the coast, in a modern deposit. Part of the original lot is before me. 
They are a little larger than the living shell described, with the whorls 
slightly deeper ; yet in the series examined from all of the localities yet 
known, the very slight differences seem to intergrade. 


STEPHANODA Albers. 


This group comprises Patuloid species in which the embryonic whorl is 
typically smooth, but in some forms now referred here it is marked with 
radial striae, but no spirals. It differs from A7phidoxa (with which I 
formerly united it) by the more numerous, less rapidly widening whorls. 
Without a knowledge of the soft parts, the relationships of these South 
American snails to the Austral Chavopa and Flammu/ina, and to the northern 
Patuliform genera, cannot be defined. The following species from southern 
Patagonia belong here: 

S. dyvata (Gld.), summit of highest mountain near Orange Harbor, etc. 
(Helix lyrata Gld.). 

S. leptotera (Mab. et Rochebr.), Orange Bay (Patula leptotera M. & R.). 

S. vigophila (Mab. et Rochebr.), Orange Bay (Patula r., M. & R.). 

S. michaelsent (Strebel), Magellan Strait to Navarin Island (Patula m., 
Strebel, 1907) 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 519 


Family ZON/IT/IDA. 


The small land snails originally described as Hefzx saxatilis Gld. and 
FH. ordinaria Smith have all the external characters of the //ya/znza group 
of Zonttide. H. saxatilis has pedal grooves and a mucous pore at the 
tail. Mabille and Rochebrune have proposed for it the generic term 
Payenia. What status this group will ultimately be given depends wholly 
upon the internal anatomy, of which we know nothing. It may possibly 
belong to the Axdodontide. 

PAYENIA SAXATILIS (Gld.), U. S. Expl. Exped., Mollusca, p. 42, pl. 3, f. 
33. Orange Harbor, under dry stones. 

PAYENIA ORDINARIA (E. A. Smith), P. Z. S., 1881, p. 36, pl. 4, f. 16, 162. 
Tom Bay, on the west coast, attached to the frond of a fern. 


Family LIMACIDA2. 


Except as introduced animals, Lzmaczd@ are unknown in South America. 
A species of Limax (probably the European Agriolimax levis or A. 
agrestis) has been reported from the Falkland Islands and from Ushuaia, 
Tierra del Fuego (Strebel, Wissenschaftliche Ergebnisse der schwedischen 
Siid Polar-Expedition, die Gastropoden, p. 7, 1908). 

Agrioimax levis under the name Agriolimax argentinus Strobel has 
attained a rather wide distribution in temperate South America. Doering 
reports it from the Rio Colorado, Rio Negro, and Sierra de Cordoba. 


Family SUCCINE/DA. 
SUCCINEA Drap. 
SUCCINEA PATAGONICA E. A. Smith. 


5. paltagonica Smith, P. Z..S., 1881, p. 37, pl. 4, f. 17, 17@; Proc. Malae. 
Soc. London, VI, 1905, p. 338. 

S. lebrunt Mabille et Rochebrune, Miss. Sci. Cap Horn, Moll., p. 14, pl. 6, 
f. 4a, 40. 

The shell is rather ventricose, greenish-yellow, with the first whorl light 
scarlet. Length 12.5 mm. Cockle Cove, shores of Trinidad Channel and 
Puerto Bueno (Dr. Coppinger); Rio McClelland (Capt. Crawshay). 

S. lebvunt seems to differ only in the smaller size of the type specimens, 
length 8-9 mm. —a trivial distinction. It was taken at Punta Arenas 
and Orange Bay. 


520 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Two specimens, the largest 10 mm. long, were taken by Mr. Hatcher 
at Punta Arenas. 

SUCCINEA MAGELLANICA Gould. 

S. magellaniea Gld., U.S. Expl: Exped:; Moll ps 24, pla2)& 22:-sstrebel: 
Zool. Jahrb., XXV, 1907, p. 161, Taf. 8, f. 99; ? Doering, Informe 
Oficial Exped. Rio Negro, 1881, p. 62. 

The shell is ventricose, similar to the preceding, except that the apex is 
notred. Type locality Orange Bay, but reported from numerous localities 
between Punta Arenas and Navarin Island by Strebel (Z c.). It has been 
recorded also from the region of Sierra Ventana, above Bahia Blanca, by 
Dr. Adolfo Doering, but there is a possibility that some similar form has 
been mistaken for S. magellantca. 


SUCCINEA ORDINARIA E. A. Smith. 


S. ordinarvta Smith, Proc. Malac. Soc. London, VI, 1905, p. 338, fig. iv. 
A species with 3 to 3% very convex whorls, length 10.25 mm., diam. 6, 
length of aperture 6 mm. It is ‘apparently very like S. ebrunz Mabille, 
but without the sanguineous apex and rather more coarsely sculptured.” 
I have not seen this species, which is probably closely related to S. magel- 
fanica. Admiralty Sound, Tierra del Fuego (Captain Crawshay). , 


SUCCINEA MERIDIONALIS d’Orbigny. 


Succinea meridionalis d’Orbigny, Voyage dans |’Amér. Meérid., pp. 711; 

Doering, Informe Oficial Exped. Rio Negro, 1881, p. 62 (var. cornea). 

Sierra de la Ventana (d’Orbigny). Swamps in the pampa north of the 
Rio Negro (Doering, for var. cornea Doert.). 


SUCCINEA BURMEISTERI Doering. 
(Plate XLII, Figs. 2-6.) 


Succinea burmerstert Doering, Malakozoologische Blatter fiir 1873, X XI, 
p- 59, Taf. 2, f. 15-19 (Rosario am Parana). 

‘““Gehause eiférmig, zugespitzt, etwas bauchig, durchscheinend, gelb- 
lich-hornfarbig, stark und oft unregelmassig runzelig gestreift, wenig 
glanzend. 3% ziemlich stark convexe und rasch an Weite zunehmende 
Umgdange; der letzte etwas bauchig. Gewinde zugespitzt. Miindung 
gerundet-eifo6rmig, der aussere Rand des ziemlich breiten, obwohl etwas 
undeutlichen Spindel-Umschlages mit dem Mundsaum zusammenhangend. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 521 


“Longit.12 mm. Lat.7.3mm. Apertura8 mm. longa, 5% mm. lata.” 

Dr. Doering’s description and figures apply fairly well to a Succznea of 
the S. avara group, which is abundant and widely distributed in the ter- 
ritory of Santa Cruz, collected at the following stations : 

Near Mt. of Observation (near the coast, south of Santa Cruz River). 

Near Pescadores, south side Santa Cruz River, 15 miles above mouth. 

Spring on Rio Chico, above mouth of Rio Chalia. 

Spring on Rio Chico, north side, near Sierra Ventana. 

Spring on Rio Chico, 7 miles above Sierra Ventana. 

Spring near Sierra Oveja. 

Springs on Rio Chico, 15, 40 and 50 miles above Sierra Oveja, and 25 
and 15 miles below confluence of Rio Belgrano. 

Stream near mouth of the Rio Belgrano. 

Base of Andes, 40 miles north of Rio Chico, 2000 feet elevation. 

Base of Andes, 50 miles north of Rio Chico, 1750 feet elevation. 

Base of Andes, 65 miles north of Rio Chico, 2400 feet elevation. 

Pool near Arroyo Eke, near head of Spring Creek, elevation 1750 
feet. 

Specimens from a spring 7 miles above the Sierra Ventana, ‘on horse 
dung near the water,” are figured, Pl. XLII, figs. 4, 5. 6. The color varies 
from honey-yellow to whitish-yellow, always with the first whorl of a 
deeper yellow shade. The suture is very deep and the whorls extremely 
convex. The specimens figured measure: 


Length 11, diam. 6 mm., length of aperture 6.5 mm.; whorls 3%. 


“c lI ‘c 6.9 “ “c “<‘ 725 “cc “ 3. 
‘6 12:3 ‘6 6.9 “c “ic ‘6 7 “c “cc 334. 


It will be noted that, as compared with Doering’s description, these shells 
have the aperture shorter. 

At all other stations the shells are smaller. Two figured from the Rio 
Chico 50 miles above Sierra Oveja (Pl. XLII, figs. 2, 3) representative of 
this small form measure: 

Length 7.9, diam. 4.9 mm., length of aperture 5 mm.; whorls 3%. 

es teak o> aus Rh, ce f Se. ae cel gears 

In a series of fossil individuals from the banks of a stream 10 miles from 
Ushe Lake (collected January 14, 1898), there is remarkable variation in 
contour, though most of the shells are much lengthened. 


522 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Length 11, diam. 6.1, length of aperture 6.3 mm.; whorls 3%. 


“6 9.8 6c 5.5 “6 66 5 a “é 35%. 
‘“ 8.8 “c 6 (6 “< 533 “c “ 3%. 


Family LYMNALIDA. 
LYMNAZA Lamarck. 


Lymmnea is more widely distributed than any other genus of freshwater 
mollusks, extending from the shores of the Arctic Ocean to Tasmania and 
Cape Horn, and in the Pacific reaching the Hawaiian group. The genus 
in its present limits is a synthetic group, which no doubt will ultimately 
be divided into several genera. 

There are very few species in tropical South America, where the genus 
seems to be of rare occurrence; but in Patagonia the species are more 
numerous, individuals are abundant and generally distributed. South 
American Lymneas fall into three subgenera or sections of the genus. 
Section I is clearly an intrusive element from North America. Sec- 
tion II may possibly be of North American origin, but its relationships 
are unknown, as no specimens with the soft parts have been received. 
Section III is peculiar to Patagonia, and not closely related to any nor- 
thern forms. 

I. Section GaLtBa Schrank. The marginal teeth of the radula differ 
from the laterals by being more oblique, but are essentially “zcuspzd. The 
shell is small, compactly coiled, of very convex whorls, usually umbilicate, 
the columellar lip broadly revolute, not folded. The type is ZL. trancatula 
of Europe. South America species, ZL. veator, L. cousine. 

II. Section ? Dentition unknown. The shell is lengthened, 
fragile, Swccznea-shaped, of few whorls, the last large and elliptical. Z. 
peregrina, L. andeana. 

III. Section PECTINIDENS n. sect. The marginal teeth are broad and 
short, the cusps split into a comb-like series of many narrow denticles. 
Type Lymnea diaphana King. There are two groups of species. 

Group of L. dzaphana. Moderately large, elongated forms, with very 
convex whorls and a narrow umbilical chink. 

Group of L. fatagonica. Small forms, with very short spire (peculiarly 
liable to truncation) and few whorls, the last relatively very large and 
short, rimate or imperforate. L. patagonica, L. p. riochicoensis, L. pic- 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 523 


fonica. Itis possible that the presence of acid in the water, causing erosion 
of the shell, may also account for the stunted stature of these forms. 


DENTITION OF SOUTH AMERICAN LYMNA&AS. 


Dentition of L. viator A Orb.—The radula examined was from one of 
the specimens taken on the Rio Chico near the Sierra Oveja. The central 
tooth is narrow and unicuspid as usual. There are three or four lateral 
teeth, having two long cusps. In the following transition teeth the inner 
cusp (entocone + mesocone) is long and bifid, ectocone simple. The 


Bic. Y- 


Teeth of Lymnea viator d Orb. Rio Chico, Patagonia. 


marginal teeth are very oblique, with three cusps, entocone, mesocone and 
ectocone. In some of the outer marginal teeth there may be one or two 
minute accessory cusps. 

The radula of L. vzafor agrees well with that of the European Z. fram- 
catula as figured by Lehmann. It differs from typical Lywuea by retain- 
ing the primitive tricuspid type of teeth in the marginal series, with few 
small accessory cusps or none. Lymnzas with this type of teeth have a 
continuous distribution from Patagonia to Alaska and in the Palzearctic 
region. 

Dentition of Lymnaea diaphana King. —These are about 30, 7, 1, 7, 
30 teeth. The central tooth is wider than usual in Lymuca, unicuspid. 
The lateral teeth are bicuspid, the broad inner cusp becoming bifid on 
the transition teeth. The inner marginals have the mesocone and ento- 


Hic; 2) 


SS Baw. 


Teeth of Lymnea diaphana King.~ Rio Chico, Patagonia. 


cone split into four to six small cusps, the ectocone remaining simple. 
Further out the marginals become transversely lengthened, their cusps lie 


524 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


parallel to the long axis of the tooth, and are split into a comb-like series 
of denticles. 

The marginal teeth of Z. waphana differ from those of typical Lymucea 
by their prostrate position, the cusp of one tooth overlying the basal plate 
of the succeeding one in the same transverse row, and also by the comb- 
like cusps. In typical Lymne@a (L. stagnalis, fig. 3) the cusp stands 
obliquely erect, its cutting edge transverse to the long axis of the tooth. 


Fig. 4. 
Marginal teeth of Lymnca stagnalis L. Two outer lateral and two inner marginal 
(after Dybowsk1). teeth of Lymnea patagonica riochicoensis Pils. 


Lymnea patagonica riochicoensts (fig. 4, two outer lateral and two inner 
marginal teeth) has a radula closely resembling that of ZL. daphana. 
There are ten lateral teeth. 

No Lymuea of the northern hemisphere, of which the teeth are known, 
has marginals like those of L. dzaphana, but I have shown that some- 
what similar teeth exist in a Hawaiian species.! 


' Figures of Lymnzid teeth may be found in the following works, among others : 

Lehmann: Die lebenden Schnecken und Muscheln der Umgegend Stettins und in Pommern, 
NO735) lal 15.) LO: 

J. Hazay: Malak. Blatter, n. F., VII, Taf. 1 (Lymunea auricularia, ovata, peregra). 

W. Dybowski: Studien iiber die Zahnplatten der Gattung Limnzea Lam., in Bull. Soc. Imp. 
Naturalistes de Moscou, LX, 1884, pt. 2, pp. 256-262, pl. 5 (L. stagnalis var. vulgaris). The 
best figures of ZLymne@a teeth published. Also, Malak. Blatter, n. F., VIII, p. 124, Taf. 7 
(Amphipeplea glutinosa). 

R. P. Whitfield: Description of Lymnaea (Bulimnea) megasoma Say, in Bull. Amer. Mus. Nat. 
Hist., 1, 1882) p: 20; pls. 

Fischer et Crosse: Mission Scientifique au Mexique, Mollusques, II, pl. 36 (LZ. auricularia). 

F. C. Baker: A revision of the Limnzas of northern Illinois, in Trans. St. Louis Acad. Sci., 
XI, 1901, pp. 1-24. 

H. A. Pilsbry: Proc. A. N. S. Phila., 1903, p. 790 (L. hawaziensis). 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 525 


Section GALBA Schrank. 


LYMN4A VIATOR d’Orbigny. 
(Plate XLVI, Fig. 8). 


Limneus viator AOrb., Magazin de Zoologie, 1835, p. 24; Voy. dans 
l’Amér. Mérid., Moll., p. 340, pl. 43, figs. 1-3. 

A species of the group of ZL. truncatula. The shell is small and 
smoothish, composed of five very convex whorls, joined by a very deep 
suture ; the aperture is oval or nearly round, more than half the length of 
the shell. The axis is very distinctly umbilicate. Length 8, diam. 4 mm. 

d’Orbigny records this species from the banks of the Rio Negro, 41° S. 
lat., 7 or 8 leagues above the mouth, very abundant. This may be con- 
sidered the type locality. Afterwards he collected it also at Santiago, 
Chili, and at Callao and Lima, Peru, in irrigation ditches. The speci- 
mens from Peru, he notes, are constantly more elongate than those of 
Patagonia and Chili, with the whorls more deeply separated. Dr. W. H. 
Rush collected many specimens in a creek in the Prado, at Montevideo, 
Uruguay. These specimens, with others from Lima before me, do not 
seem separable from the Antillean ZL. cubenszs Pfr. (1840) by any character 
in the shells. 

Specimens from a pool on the bank of the Rio Chico, a mile west of 
the Sierra Oveja (Pl. XLVI, fig. 8) are larger than those from Uruguay, 
the individual figured measuring length 10, diam. 5.1, length of aperture 
5 mm., whorls 5%. The spire is longer, and the umbilicus somewhat 
narrower. The columellar margin is broadly revolute and without fold 
or perceptible sinuosity. This form differs from that figured by d’Orbigny, 
and from the Montevideo shells examined, chiefly by having a longer spire 
and shorter aperture, the latter half as long as the shell ; by having more 
whorls, a smaller umbilicus, and by its somewhat greater size. 


Section PECTINIDENS n. sect. 
LYMN4A DIAPHANA King. 
(Plate XLVI, Figs. 3, 7, 9). 


Lymnea diaphana King, Zoological Journal, V, p. 344, No. 43, 1830. 
Limnea diaphana King, Sowerby, Conchologia Iconica, XVIII, pl. 5, 
fig. 30, 1872. 


526 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Linnea diaphana King, Strebel, Zool. Jahrb., XXV, p. 163, Taf. 8, figs. 
100@—C, 1907. 

Limnea lebrunt Mabille, Bull. Soc. Philomathique de Paris (7), VIII, p. 44, 
1883. Mabille et Rochebrune, Mission Scientifique du Cap Horn, 
Mollusques, p. 19, 1889. 

Freshwater ponds in the neighborhood of Cape Gregory (Cabo San 
Gregorio) on the north side of the Straits of Magellan, just west of the 
4oth meridian (King). Punta Arenas and Gente Grande, Lagune 
(Strebel). Punta Arenas (Mabille, for Z. Zebruntz). 

King’s type measured about 17 X 7.5mm. ; Strebel’s shells were smaller, 
10-13 mm. long, and he seems to have entertained some doubt of their 
identity with King’s. JZ. /ebruni is described as 16 to 20 mm. long, and 
agrees well with Z. daphana in other respects. It may be noted that 
Mabille and Rochebrune do not mention ZL. adzaphana, and evidently 
overlooked it. 

On the Rio Chico de la Santa Cruz Mr. Hatcher collected numerous 
Lymneas of the ZL. daphana type, some agreeing with the typical form 
- from the Straits of Magellan, others divergent therefrom. 

In what I take to be typical ZL. aaphana, from a spring on the Rio 
Chico, 15 miles above the Sierra Oveja (Pl. XLVI, figs. 3, 7, 9) the 
shell is thin, but moderately strong, narrowly rimate, rather long, the last 
whorl swollen, but mach smaller than in L. ad. inelegans, very evenly 
rounded, with sculpture of unequal growth-lines, but not malleated, and 
very glossy. The spire is Jong, slender and acuminate. The shortly 
ovate aperture is rather small; columella very narrowly revolute, not 
' adnate above, continuing free to the parietal wall above the axial crevice. 
The color is light brown, or, when the cuticle is worn off, pink, or pinkish 
white. Specimens measure: 


Fig. 3. Length 17, diam. 9.4, length of aperture 8.8 mm.; whorls 5%. 


6c 9. “ 14 66 7:25, 66 66 6.9 ai 66 5y. 
age « 6.3 mm.; whorls 4 (young shell). 
« 21.2, diam. 11, length of aperture 10.8 mm.; whorls 6. 
6c 17 66 9.8 66 66 9.4. “6 a3 5%. 
66 17.8 a3 10.4 66 a3 ine) “6 66 5%. 


In a small stream, 5 miles above Sierra Oveja, the shells are nearly 
typical in shape, but small and thin. One measures, length 11.8, diam. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 527 


6.7, aperture 6.7 mm.; whorls 5. One from near the Sierra Ventana is 
similar. 

In a pool near the Sierra Oveja the shells are similar, but darker colored, 
more olive. The apices are eroded. 


LYMN4A DIAPHANA INELEGANS subsp. nov. 
(Plate XLVI, Figs. 1, 2, 4-6). 


The shell is narrowly rimate, short and wide, the /ast whorl dispropor- 
tionately large, inflated, with sculpture of rather coarse growth-wrinkles 
and more or less malleation. The spire is small, shortly conic. Afer- 
ture very ample. Columella very indistinctly or not folded, narrow, 
nearly straight in the middle, its edge narrowly reflexed, expanding in 
the axial region. The specimens figured measure : 


Length 16, diam. 10.5, length of aperture 10.8 mm.; whorls 5. 


16 “ 9.3 “ a oy) a c 434. 
“ 16 “ 10 a) 4c 9.4 a 4 5. 
“ 15 “ 10 « “ 9.7 “ “ 434. 
“ 15.3 “ 9 “ 6 9 6 a = 


Spring on the Rio Chico, 25 miles above the Sierra Oveja (figs. 1, 2, 
4, 6). Small stream, 35 miles above Sierra Oveja (fig. 5). 

The specimens from the second locality mentioned are more regular in 
contour. Up to a length of 15% to 16 mm. the surface shows no mallea- 
tion, and at that size the shells of this lot reach maturity. The lip 
expands slightly and a very thin, white, submarginal callus strengthens it. 
In one individual growth has proceeded beyond this stage, the part added 
being strongly malleated. This shell (Pl. XLVI, fig. 5) measures, length 
17, diam. 10, length of aperture 9.8 mm.; whorls 5. 

In two of the four lots from “springs on the Rio Chico, 25 miles above 
Sierra Oveja,” there are some dwarf individuals. One measures, length 
10, diam. 6, aperture 6.5 mm.; whorls 4%. In another lot, all the shells 
are similarly dwarfed. 

In the Rio Chico, 50 miles above Sierra Oveja, a similar dwarf shell 
was taken. 

In and near drying pools on a high divide near the base of the Andes, 
50 miles north of the Rio Chico, elevation 2400 ft., the shells are very 
fragile, pale, dull buff, with strongly developed, low, wave-like costation 


528 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


and more or less malleation. One measures, length 14, diam. 8, length 
of aperture 8.6 mm.; whorls 4%. Those from the Arroyo Eke, near the 
head of Spring Creek, are also small. 

In Swan Lake (about 50 miles north of the Rio Chico) the shells are 
very delicate, almost like tissue paper, but little malleated or (usually) 
without malleation, and of a pale olive color. Most of the examples con- 
form nearly to Pl. XLVIa, fig. 2, in shape, but I have also figured the most 
elongate (fig. 1) and the shortest (fig. 3) shells. Fig. 2 measures, length 
19, diam. 11, length of aperture 10.9 mm.; whorls 434. 

Mr. Hatcher in his narrative has alluded to the abundance of shells in 
this lake (Reports of the Princeton University Expeditions to Patagonia, 
I, p. 166). The lake basin is composed of igneous rocks dammed by a 
lava flow. To the absence of calcareous material, the tenuity of the shells 
is probably due. 

Lymnea brunneoflavida Preston, Annals and Magazine of Natural His- 
tory (8), V, January, 1910, p. 110, pl. 4, fig. 1, from the Falkland Islands, 
is described as wider, more opaque and darker than ZL. daphana, alt. 14, 
diam. 8, aperture 8.75 mm. It evidently stands close to L. dzaphana. 


LYMNA PATAGONICA Strebel. 


Limnea patagonica Strebel, Zool. Jahrb., XXV, p. 164, Taf. 8, figs. 103a, 
6, 1907. 

Strebel’s types are said to differ from the form he describes as Z. 
diaphana by being browner, more of a chestnut-brown, the whorls in- 
crease more rapidly in width, the apex is commonly broken, with the 
breach closed by shell-material ; the columella stands more nearly vertical, 
and its reflection is somewhat wider, but leaves an umbilical crevice open. 
It measures as follows : 


Length 14.8, diam. 12.6, aperture 10.7 x 6.8 mm., 3% whorls remaining. 


“c 10.4, a Sale 66 Tee Ass 66 3 “c 6b 
Puerto Bridges, in a fresh-water lake. 


LYMN4A PATAGONICA RIOCHICOENSIS subsp. nov. 
(Plate XLVI, Figs. 10, 11.) 


The shell resembles Z. Aatagonica in shape, being short ovate; the axis 
is wuperforate. It is pale honey-yellow or very pale yellowish-brown. In 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 529 


an entire specimen (fig. 11) there are 3% convex and rapidly enlarging 
whorls, the last inconspicuously marked with rather widely spaced, very 
low longitudinal wrinkles, and some weak malleation in places. The 
aperture appears to be less rounded than in ZL. Jatagonica. The parietal 
and axial callus is a mere transparent film (not distinct as shown in fig. 
11), closely adnate throughout. The columella is white, solid and rounded, 
nearly straight, and without trace of a fold. The largest specimen (fig. 
II) measures : 

Length 6.8, diam. 4.8, aperture 4.9 x 3.1 mm. 

Rio Chico, 25 miles below the confluence of the Rio Belgrano, in the 
river under stones, numerous specimens. Also in a pool near the Sierra 
Oveja, one characteristic individual. 

Most of the adult examples taken are very much eroded, the spire re- 
moved, and the last whorl deeply eaten in places, as though by acid. 
The parietal callus is thick, with the outer edge distinctly raised. The 
external erosion is compensated by thickening of the shell from the inside. 
Fig. 10 measures: 

Length 5, diam. 4, aperture 4.1 X 3 mm.; 2% whorls. 

Although the perfect and the deeply eroded shells were in one lot when 
received, yet I have no doubt that they came from two sources, one of pure 
water, the other carrying CO,, doubtless from leaching through decaying 
organic matter. 


LYMN4A PICTONICA Rochebrune et Mabille. 


Limnea pictonica R. et M., Miss. Sci. Cap Horn, p. 21, 1889. 

A small, very fragile species, with exserted spire and truncate apex, 2 or 
3 convex, rapidly increasing whorls remaining. There is a very narrow 
perforation. 

Length 6, diam. 3 mm. 

Picton Island, in the southeastern termination of the Beagle Channel. 

This species seems to be decidedly narrower than the preceding. It 
may be the southern terminal member of the series of short Lymnzas 
represented in the Magellan district by Z. Aatagonica and on the Rio Chico, 
400 to 500 miles farther north, by Z. A. viochicoensts. It is quite possible, 
however, that these several forms may prove to be independent shortened 
forms, each directly related to more normal forms. 


530 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


SECTION UNDETERMINED. 


LYMN4A ANDEANA Sp. NOV. 
(Plate XLVIa, Figs. 4, 42.) 

The shell is acuminate-oblong, imperforate, very thin and fragile, pale 
yellowish-corneous, translucent. Surface dull, smooth to the eye except 
on the last part of the last whorl, where it is conspicuously malleated. 
Under the microscope the dullness is seen to be caused by extremely fine 
hair-lines, mainly longitudinal in direction, but forming a close mesh over 
the whole surface. There are also faint growth-lines and weak traces of 
spiral bands of vertical wrinkles. Whorls barely 4, the first convex, those 
following only weakly so. The last whorl has the form of a long ellipse. 
Aperture ovate. Parietal film scarcely perceptible. Columella slender, 
slightly concave, dilated above, the dilatation thin and adnate. 

Length 11.9, diam. 6.3 mm.; aperture 7.3 mm. long. 

Near the base of the Andes in drying pools on a high divide, 50 miles 
north of the Rio Chico. 

This species is apparently related to L. peregrina Clessin of southern 
Brazil and Uruguay, but differs conspicuously by the very weak develop- 
ment of spiral sculpture, that species being even more copiously striate 
spirally than the North American Z. columella. 

A few immature specimens of another thin, fragile species, probably 
related to ZL. anxdeana, were taken in small streams on the Rio Chico, 10 
and 25 miles above the Sierra Oveja. 


PLANORBIS PEREGRINUS d’Orbigny. 
Planorbis peregrinus d’Orb., Voy. dans l’Amér. Meérid., p. 348. 
Rio Negro, Bahia Blanca, etc. (d’Orbigny); lakes along the Rio Negro 


(Roca Exped.). 
PLANORBIS ANATINUS d’Orbigny. 


Planorbis anatinus d’Orb., t. c., p. 351 (Parana river, Prov. Entrerios, 
Argentina). 
Lakes along the Rio Negro (Roca Exped.). 


Family 4NCYLIDA. 


ANCYLUS CONCENTRICUS BONARIENSIS Strobel. 


A. c. var. bonariensis Strobel, Materiali, etc., p. 51, pl. 2, f. 4 (around 
Buenos Aires). 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 531 


A. c. boneriensis Strobel, Doering, Informe Oficial de la Comision cien- 
tifica agregada al estado mayor general de la Expedition al Rio 
Negro, bajo las érdenes del General D. Julio A. Roca, Zoologia, p. 


Pi Loor. 
Rio Negro near the mouth of the Rio Neuquen (Roca Exped.). 


Family CH/L/NIDA2 Dall. 

Chilinide Dall, Annals of the Lyceum of Natural History of New York, 

Px, 1870, p:357- 
CHILINA Gray. 

Chilina Gray, Specilegia Zoologica, p. 5, July 1, 1828 (for Auricula fluc- 
tuosa Gray). 

Dombeia d Orbigny, Voyage dans |’Amérique Méridionale, Mollusques, 
planche 43 (1843 ?). 

Dufplicavia Rafinesque, Atlantic Journal and Friend of Knowledge, No. 
V, 1833, p. 165 (for D. bonariensis Raf. = Chilina fluminea Maton). 

Pseudochilina Dall, Annals of the Lyceum of Nat. Hist., New York, IX, 
1870, p. 357 (for Pseudochilina limneformis Dall). 

Acyrogonia Mabille et Rochebrune, Mission Scientifique du Cap Horn, 
VI, 1889, Mollusques, p. 25. 

The apex in China differs from that of all Lymnzid snails in the initial 
half whorl of the embryo, which is tilted up, as shown in fig. 5. Growth 
of the shell seems to be upward at first, the nucleus lying below the 
summit. At the end of the third whorl, in C. f/gurata and several other 


Fic. 5. 


2 5 


\\ 


Chilina fulgurata Pils. Young specimen 3.8 mm. long, composed of 3% whorls. 


species, the color-pattern begins weakly. Previous to this the shell is 
uniform corneous-brown. The columellar fold is present at a very early 
stage, but my material does not show when it first appears. 


532 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


The growth of the shell in Patagonian species is periodic, growth-arrest 
periods being marked by streaks interrupting the normal pattern. On 
resumption of growth, the zigzag pattern is sometimes replaced by irregu- 
lar streaks; but in a later growth-period the original pattern may be 
resumed. 

The subgenus Psewdochifina was based upon a form shaped about like 
fig. 7 of Plate XLIII. The irregular or fibrous surface, which served to 
characterize the subgenus, seems to me to be wholly due to erosion, the 
cuticle or periostracum being lost from the unique type in the National 
Museum. In other characters the shell is a typical Chelina. 

Acyrogonia of Mabille and Rochebrune is a Chz/zza in which the colu- 
mellar plait is wanting. I have found this plait variable in development 
in some forms of CAz/ina from the Rio Chico. In C. fuleurata oligoptyx 
it approaches the condition described in Acyrogonza. 


DISTRIBUTION OF CHILINA. 


Chifina occupies the temperate and cold zones of South America from 
the Tropic of Capricorn to Cape Horn. No member of the group, either 
living or fossil, has been found outside of these limits.' It is noteworthy 
that no trace of the group has been found in other Austral lands— Tas- 
mania and New Zealand having sufficiently similar climatic conditions to 
favor the survival of Chz/nide, if the family ever had a wider range in 
the Antarctic area. 

Within their area, the Ciz//nzd@ are abundant snails in all suitable sta- 
tions, as Physede@ are in the north. They swarm in springs, small streams, 
lakes, and in some places the margins of rivers. They are most abundant 
southward, becoming rarer and local toward the northern borders of their 
range. 

The species from west of the Andes are in all cases, so far as we know, 
distinct from those east of the divide. In the cold temperate and cold 
zones at least, the widely diverse physical features on opposite sides of 
the Andes would lead us to expect different snail faunas. 

'Chilina olivula Repelin, Ann. Mus. d’Hist. Nat. de Marseille, VII, p. 69, of the Cenomanian 
of central France, has no columellar fold, and is clearly a Lymnzid snail with no relations what- 
ever to Chilina. Chilina in Europe, like Partula, Polygyra, Glandina, etc., is one of those myths 


of European palaontology which astonish and amuse the investigator using modern methods with 
Pulmonate snails. 


PILSBRY : NON-MARINE MOLLUSCA OF PATAGONIA. 533 


The eastern fauna, with which alone we have now to deal,! inhabits a 
comparatively arid region, poorly watered by roughly parallel streams 
flowing southeastward into the Atlantic. Each of the principal river 
systems has its own series of freshwater mollusks, in large part distinct 
specifically or racially from those of other rivers. The C/z/inzd@ of the sev- 
eral drainages have been enumerated on pp. 514-5. 


CHILINA PATAGONICA Sowerby. 


Chilina patagonica Sowb., Conchologia Iconica, XIX, pl. 3, fig. 11 (bad), 
August 1874; E. A. Smith, Proc. Zool. Soc., London, 1881, p. 845; 
Strebel, Zool. Jahrb., XXV, 1907, p. 166. 

Patagonia (Sowerby). Puerto Bridges, Picton Island and Puerto 
Montt (Strebel, various forms taken by Michaelson and Lau). 

Mr. Smith has given valuable information on this species in his paper 
of 1881. Strebel includes in it some very diverse forms, the pertinence 
of which to Jafagonica seems open to doubt. 

The specimens figured by Strebel from Gente Grande Bay, under the 
name “Chilina fluviatilis Gray,” are obviously not Chehna fluviatilis 
(Maton) of the La Plata drainage. What they are, remains uncertain. 


CHILINA AMCENA E. A. Smith. 


Chilina amena E. A. Smith, P. Z. S., 1881, pp. 37, 846, pl. 4, f. 18, 182. 
“This species is remarkable for its fragility, the slenderness of its form 
and the vividness of the markings.”’ 
Length 26, diam. 11, aperture 14.5 mm. 
Tom Bay (Coppinger). 


CHILINA FUEGIENSIS E. A. Smith. 


Chilina fuegiensis E. A. Smith, Proc. Malac. Soc. London, VI, p. 339, 
fig. vii, September, 1905. 
A very slender species, length 24, diam. 10, aperture 13.5 mm., appar- 
ently related to the preceding. 
Rio Marazzi, Useless Bay, Tierra del Fuego. 


‘Mr. E. A. Smith has published a catalogue of Chi/ina in Proceedings of the Zoological Society 
of London, 1881, to which the student is referred for information on the species of Chili. 


534 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


CHILINA FuSCA Mabille. 
Chilina fusca Jules Mabille, Bull. Soc. Philomathique de Paris (7), VIII, 
1963, (Pp. 45- 
Acyrogonia fusca Mabille et Rochebrune, Miss. Sci. du Cap Horn, VI, 
1889, p. 25. 

The shell is fragile, brownish-corneous, ornamented with a few brown 
spots ; columella white, somewhat twisted, a little thickened, but without a 
fold. Length 16 to 17, diameter 8 mm. 

Punta Arenas (Lebrun). 

This species is the type of the group 4cyvogonza’* described as a new genus 
of Chilinide@, with the following characters: ‘Shell thin but quite strong, 
the general shape acutely oval, spire projecting but not very slender; colu- 
mella arcuate, twisted but little, without the columellar folds characteristic 
of Chzfina, and descending to the base of the aperture.” 

This group is known only by the original account. Neither of the two 
species has been figured. I do not think it generically distinct from Che/na. 
In some species of that genus the columellar fold is reduced to an incon- 
spicuous vestige. } 

CHILINA NERVOSA (Mabille et Rochebrune). 


Acyrogonia nervosa Jules Mabille et Rochebrune, Mission Scientifique du 
Cap Horn, VI, Mollusques, Pt. H., p. 26 (1889). 

A more compact, ventricose species than C. fusca, with the aperture 
wider, the columella thick, arcuate, impressed in the middle and without 
a fold. Length 16, diam. 10 mm. 

Punta Arenas, in pools (Lebrun). 


CHILINA FALKLANDICA Preston. 


Chilina falklandica Preston, Annals and Magazine of Natural History 
(3), Vj January, 1910, p: 111, pliasetie-.2: 
Near C. amena. Length 15, diam. 8, aperture 9.5 mm. 
Falkland Islands. 
CHILINA STREBELI sp. nov. 
- (Plate XLIV, Figs. 24-28.) 
The shell is elliptical, with a short, conic and acute spire ; rather solid. 
Sculpture of rather coarse and unequal wrinkles along growth-lines and 
' Acyrogonia Jules Mabille et Rochebrune, Mission Scientifique du Cap Horn, VI, Mollusques, 
p- 25, 1889. 


~~ 
eee es 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 535 


minute, indistinct spiral striz. The ground-color is rather bright yellow 
on the last whorl, copiously marked with purplish-brown zigzag streaks, 
each with 4 principal angles projecting forward, and more or less 
widened at the angles. On the latter part of the whorl the streaks dis- 
appear, leaving four bands of spots. The spire is dark blue, with dusky 
brown zigzag markings on the penultimate and next earlier whorls, those 
above being uniform purplish-brown or dull blue. Whorls between 5% 
and 6, convex, regularly increasing, the last elliptical, widest in the middle. 
The aperture is nearly vertical, white, rich brown deep in the throat, 
showing the external markings as purplish-brown spot-bands. Columella 
rather broad, white, bearing a rather stout oblique fold above, a slight 
spirally entering prominence below it (in most examples scarcely showing 
in front view). Parietal callus thin, bearing a low, spirally entering fold 
at its lower third, usually hardly visible in a front view. 


Fig. 24. Length 25, diam. 14.2, length of aperture 18 mm. 


“c 25. a 25.2 “ 14.5 “c 66 18 “c 
“ 26. “ 23.5 a 13.2 « a 16 «6 
“ 24 “6 ie) “ «c 16 “c 


Mount of Observation, 40 miles south of Santa Cruz River. 

This fine species was collected in some quantity. It is distinguished 
from Chilina puelcha d'Orb. by the presence of a parietal fold, among 
other peculiarities. No other species from south of the Rio de La Plata drain- 
age has this fold developed. In the young stages (figs. 27, 28) the color- 
streaks are less distinctly defined, fading at their edges,* and the parietal 
fold is present only as a very thin whitish callus. 


CHILINA SMITHI sp. nov. 
(Plate XLIII, Figs. 1-4.) 


The shell is oblong-ovate, solid, minutely rimate, rather rudely sculp- 
tured, with wrinkles of growth and more or less distinct spiral lines ; always 
more or less deeply eroded in the adult stage. The color of the cuticle 
is olive, or in the newly-formed band behind the outer lip it is yellow. In 
adults a large part of the cuticle is wanting, exposing the calcareous layer 
beneath, which is blue and gray, or when deeply worn (as in figures 3 and 
4), itis white. The spire is worn, whorls convex, the last one azstinctly 
shouldered, compressed laterally, widest at the middle or de/ow zt. The 

‘They are represented entirely too sharply defined in figures 27 and 28. 


530 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


aperture is nearly vertical, very dark chestnut-colored within in adults, 
less dark in younger shells, fleshy-whitish near the lip-edge, which is thin 
and acute. The columella is not very wide, flat, white or flesh-tinted, 
more or less concave, and bears a rather small, very oblique fold above. 
Parietal callus very thin, transparent. 


Fig. 1. Length 41, diam. 22, length of aperture 24. mm. 
66 2. a 30 « 15.3 “ a 19 “< 
a 2: a 39.5 a 20 “6 a) 22 6 
73 4 ms 212 ‘6 19 “c m3 21.8 6c 

4c 35.2 6c 17s2 “ 66 21.6 66 


Springs on the Rio Chico, 15-25 miles above the Sierra Oveja. 

This is one of the largest species of the genus, remarkable for its solid, 
inornate shell, shouldered at the last whorl (a feature not very well shown 
in the figures), and very dark chestnut or purplish-chestnut interior. Typi- 
cally the spire is well produced, as in figs. 1, 3, but the lot contains also 
shortened forms, such as fig. 4. 

The shouldered last whorl, solidity and color distinguish this species 
from C. parchappit Orb. Italso attains a larger size. Named in honor 
of Mr. E. A. Smith, to whom we owe a very useful catalogue of the genus. 

Young shells up to 22 mm. long show faint traces of waved longitudinal 
brown streaks on the last whorl, but in older ones these disappear, though 
faintly indicated spot-bands may persist up to 30 mm. long in some 
examples. Figures 8, 9, 10 of Plate XLIII represent young shells 17.2, 
16 and 14.5 mm. long respectively. At this stage there are 5% to 6 
whorls. The spire is acuminate and the apex perfect in some individuals. 
On a yellow ground there are chestnut streaks, which show three (figs. 8, 
9) or four (fig. 10) forwardly projecting angles, with a row of spots just 
below the suture.’ 

CHILINA LEBRUNI Mabille. 
Chilina lebrunt Jules Mabille, Bulletin Soc. Philomathique de Paris, 7 
Série, VIII, 1883, p. 45 ; Mabille et Rochebrune, Mission Scientifique 
du Cap Horn, VI, Zoologie, Pt. H., Mollusques, p. 22, 1889. 

An unfigured form, probably related to C. fulgurata. Length 10 to 13 
mm., diam. 6 to 9 mm. 

Santa Cruz (Lebrun). 


‘The pattern is not very well rendered in the drawings, and the outlines of the markings are 
too definite. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 537 


CHILINA FULGURATA Sp. nov. 
(Plates XLIII, Figs. 11-15 ; XLIIIa, Fig. 4.) 


The shell is imperforate, elliptical, with short, conic spire, thin. Fully 
grown shells are in large part dull gray from loss of the cuticle on the 
back, but what remains in front is dull pale yellowish, with numerous 
dusky brown, angular streaks (fig. 15). Younger shells (fig. 11, length 12 
mm., and fig. 12, length 13.2 mm.) are densely marked with reddish-chest- 
nut, zigzag stripes ona whitish or in places yellow ground, the penultimate 
whorl with a blue ground. In an older stage (figs. 13, 14, length 16 mm.) 
_ the ground color on the back and spire is blue, but whitish at the base. 
The brown stripes have four forwardly projecting angles. The apices are 
more or less eroded in the type lot, but there are evidently not less than 
5 whorls. The aperture shows the external marking on a ground more 
or less suffused with rich light chestnut in shells not fully adult, but in 
old shells the markings are not seen, and the throat becomes chestnut, 
fading to whitish near the lip. The columella is rather narrow, white, 
straight, or only slightly arcuate, and bears a small and rather thin, very 
oblique lamella above." 


Fig. 15. Length 19, diam. 10.7, length of aperture 12.9 mm. 
“ 13-14. “ 16, ‘ 8.9, ‘c 10.9 “ 


Small stream on the Rio Chico, 5 miles above the Sierra Oveja, type 
locality ; also northward to the foothills of the Andes, in various springs 
and streams. 

This species has the elaborate color-pattern of China fuelcha 
d Orbigny, but differs from that by its comparatively narrow contour. The 
dimensions of the type of C. puelcha are, length 20, diam. 15 mm. C. 
fulgurata is probably related more closely to C. parchappi d’Orb., a 
more slender and lengthened species, deficient in color-ornamentation. 

The type of C. fuddguratfa is drawn in Plate XLIII, figs. 13, 14, and 
Plate XLIIIa, fig. 4. 

In springs twenty-five miles above the Sierra Oveja, a large, thin form 
of fulgurata was found. The elaborate color-pattern persists through 
the period of maturity, but fails in the aged or gerontic stage. The sur- 
face has minute axial pliceze and distinct spiral lines, giving it a decussate- 


‘This lamella, while correct as to outline in figures 13 and 15, is represented as more massive 
than it really is. 


538 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


granular appearance, more or less developed in different examples. The 
columella is flat, vertical, nearly straight, with a small, compressed and 
acute fold above. PI. XLIIIa, figs. 6, 6a, represent an old shell deeply 
eroded in places. Length 18 (spire largely eroded), diam. 11, length of 
aperture 13 mm. In this lot the cuticle persists over most of the surface. 

At 30 miles above the Sierra Oveja similar large shells were found ina 
spring. In even the largest, the color-pattern and sculpture persist to 
the lip-edge. Pl. XLIIIa, fig. 7, represents an area immediately below the 
termination of the suture. The shell measures, length 20.7, diam. 11, 
length of aperture 13.4 mm. The apex is eroded. 

In a small running stream on the south side of the Rio Chico, 25 miles 
above Sierra Oveja, two forms of C/z/zna were found: numerous small C. 
fulgurata, the largest 10 to 11 mm. long, and probably not fully adult; 
and three examples of a very elongate form, one of them figured in PI. 
XLIV, fig. 23. In this shell the waved streaks appear only on the last 
half of the last whorl, being preceded by two bands of small spots.* The 
columella is Lymnzid. Sculpture as in the large decussate C. fu/gurata. 
Axis rimate. Length 17, diam. 8, length of aperture 1o mm. The sig- 
nificance of these examples is doubtful. 

Small specimens which seem to be C. fve/gurafa were taken in a spring 
on the south side of the Rio Chico, seven milesabove the Sierra Ventana. 


CHILINA FULGURATA OLIGOPTYX subsp. nov. 
(Plate XLIV, Figs. 18, 18a, 20-222.) 


The shell is oval, inflated, with short but acuminate spire of between 

5 and 6 whorls. The cuticle is extremely thin and deciduous, but more 
~ or less usually remains on the face and behind the outer lip. It is corneous, 
or slightly yellowish (somewhat too yellow in figs. 20, 21, 22), with faint 
reddish-brown streaks. Where the epidermis is removed, the shell is ash 
colored, or livid purplish or fleshy, sometimes showing traces of the waved 
color-markings, the spire often dark purple (as in fig. 22a). The colu- 
mella is only moderately arched, and either has no fold (fig. 18) or a 
small fold may be seen above, in an oblique view, sometimes somewhat 
stronger than in fig. 22. The outer lip is somewhat thickened within, 
in adult shells. 


‘The scattered dots shown in fig. 23 are ferrous deposits, foreign to the shell. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 539 


Fig. 18. Length 15, diam. 8, length of aperture 10 mm. 


epee} ieee ae 12 a a me gs oo sf 
che Ted af i a 7 ae 9 se 
bl i2 Ps Sa ¢ toto Sa 
- cet Ty si gs 9 ‘ 
i Rae w o., “ 9.5 % 


Spring on the north side of the Rio Chico near the Sierra Ventana. 
Types No. 88,686 A.N.S. P. Also taken in springs 20 and 25 miles below 
the Sierra Ventana. 

By its shorter form, weak or wanting columellar fold, and the less devel- 
oped color-pattern, this race differs from C. fadgurata. Some examples 
from 25 miles below the Sierra Ventana are more fully colored, resembling 
C. fulgurata in this respect; and it may be said that dead shells which 
retain the cuticle also show the color-pattern more distinctly than living 
shells. 

CHILINA FULGURATA LIVIDA subsp. nov. 
(Plates XLII, Figs. 5-7; XLIV, Figs. 16, 17, 19.) 

The spire is /ouger than in fu/gurata, acuminate, and consisting of fully 
6% whorls; spiral striz distinct. In the adult stage the surface, where 
unworn, is “ved purplish on the back, and color-streaks are wanting or 
very weak, though one to three faint spot-bands are generally retained. 
The eroded spots have the appearance of mould, the edges under a 
hand-lens, appearing fuzzy or fibrous. The columellar fold is usually well 
developed, though often appearing weak or blunt in a face view. The 
interior is dark purplish-brown. 


Fig. 5. Length 20.5, diam. 10.25, length of aperture 12.1 mm. 


“6 6. ‘ 20 7 10 “ “ 12 ‘ 
rag 7 (a3 16 ‘ 8 «c a 9.8" “ 
cc 23.8 “ce 12.9 “c ia; 15.4 a 


Spring 15 milesabove the Sierra Oveja. Types no. 88,662 A. N. S. P. 

The young stage down to 14 mm. long, is colored like fig. 7, but occa- 
sional specimens of larger size show some faint, waved color-streaks. ° 

Another lot which I refer to “vida (Pl. XLIV, figs. 16, 17, 19) was 
taken in a small stream 5 miles above the Sierra Oveja. The half grown 
stage (Pl. XLIV, fig. 19) is elaborately zigzag-striped with reddish-brown 


1 Immature. 


540 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


on a buff ground. In older shells (figs. 16, 17) the pattern is very 
indistinct or lost by erosion. 


Fig. 16. Length 21.8, diam. 10, length of aperture 12 mm. 
“6 17 6c 18 a3 9 66 (a3 10.9 a3 
4 19. “c ina a3 6.9 6 “6 8 a3 


CHILINA FULGURATA ANDICOLA subsp. nov. 
(Plate XLIIIa, Figs. 5, 52.) 


A series of three quite young shells from under stones along a small 
running stream near the mouth of the Rio Belgrano, and a single shell, 
perhaps adult, from a spring 50 miles north of the Rio Chico, at an ele- 
vation of 1750 ft., indicate that a special race inhabits the Andean foot- 
hills, though the material at hand is hardly sufficient for its full charac- 
terization. The cuticle is rather bright yellow, with a full development of 
the /fu/gurata pattern in young shells. This pattern begins about the 
middle of the third whorl. 

In the larger shell (Pl. XLIIIa, figs. 5, 5), from the second locality, the 
ground is olive or greenish-yellow. The first half of the last whorl has 
the usual f/ewrata streaks, but the last half (following a growth-arrest 
period) has the streaks broken, leaving four spot-bands. The yellow 
ground also has many fine olive lines. The aperture is like that of 
fulgurata. The apex is eroded. Length 8.5, diam. 5, length of aperture 
6.8 mm. 

CHILINA FULGURATA HATCHERI Subsp. nov. 


(Plate XLIIla, Figs. 3, 32.) 


The shell is #72, of a dilute dull red color, variegated with four bands 
of spots, more or less indistinct, often hardly noticeable. There are also 
some obscure red-brown longitudinal streaks. The spire is darker, 
acuminate above, its surface more or less eroded. There would be over 
5 whorls if the apex were perfect. Surface glossy, with fine growth-lines 
and very delicate spiral stria, much as in C. fa/gurata from 30 miles above 
Sierra Oveja, but much more delicate. Columella straight and flattened 
below, acutely folded above, similar to large forms of C. fulgurata. 


Fig. 3. Length 19, diam. 10, length of aperture 13.4 mm. 
a 3a. 66 17.5 a 8.8 6 as pitas “c 


PILSBRY : NON-MARINE MOLLUSCA OF PATAGONIA. 541 


Arroyo Eke, near the headwaters of Spring Creek (north of the Rio 
Belgrano), April 10, 1898. 

Except on the spire, the cuticle is generally well preserved. When 
worn on the last whorl, it is deciduous along the spiral striae, which other- 
wise are hardly noticeable. These shells are readily distinguishable from 
any taken at lower levels, along the Rio Chico. 


CHILINA CAMPYLAXIS Sp. nov. 
(Plate XLIIlIa, Figs. 1-22.) 


The shell is oval, much inflated, thin. Dead individuals, but evidently 
almost or wholly unchanged in color, are light reddish-brown, with rather 
faint streaks of chestnut, which are angular and dilated to form three bands 
of sagittiform spots besides a row of small spots below the suture. These 
markings are often less fully developed than in the figured specimens, and 
they are generally removed in part by the erosion of the surface. Where 
the cuticle is retained behind the outer lip, it is yellow. The surface 
shows spiral striz more distinct than usual. The aperture is light brown 
or fulvous inside. The outer lip does not seem to be thickened within, as 
it is in C. f. oligoptyx. The columella is narrow, deeply concave, and has 
a small but distinct fold above (rarely subobsolete.) 


Figs. 1, 1@. Length 19, diam. 11.2, length of aperture13) mm. 


Dae: a tee Vt e es 12 “ 
ne 18 « Tal es TR 2EG 
ri 17 a 10.8 as a Tao. 
te 17 Be II + Be 13 ve 
ms ee II ef ps 13 4 
be ie i 1O:2 es a 12 4 


The numerous specimens vary but slightly in size or other features. 
They have some resemblance to the Magellanic C. Jatagonica, which 
however is figured as having a straight columella and a stronger colu- 
mellar fold. 

All of the specimens are ‘‘dead”’ shells. At this spring C. /udgurata 
oligoptyx was also found, both alive and among the dead shells which 
were preserved separately ; the larger individuals have the outer lip 
noticeably thickened. The shells of C. camfy/axrs differ constantly from 
the associated o/goftyx in various structural features, and must, I think, 
be regarded as specifically diverse. 


542 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


CHILINA PERRIERI Mabille. 


Chilina perrievi Jules Mabille, Bull. Soc. Philomathique de Paris (7), 
VIII, 1883, p. 46; Mabille et Rochebrune, Miss. Sci. du Cap Horn, 
VI, Pt. H., Mollusques, p. 24, 1889. 
A short, oval, solid form, apparently near C. monticola. Length 12, 
diam. 8 mm. _ It has not been figured. 
Santa Cruz (Lebrun). 


CHILINA MONTICOLA Strebel. 


Chilina monticola Strebel, Zool. Jahrb., XXV, 1907, p. 169, Taf. 8, fig. 
IOL. 

The shell is thin but rather strong, translucent chestnut, with separated, 
dilute, waved streaks, or spot bands also, mostly indistinct; comparatively 
broad, with short, acute spire of about 5 whorls. Columella has a very 
weak fold, not visible in front view. 


Length 9.8, diam. 6.9, aperture 8.4 X 3.9 mm. 
a 8.5 a 6.8 a 7.5 4 22 6 


Punta Arenas, in a large mountain lake at an elevation of about 300 
meters. 

Strebel seems to entertain some doubt as to whether this may not be 
an immature stage of C. oval’s Sowerby. I have not seen specimens. 


CHILINA MONTICOLA PILULA subsp. nov. 
(Plate XLIV, Figs. 29, 30, 302.) 


The shell is very small, shortly oval, with a very short conic spire ; 
thin; glossy when unworn, sculptured with fine growth-strize and indis- 
tinct, minute spiral lines. Adult shells are generally dull ashy- or brown- 
ish-white from loss of the cuticle, but where preserved, it is yellow or 
dusky reddish, closely marked with indistinct reddish-brown streaks, upon 
which there are spots at intervals, forming five spiral bands, one just 
below the suture, the others at subequal intervals on the last whorl. The 
longitudinal streaks are scarcely visible on some examples, and the spot- 
bands are often very faint or reduced to three. The very short spire is eroded 
in all the specimens seen, the number of whorls being therefore uncer- 
tain. The aperture is quite ample and shows the external color through 
the thin outer lip. The columella is white, rather narrow and weakly 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 543 


arcuate, having a very small and low fold close to the upper end, and 
hardly noticeable in most specimens. 

Length 5.1, diam. 3.8, length of aperture 4.3 mm. 

Springs on the Rio Chico, 25 miles below the Sierra Ventana, Feb. 15, 
1899. 

This species is known from 40 specimens in two lots, taken the same 
day in the same neighborhood, but apparently from two springs, the sta- 
tion numbers being different and the condition of the specimens as 
regards erosion slightly diverse. There is also another individual from a 
different station, “freshwater spring on the Rio Chico,” date and locality 
not given. They range in size from young shells less than 3 mm. long 
to slightly over 5 mm. Ina shell of 3 mm. there are fully three whorls. 
All the adults have the spire worn, so that the number of whorls is un- 
certain, but there are evidently four or more. 

The very globose shape of these shells shows that they are not young 
or dwarf individuals of the larger species of the same region. Moreover, 
the larger ones have the eroded and old appearance of adult snails. 
Whether the species attains greater size in the streams running from the 
springs which they inhabit remains uncertain. I know of several instances 
of dwarf snails inhabiting springs, having put at least one such case on 
record.! It is evident that the usual explanations of dwarfing in small 
quantities of water are not pertinent, since in flowing springs there is no 
lack of aération and no accumulation of the toxines of metabolism. It 
seems likely that the dwarfing of snails.in springs may be due to the 
‘purity of the water, which affords an insufficient supply of diatoms, other 
algze and vegetable food. 

This form is, for the time being, ranked as a subspecies of C/z/ina monti- 
cola from Punta Arenas, but I suspect that it is related rather to C. fulgu- 
vata. Apparently adult shells are only about half the size of sontico/a. 


CHILINA TEHUELCHA d’Orbigny. 


Chilina tehuelcha d'Orb., Voy. dans l’Amér. Meérid., p. 336, pl. 43, figs. 6, 
7; Strobel, Mat. Malac. Argent., p. 43, with var. mendozana, p. 43, 
ple 2,08. 4. 
A very obese, solid species with short spire and very large aperture. 
Length 35, diam. 25 mm. 
1 Of. Goniobasis comalensis fontinalis, Proc. A. N. S. Phila., 1906, p. 169. 


544 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Rio Negro, thirteen leagues above its mouth, in the channels formed 
by the river between the numerous wooded islands of the place called San 
Xavier, in sandy places (d’Orbigny). 

The var. mendozana Strobel is ‘smaller, the maximum length 18, 
diam. 10 mm., six-banded.”’ It is from San Carlos, province of Mendoza. 


CHILINA PUELCHA d’Orbigny. 


Chilina puelcha d’Orb., Voy. dans l’ Amer. Mérid., p. 336, pl. 43, figs. 8-12 ; 
Strobel, Mat. Malac. Argent., p. 45. 

The shell is oval, thick, yellowish-green, very rarely uniform, but gene- 
rally marked with waved longitudinal streaks, widened at their forward 
angles to form three spiral spot-bands. Columella thick, having a very 
strong fold. Length 20, diam. 15 mm. 

Rio Negro, 6 or 7 leagues above its mouth, on stones on the shores, 
very abundant (d’Orbigny). 


CHILINA PARCHAPPII (d’Orbigny). 


Limneus parchappit VOrb., Magazin de Zoologie, 1835, p. 25. 
Chilina parchappit V Orb., Voyage dans |’Amérique Meérid., p. 338, pl. 43, 
figs. 4, 5. 

An elongate, thin species, brownish, with four spot-bands, the spire 
conic and acute, whorls 5; columella typically having asmall fold. Length 
33, diam. 15 mm. 

Pampas between 38° and 39° S. lat., the typical form from the ‘“47voyo 
Salado” on the slopes of the Sierra de la Ventana, near Bahia Blanca. 
In the ‘“4rrvoyo de las Achiras” in the same region a very thin variety 
of uniform color and without a columellar fold was taken by M. Parchappe. 


CHILINA FLUMINEA (Maton). 
(Plate XLV, Figs. 35-39.) 


Voluta fluminea Maton, Trans. Linnean Soc., 1809, X, p. 330, pl. 24, 
figs. 14, I5. 

Voluta fluviatilis Maton, |. c., fig. 13. 

Chilina fluminea Gray, Spicil. Zool. p. 5; d’Orbigny, Voyage dans 
lAmér. Meérid., p. 337, pl. 43, figs. 19, 20; E. A. Smith, Proc. Zool. 
Soc. Lond:, 163i, py .643: 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 545 


Duplicaria bonariensis Rafinesque, Atlantic Journal and Friend of Knowl- 
edge, No. V, 1833, p. 165; Binney and Tryon’s reprint, p. 93. 

A short-oval, inflated shell, with usually olive ground-color, but some- 
times olive-yellow or bright green, and either unicolored or marked with 
one to five spiral bands of dark chestnut spots, alternating with spots paler 
than the ground-color. The upper bands are more persistent than those 
below. Very rarely the pattern is of irregularly zigzag streaks flowing 
from the suture down, not quite reaching the base (fig. 38). The ample 
aperture is blue-white within, and usually shows the external markings 
through. The columellar lamella is very strong, and a long entering callous 
ridge stands on the parietal wall, and is always well developed in adult 
snails. The specimens figured from San Gabriel’s Island, opposite 
Colonia, Uruguay, measure: 


Fig. 35. Length 11, diam. 7.9, length of aperture 8.9 mm. 


7) BO: “ 10.25, 4s 7 a “ 8.25 « 
ia 27 ae 12 a 8.5 “cs “ 9.9 “ 
a 38. “ 10.8 «4 7.5 “ “6 9 « 
“c 30. “ iets) “ 5.6 “ “c 6.8 “ic 


Some examples from Buenos Aires are larger, 13.25 mm. long. All 
adult shells seen have the spire eroded. 

Fig. 36 has the pattern of the type of C. fuminea. Fig. 35 is the 
color-form which Maton called ffavéatts, but it has no racial characters." 
Figures 38 and 39 are color-forms hitherto unrecorded. The spots com- 
posing the bands vary in size, and are sometimes reduced to mere dots. 

Very young shells, 2.25 mm. long, are plain colored, have no parietal 
fold, and only a very small columellar fold. With growth, the band at 
the shoulder appears first. No streaked stage precedes the bands. 

La Plata (Maton); Buenos Aires (Phila. Acad. coll.); San Gabriel's 
Island (Dr. W. H. Rush); Rio Colorado (Roca Exped.). 


CHILINA FLUMINEA MICRODON subsp. nov. 
(Plate XLV, Figs. 40-44.) 
Chilina fluminea d’Orb., Heynemann, Malak. Blatter, XV, 1868, p. 112, 
Taf. 5, fig. 11 (teeth). 
Chilina fluminea Maton, Martens, t. c., p. 184. 


'The name Voluta fluviatilis has precedence on Maton’s page, but subsequent authors have 
preferred that of fluminea. 


546 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Shell similar to /@wmnea, but differing by having the parietal lamella 
very small and deeply placed; columellar fold smaller than in /@mznea. 
The color is bright greenish-yellow, uniform or marked with 5 or fewer 
spot-bands; rarely it is brown or olive-brown. 


Fig. 40. Length 10, diam. 7.4, length of aperture 9 mm. 


ee Aale fe Bos A SF Oat tf as West Oe 
DA 2. us 1s ea 4 ct es 10 si 
SoA: es II Oy oT es os So Onns 
“44. is Il ei, 7 ms 95 


Province of Rio Grande do Sul, Brazil : Guatzbu (H. von Thering, type 
loc.); Guahyba at Porto Alegre, common on stones (Dr. Hensel). 

Professor von Martens has already referred to the differential features 
of this race, which inhabits the Jacuhy river system. 

As in C. fuminea, there is wide variation in the size and prominence of 
the spire, which may be either very short, as in figs. 40, 41, or wider and 
much more produced, figs. 42, 43. The tip of the spire is worn away in 
all the examples seen. 


CHILINA GLOBOSA Frauenfeld. 
(Plate XLV, Fig. 45.) 


C. globosa Ffld., Zoologische Miscellen, in Verhandlung derk. k. zoologisch- 
botanischen Gesellschaft in Wien, 1866, p. 13. 

According to Frauenfeld, this is a round-oval, brownish yellow shell, 
with three hardly noticeable spot-bands on the last whorl. Columellar lip 
very thick, covered with a white callus to the upper end, two-toothed. 
Length 13.8, diam. 10.2 mm. 

The example figured is larger, length 16, diam. 12.5, aperture 13.9 mm. 
long. It is straw yellow, with traces of a spot-band upon a low spiral 
angle, which crowns the last whorl. It is also stained with iron oxide in 
front and under the parietal callus. The very heavy columellar callus 
continues upon the parietal wall, bearing thick, obtuse, parietal and colu- 
mellar lamelle. 

This species is chiefly distinguished from C. fumznea by its very heavy 
parietal callus. 

La Plata States (Fild:); Ia Plata (coll-sA. N2S:7k2): 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 547 


CHILINA RUSHII Pilsbry. 
(Plate XLV, Figs. 31-34.) 

Chilina rushii Pils., Proc. A. N. S. Phila., 1896, p. 561, pl. 26, figs. 6, 7. 

This species is closely related to C. fuminea, but differs by the acute 
keel at the shoulder. This keel arises rather abruptly at the end of the 
second whorl; and either runs to the end, or after continuing for several 
whorls, gradually dies out, leaving the last whorl rounded, as in fig. 33. 
In a young shell 4.3 mm. long, with 3% whorls, the last whorl only is 
acutely carinate. 


Fig. 31. Length 14.3, diam. 9.5, length of aperture 11 mm. 


“ 32. ‘ 15.25 « II “ “ 12.8 « 
“c 33. “cc I1.5 “< 7.8 ‘6 “é 9 ‘c 
a 34. «6 14.5 a 9 “ “ ri.2 < 

“6 22.5 “a 13.5 “6 ay 16 661 


Uruguay River at Fray Bentos, Uruguay (Dr. Wm. H. Rush, U.S.N.). 


CHILINA PARVA von Martens. 


Chilina parva v. Marts., Malakozoologische Blatter, XV, 1868, p. 185. 

A small, rather thin, globose form with flat spire; brown, obsoletely 
lightning-streaked ; columella having a distinct columellar tooth and a low 
dentiform swelling below, the parietal callus distinct. 

Length 5% -6, diam. 4%-—5 mm.; aperture 4% mm. long. 

Province of Rio Grande do Sul, Brazil, at Rédersberg, in small brooks 
in the forest (Dr. Hensel). 

An unfigured species known by the original description only. 


CHILINA PORTILLENSIS Hidalgo. 


Chilina portillensis Hidalgo, Journal de Conchyliologie, 1880, p. 322, pl. 
Ed, ie: 1: 

An ovate, rather solid olive-green shell, marked with darker spiral bands 
and lines. It has columellar and parietal folds, and evidently is rather 
closely related to C. fuminea. Length 12, diam. 9 mm., length of aper- 
ture 9 mm. 

Western Argentina at Portillo, 4000 meters elevation. 


'Rush collection. 


548 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Family 4MNICOLIDA: Tryon. 


Ammnicolide Tryon, Proc. Acad. Nat. Sciences of Philadelphia, 1862, p. 
147; Gill, Proc. A. N. S. Phila., 1863, pp. 33, 35. 

Hydrobiine Stimpson, Researches upon the Hydrobiinee and Allied 
Genera, 1865, p. 4. 

Hydrobiide Fischer, Manuel de Conchyliologie, 1885, p. 723. 

This family of minute river-snails has been but little studied or col- 
lected in South America. We have some knowledge of the species of 
the Rio de La Plata system though the work of d’Orbigny, Doering and 
Strobel and collections made by Dr. W. H. Rush, U.S.N. In south- 
ern Brazil Dr. von Ihering has done good work, though hampered by 
the want of La Platan material for comparison. In Ecuador kK. Miller 
has described a few forms collected by Wolf and others. In the north, 
Dr. von Martens has recorded a few Venezuelan species. None are 
known from the Orinoco or Amazon systems. Through the collections of 
Mr. Hatcher we are now enabled to add several forms from Patagonia. 
The opportunity has also been taken fully to describe and figure the 
known species of Pofamolithus, part of them new forms, most of the rest 
hitherto defined only by a brief “key” published in 1892. Only six of 
the thirty species now known have hitherto been figured. 

All of the South American genera and species of Amzzcolide are de- 
scribed or referred to below. 

The following genera of this family are represented in South America: 


Ammnicola Gould and Haldeman, Idiopyrgus Pilsbry, 
Littoridina Souleyet, Potamolithus Pilsbry, 
Potamopyrgus Stimpson, Lithococcus Pilsbry. 


Of these genera, mmnzcola has been found only in the extreme north. 
A. ernesti (Martens) of Lake Valencia, Venezuela, is closely related to 
A. panamensis Tryon and several Mexican species, and is undoubtedly 
of North American origin. * 

Potamopyrgus is the dominant genus of 4mnicolide in New Zealand 
and Tasmania. It is unknown in the Oriental region. In America it 
extends from Argentina to Venezuela, through Mexico to central Texas 
and throughout the West Indies. This distribution is explicable on the 

' Hydrobia (Amnicola) ernesti Martens, Die Binnenmollusken Venezuelas, 1873, p. 209, Taf. 2, 


fig. 12. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 549 


supposition that the genus had its origin in Antarctica, or one of the 
Austral lands once connected therewith. 

Littoridina resembles the Holarctic Paludestrina and the genus /luvio- 
pupa* of Australia and the Melanesian Plateau, but until the external 
genitalia of all can be compared, no well-founded opinion of the affinities 
of these genera can be formed. 

Ldiopyrgus is an Archhelenic genus, if my estimate of its affinities is 
correct. 

The affinities of Lz¢hococcus are uncertain. 

Potamolithus, in the form of the shell, closely resembles the genera 
assembled by Tryon in the subfamily Lethoglyphine: Fluminicola of 
western North America, Lithoglyphus of eastern Europe, Pachydrobia, 
Lacunopsts and Fulhenta of Indo-China. All of these genera differ from 
Potamolithus by the small number and large size of the cusps of the outer 
marginal teeth.” /7Zwmznzcola has male genitalia of widely different form. 
The genus Pefterdiana of Tasmania and Australia has a strong globular 


Petterdiana tasmanica (Tenison-Woods), half row of teeth and an isolated outer marginal tooth. 


shell, with wide columella, similar to the primitive species of Pofamolithus. 
The radula, hitherto undescribed, has the formula £5. 2, 1, 5. 20. 25 


Zz 


(Fig. 6, teeth of a half row, and a detached outer marginal tooth). This 


' Fluviopupa n. gen., type F. pupoidea (Mousson) of Fiji. The teeth are of the usual shape in 
Amnicoline, central with the cusp formula %*}, admedian with 10 subequal cusps, marginals 
with about 30, those of the outer marginal very minute. Shell pupiform, with obtuse summit 
and convex sides, the aperture ovate, vertical or sloping forward below, the long parietal margin 
straightened. Operculum thin, with nucleus near the base. Penis unknown. /ydrobia petterdi 
E. A. Smith seems to be congeneric, judging from specimens sent from Manaro, N. S. Wales, 
by Dr. J. C. Cox. These shells have the appearance of the European Aythinelle, but differ 
from them in dentition. 

* See J. Poirer, Journal de Conchyliologie, XXIX, 1881, pp. I-19. 


550 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


radula resembles that of Pofamolithus in the important character of having 
many minute cusps on the marginal teeth, more than double the number 
of those on the admedian tooth. It differs from Pofamolithus by having 
a single basal cusp or denticle on each side of the central tooth, Pofamo- 
fithus having two or more. I have found the number of basal cusps so 
variable in many genera that I do not attach much importance to this 
character. Of all known genera, Pefferdiana is, in my opinion, the most 
closely related to Potamolthus. 

Marginal teeth with a small number of cusps characterize the subfamily 
Lithoglyphine. The Austral genera Potamolithus and Petterdiana cannot 
be included in this subfamily. They may for the present be placed in the 


Amunicoline. 
LITTORIDINA Souleyet. 


Littoridina Souleyet, Voyage autour du Monde exécuté pendant les années 
1836 et 1837 sur la corvette La Bonite, Zoologie, II, p. 565 (1852). 
Monotypic: type ZL. gaudichaudit Soul. 

“Littorinida Eydoux et Souleyet”’ Stimpson, Researches upon the Hydro- 
biinze, etc., 1865, p. 43; Fischer, Manuel de Conchyliologie, 1885, 
P- 739: 

Paludestrina in part, d’Orbigny, 1839; Stimpson, 1865. 

Fleleobia Stimpson, Researches upon the Hydrobiinz, etc., 1865, p. 47. 
Monotypic: type P. culminea. 

FIydrobia and Paludina of some authors. 

The shell is small, very narrowly rimate, acutely ovate, thin, smooth 
or rarely striated spirally, of olive or pale corneous color; whorls usually 


Fic. 7. 


Littoridina guadichaudit, anterior part of the body, the pallial cavity opened and spread to the 
left. a@, anus ; Pen., penis. (After Souleyet.) 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 551 


but slightly convex, rarely carinate; aperture ovate, not very oblique, less 
than half as long as the shell; peristome thin and simple, continuous or 
interrupted. The operculum is thin, ovate, paucispiral, the nucleus below 
the lower third and near the columellar margin. The long penis has 
several digitate lateral papillae or simple warts, and is curved at the end. 
The central tooth of the radula has one to four basal denticles on each 
side. The marginal teeth have very numerous denticles, more than twice 
as many as the admedian tooth. The animal is oviparous. 


DENTITION OF LITTORIDINA. 


Littovidina guadichaudit, the type of the genus, has several, probably 
four, basal denticles on each side of the central tooth. Souleyet’s figure 
shows five, but allowance must be made for the difficulty of the object and 
the date, 1852. 

Dr. von Ihering found two basal denticles on each side in ZL. australis. 
For L. piccum he gives the number ~2; and ZL. charruana *.. 


L. simplex of the Rio Chico (fig. 8) has a central tooth with the cusp- 


Fie. 8. 


Central tooth of Lzttoridina simplex Pils. 


formula <8. The admedian tooth has 6, 1, 6 cusps, the two marginal 
teeth many, about 30, cusps. 
L. hatcheri, Rio Chico, has the cusp formula ;2;. 8.25.30. The cusps 


of the marginal teeth are so excessively small that their exact number is 
not certain (fig. 9). 


Teeth of Littoridina hatcheri Pils. 


Littovidina was based upon a snail from the river of Guayaquil, having 


552 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


a shell resembling Paludestvina or Bythinella, but differing by the penis, 
which is not bifid, and has several lateral papillze or warts. 

We owe to Souleyet an excellent account of the anatomy of L. guadt- 
chaudit, and Dr. von Ihering has published valuable notes on that of 
several species of southern Brazil. Many other species are referred to 
Littortdina from the resemblance of the shells and their distribution alone. 
Most of them have been described under genera based upon European 
types, such as Paludestrina and Hlydrobia, which, so far as we know, differ 
anatomically from the type of Lz/forzdina. Provisionally, therefore, we 
refer to Lefforidina all of the smooth, slender and thin oviparous Amni- 
colinze of South America, having the lip simple. 

Most of the species are fresh-water forms, but a few live as well in the 
brackish water of estuaries, or even in the salt water of sheltered bays. 
They are known to extend from below the mouth of Santa Cruz River in 
Patagonia north to Ecuador in the west, and to the state of Rio Janeiro, 
Brazil, in the east. 

Many species of Lz¢foridina have been described from the La Plata sys- 
tem and the Sierras of western Argentina (Provinces of Cordoba and Men- 
doza) by d’Orbigny,! Strobel? and Doering,’ but none have heretofore been 
reported from the southern territories. Mr. Hatcher’s collections extend 
the range of the genus south to the Mount of Observation, below the 
mouth of the Santa Cruz River. 

Several species of Lzfforidina have both slender and stouter forms, 
with others of intermediate shape, in any large lot. These differences 
may be sexual, but no observations bearing on the point have been made. 
In some other species the contour is nearly uniform. 

Various authors having referred the Littoridinze to d’Orbigny’s Padlu- 
destrina, it may be well to give some account of that genus. 

Paludestrina was proposed by A. d’Orbigny in 1839* for Paludina 
acuta of France and the South American rissoids of fresh and brackish 
water, having the operculum spiral, such as P. dapzdum, P. peristomata and 
P. australis. Various subsequent authors have mentioned or discussed 

‘Alcide d’Orbigny, Voyage dans I’Amérique Méridionale, Mollusques, 1839. 

*Pellegrino Strobel, Materiali per una Malacostatica di terra e di acqua dolce dell’ Argentinia 
Meridionale. Pisa, 1874. 

*Adolfo Doering, Apuntes sobre la fauna de moluscos de la Republica Argentina, in Boletin 


de la Academia Nacional de Ciencias en Cordoba, VII, 1884, pp. 465-474 (“Alydrobia”’). 
* Voyage dans l’Amérique Méridionale, Mollusques, p. 381. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 553 


the group, but no type species seems to have been selected until William 
Stimpson, in 1865, selected P. awberiana A Orb. as type.’ Bourguignat 
in January, 1887, named P. acuta Drap. as type of the genus.” In 1895 
Dr. von Ihering proposed to restrict Pal/udestrina to the group now called 
Potamolithus, with P. peristomata as type.* This course cannot be fol- 
lowed because of Bourguignat’s earlier selection. /. aczfa (Drap.) must 
stand as the type of Paludestrina. 

The following names will fall as synonyms of Paludestrina: Littori- 
nella Braun, 1846, type L. acuta (Drap.). crobta Stimpson, 1865, type 
Turbo minutus Totten. The preceding live in brackish water, or in 
sheltered bays or estuaries, or sometimes where the water is fresh. 
The exclusively fresh-water groups By/iinella Moq., 1851, type B. viridrs 
Mogq., and S#mpsonia Clessin, 1878,* type B. wckliniana (Lea), are in- 
distinguishable from Pa/udestrina in shell, operculum and dentition, but 
according to Moquin-Tandon the penis of &. ferrusina is bifid, while 
that of P. mznuta (Totten) was found to be simple by Stimpson. Until 
the types of these proposed genera are studied and the forms of their 
penes ascertained, there seems to be little reason for recognizing more 
than one genus of these slender Amnicoloid snails in North America and 
Europe, although it is likely that several may ultimately be defined. 

In Paludestrina (including Bythinela) the central tooth has a single 
well-developed basal denticle on each side, but often a second one is 
weakly developed. 

LITTORIDINA HATCHERI Sp. Nov. 
(Plate XLII, Figs. 7, 7@, 8, 11-13.) 


The shell is minute, imperforate (though slightly rimate), rather solid, 
olivaceous brown, smooth; in shape ovate or somewhat pupiform. The 
outlines of the spire are convex; the summit minute, a little obtuse, 
though the apex is not depressed. Whorls 4, convex, at first slowly, then 
rapidly widening, the suture therefore descends more rapidly and 
obliquely in its last volution, and it is also deeper than in those preceding. 


‘Researches upon the Hydrobiine and allied forms, Smiths. Misc. Coll., No. 201, pp. 45, 46. 
This selection was not valid for the reason that azberiana was not one of the species included 
in Paludestrina in d’Orbigny’s original publication, but was added some years later. 

2 Etude sur les noms génériques des petites Paludinées 4 opercule spirescent, pp. 9, 10. 

3 Die Gattung Paludestrina, in Nachrichtsblatt d. d. Malak. Gesellschaft, XXVII, 1895, pp. 
122-128. 

*Malak. Blatter, XXV, 1878, p. 151. 


554 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


The last whorl is rounded and expands towards the aperture, at the upper 
angle of which it descends slightly. The aperture is subvertical, sym- 
metrically ovate, narrower but not angular above. The peristome is con- 
tinuous, of a deep reddish brown color, almost black at the edge. The 
outer margin is slightly thickened and obtuse ; the inner margin is rather 
heavily calloused, forming a raised ledge across the preceding whorl, 
from which it is slightly detached above and below. 

Length 2.25, diam. 1.2 mm.; length of aperture 1.1 mm. (Pl. XLII, figs. 
7, 7). 

Rio Chico de la Sta. Cruz, Territory of Santa Cruz, Argentina, from 
below the mouth of the Rio Chalia to the mouth of the Rio Belgrano ; 
and northward along the eastern slope of the Andes 65 miles, in springs 
and small streams. Specimens were taken at the following localities : 
Spring on the Rio Chico below the mouth of the Rio Chalia (2: 12: ’99) ; 
spring on Rio Chico, 25 miles below Sierra Ventana (type locality) ; 
twenty miles below Sierra Ventana, ina spring; north side of Rio Chico 
near Sierra Ventana; Rio Chico, 40 miles above Sierra Ventana; small 
stream 5 miles above Sierra Oveja; small stream on south side of Rio 
Chico, 50 miles above Sierra Oveja ; near the mouth of Rio Belgrano; Rio 
Blanco, base of the Andes; spring 50 miles north of Rio Chico, elevation 
1750 ft.; spring near base of the Andes, 65 miles north of the Rio Chico, 
elevation 2400 ft. Also several lots from springs on the Rio Chico with- 
out exact location. 

This small snail is evidently abundant in springs and small streams 
along the whole course of the Rio Chico de la Sta. Cruz. It is apparently 
related to L. kuestert and especially to L. &. cordillere (Strobel),' from the 
Province of Mendoza, but differs from these by its wider, convexly conic 
spire, the shape of Z. atchert being rather pupiform, whereas the spire is 
strictly conic in L. Auestert and cordillere. 

L. hatcher?t varies within wide limits in nearly all of the colonies col- 
lected. This variation is chiefly (1) in size, nearly every lot consisting of 
both large and small individuals, the difference being greater than I have 
ever observed in North American Amuzicolide,; and (2) in the degree 
of descent, lateral deviation or uncoiling of the last whorl. As type I 
have selected a shell nearly normal in shape, Pl. XLII, figs. 7, 7a, 2.25 


‘Hydrobia kiisteri and var. cordillere Strobel, Materiali per una Malacostatica di Terra e di 
Acqua dolce dell’Argentinia Meridionale, p. 61. Pisa, 1874. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 555 


mm. long. Some others in the same lot are smaller and more pupiform, 
with the parietal callus barely free from the preceding whorl, as in fig. 8, 
length 1.7mm. The entire lot from the type locality consists of shells 
which do not depart much from the normal Lz//orzdina contour. 

At two stations, 40 and 50 miles above the Sierra Oveja, a considerable 
proportion of the shells have the last whorl deeply descending to the aper- 
ture and becoming free, or partially free near the termination. A series 
from 40 miles above Sierra Oveja is figured, Pl. XLII, figs. 11, 11a, 12, 
13. Fig. 12 represents a nearly normal shell; figs. 11, 11@ and 13, 
those with the last whorl loosening its coil; all are fully mature, but not 
old snails. The individuals figured measure: 


Fig. 11. Length 3.3, diam. 1.7, length of aperture 1.2 mm.; whorls 434. 


“c 12. “ alg) “ 1.6 “ “ 1.25 66 “c 4%. 
“e 12: ce 2.1 “c 1.3 “ce “cc I “ce “c 4%. 


The same tendency is well-marked ina lot from far down the river, 
below the mouth of the Rio Chalia. The other lots of the species resemble 
the type lot, having the shape nearly normal, but with a variable proportion 
of individuals in which the peristome is partly or for a short distance free. 

L. hatcheri is thus a species distinctly aged or gerontic, with this feature 
much more strongly emphasized in certain colonies. 


LITTORIDINA SIMPLEX Sp. Nov. 
(Plate XLII, Figs. 9, 10.) 


The shell is minutely rimate but scarcely perforate, rather thin, ovate- 
conic, of a very pale olivaceous-yellowish tint, the apex and first whorl 
reddish in the type lot, smoothish, but lightly marked with growth-lines. 
The spire is straightly conic, the apex minute and very slightly obtuse. 
Whorls 4%, all rather strongly convex, regularly enlarging, and joined 
by an impressed suture, which on the last whorl or two shows a narrow 
faint margination below caused by transparence. The aperture is ovate, 
subvertical. Peristome continuous, its edge delicately marked with a 
brownish line. The outer lip curves forward a little in the middle, and 
has a very delicate whitish thickening within. Inner margin thickened a 
little, continuous, in contact with the preceding whorl. 


Fig. 9. Length 3, diam. 1.8 mm., length of aperture 1.3 mm. 
e 10 ae 3 ae > “e ae ae I 5 ‘e 


556 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Springs along the Rio Chico de la Sta. Cruz, at the following places: 
About 15-20 miles above the mouth of the Rio Chalia; springs 20 and 
25 miles below the Sierra Ventana; spring near the Sierra Ventana (type 
locality); 25 and 50 miles above the Sierra Oveja. Also near Mt. of 
Observation, on the coast, below the mouth of the Santa Cruz River. 
Also at the foot of the Andes, 50 miles north of the Rio Chico. 

This species resembles several forms of the Rio de La Plata system, but 
is distinguished by the combination of quite strongly convex whorls and 
a continuous peristome; its inner margin, though not much thickened, yet 
forms a distinct ledge across the preceding whorl. The striation is exag- 
gerated in fig. 9, and the umbilical chink is represented too wide and 
prominent in both figures. The apex is reddish in the type lot, but not 
in others. JZ. s¢mplex occurs in the same springs with ZL. “afcheri along 
the Rio Chico, but it is apparently less abundant and it does not seem to 
ascend the river so far. 


LITTORIDINA SUBLINEATA sp. nov. 
(Plate XLVIa, Figs. 5, 52.) 


The shell is imperforate, ovate-pyramidal, thin, light brown. Surface 
faintly marked with growth-lines, and on the last half of the last whorl 
there are several (four or five in the type specimen) very low spiral cords, 
grouped in the peripheral region. The spire is rather straightly conic, 
the summit a little obtuse, the apex rising but little above the level of the 
first whorl. Whorls 5, convex, the last very indistinctly angular below 
the periphery, causing the base to appear slightly flattened. The aperture 
is ovate, very slightly oblique; peristome thin and acute, the outer margin 
not darkened or thickened. Columella concave, slightly thickened, con- 
tinued in a thin adnate callus across the parietal wall. 

Length 3.6, diam. 2.2 mm., length of aperture 1.5 mm. 

Small stream on the Rio Chico, 35 miles above the Sierra Oveja (type 
locality) ; also in a spring 25 miles above the Sierra Oveja, and in a “big 
spring on the Rio Chico,” the exact location of which was not noted on 
the collector’s label. 

It sometimes attains a larger size than the type, a shell from the second 
lot noted above being 5.4 mm. long with 5% whorls. This species differs 
from L. sémplex by its weakly subangular periphery, marked with a few 
spiral lines, the less prominent parietal callus and fragile outer lip. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 557 


LitToRIDINA AUSTRALIS (d’Orbigny). 
(Plate XLIc, Figs. 3-8.) 


Paludina australis VOrb., Mag. de Zool., 1830, p. 30. 

Paludestrina australis V Orb., Voyage, p. 384, pl. 48, figs. 4-6 (Bahia Blanca 
and Bahia de San Blas, Patagonia, on water plants and mud covered 
by each tide; also at Montevideo); von Ihering, Nachrichtsblatt, 
XXVII, 1895, p. 123, anatomy (Rio Grande do Sul and Sao Paulo) ; 
von-Martens, Malak. Blatter, XV, 1868, p. 192 (Porto Alegre). 

Melania dubiosa Clessin. 

d’Orbigny gives the dimensions, length 6, diam. 3 mm., whorls 7. Fig. 

7, drawn from a specimen from Bahia Blanca, the type locality, is of this 

size. Some examples are narrower (fig. 6), and others much larger, length 

8.5 mm. (fig. 5). The whorls are almost flat except in the largest shells, 

where the last whorl is convex. Under a strong lens very faint spiral 

striz may be seen on most examples. Figures 5-7 represent bleached 
shells from Bahia Blanca, the type locality, received from Dr. von 

Ihering. 

At Montevideo, in a creek in the Prado, the shells taken by Dr. Rush 
are large, olivaceous, with noticeably more convex whorls. They measure : 


Length 8.3, diam. 4, length of aperture 3.5 mm.; whorls 8. 


4s 8.2 as 2.0 4 a 22 “ as 7%. 
“c 8.4 ‘6 3.9 “ 6c 2.3 “c “ 8%. 


In a small spring back of the Cerro, Montevideo, the shells are similar 
but smaller, about 5 mm. long with 6% whorls. 

Shells from Rio Grande do Sul, sent by Dr. von Ihering, are about 6 
mm. long, 2.3 to 2.9 mm. in diameter. The more slender shells are less 
numerous than the stouter ones, and some are transitional in’shape. The 
color varies from dark to pale olive (Plate XLIc, figs. 3, 4, 8). A small 
form has been sent also from Ilha Comprida, near Iguape, on the Sao 
Paulo littoral. 

Melania dubiosa Clessin, judging from specimens sent from S. Leopoldo, 
State of Rio Grande do Sul, by Dr. von Ihering, is identical with the 
large form of Z. australis noticed above from Montevideo. 


5538 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


LITTORIDINA CHARRUANA (d’Orbigny). 
(Plate XLIc, Figs. 1, 2.) 

Paludestrina charruana dOrb., Voy., p.. 384, pl. 75, figs. 1, 2 (at the 
embouchure of a stream into the sea north of Montevideo); von 
Ihering, Nachrbl., 1895, p. 123, anatomy (Iguape, Sao Paulo). 

A shorter, stouter snail than Z. azstvalis, the cuticle olive, with black 
growth-arrest lines in old shells. It varies widely in shape, as may be 
seen by figs. 1, 2, which represent average, stout and slender shells from 
the Rio Cubatao, near Santos, State of Sao Paulo. They measure : 

Length 5.8, diam. 3.5, aperture 2.6 mm.; whorls 6. 
ge any: ee eaey Syed 2B et ey 
¢ 5 a2 as 2224 

It has also been sent by Dr. von Ihering from the Ribeira at Iguape 
and from Guatzbu, State of Rio Grande do Sul, where the shells are more 
slender. 

d’Orbigny’s type measured, length 5, diam. 3 mm., whorls 6. 


LITTORIDINA PIciIUM (d’Orbigny). 
(Plate XLIc, Fig. 13.) 


Paludina picium d’Orb., Mag. de Zool., 1835, p. 30. 

Paludestrina picium d’Orb., Voyage, p. 383, pl. 47, figs. 17-21 (Rio de La 
Plata at Buenos Aires, etc., under stones); von Ihering, Nachrbl., 
1895, p. 123, anatomy (Rio Grande do Sul); von Martens, Malak. 
Blatter, XV, 1868, p. 192 (Rddersberg). 

This is smaller and thinner than ZL. chavruana, less opaque, of a paler 
greenish yellow or olive-corneous tint. The whorls are rather strongly con- 
vex, the suture well-impressed, having a grayish border below. d’Orbigny 
gives the size as length 3, diam. 2 mm., whorls 5. Two from San 
Gabriel’s Island, in the Rio de La Plata off Colonia, Uruguay, measure: 

Length 4, diam. 2.2, aperture 1.8 mm.; whorls 6. 
Noe Sane OE Ne Beene 12° f iiatoy, 0% 1. oe 

Specimens are before me also from the type locality, Buenos Aires, 
agreeing fully with those figured. 

Littoridina glabra (Tryon) from Bolivia resembles Z. picium, but it is 
somewhat more slender, thinner, the columella less calloused. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 559 


LITTORIDINA BERTONIANA Sp. Nov. 
(Plate XLIc, Fig. 9.) 


The shell is barely perforate, oblong-turrite, pale olivaceous, the length 
about double the greatest diameter, and two and one-half times the length 
of the aperture. Spire rather straightly conic, the apex obtuse. Whorls 
5%, moderately convex, the last well rounded. Surface delicately marked 
with very fine spiral striae, usually strongest on the penultimate whorl. 
The aperture is ovate, angular above. Peristome thin and simple, contin- 
‘uous, the columellar margin narrowly expanded. 

Length 3.6, diam. 1.7, length of aperture 1.4 mm. 

Puerto Bertoni, Paraguay. Types No. 103,045, A. N.S. Phila., from No. 
244 of the Museu Paulista, collected by A. de W. Bertoni. 

This species differs from Potamopyrgus peteningensts (Gld.) by its much 
less convex whorls, smaller size and minute spiral striae. Pofamopyrgus 
scottit has far more convex whorls and coarser sculpture. 

In some specimens from the type locality the spiral striae are extremely 
minute and weak, yet visible under the compound microscope. These 
were sent under No. 190 Museu Paulista. 

A few other species at present referred to L/loridina, suchas L. pedrina 
Miller, have spiral sculpture ; yet the presence of this unusual feature raises 
some doubt as to the genus, which can be definitely determined only by 
examination of the genitalia. ZL. dervtontana may prove to belong to 
Potamopyrgus. 


OTHER SPECIES OF LITTORIDINA DESCRIBED FROM SouTH AMERICA, 
SOUTH OF THE EQUATOR.? 


LITTORIDINA ISABELLEANA (d’Orbigny). Pad/udestrina isabelleana a’ Orb., 
Voy,., p. 385, pl. 75, figs. 4-6. 3X1 mm., whorls 6, flat. Ina stream 
near Montevideo and in the Bay of Montevideo at the contact of fresh 
and salt water. 

LitTORIDINA PARCHAPPII (d’Orbigny). Paludina parchappii d’Orb., t. c., 
p. 30; Paludestrina parchappit ad Orb., Voy., p. 383, pl. 48, figs. 1-3. 
6.5 X3 mm. with 7 very convex whorls; whitish, aperture not angu- 

‘ This list is believed to be a complete catalogue of the genus up to the end of 1909. Palu- 
dina brunnea and P. conica Anton, Verzeichniss, 18 39, p. 52, South America, and Budimus palu- 


dinoides, Ibid., p. 42, are probably Littoridinz, but the descriptions are totally inadequate and 
the names should be deleted from the list of species. 


560 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


lar posteriorly. Streams in the pampas south of Buenos Aires as 
far as Bahia Blanca, especially in the Rio Salado and Arroyo Salado 
in 30° S. lat. Aydrobia parchappi Doering, Bol. Acad. Cienc. Cor- 
doba; WIT, 472: 

LITTORIDINA KUESTERI (Strobel). AZydvobsa kiistert Strobel, Mater. 
Malac. Argent., 1874, p. 61, pl. 2, fig. 6. 42.5 mm., 5 whorls, 
to 3.5 X 2-2.5 mm. San Carlos ed Aguanda, province of Mendoza, 
in stagnant water. //ydvobia_ kiistert var. cordillere Strobel, t. c., 
p, 61, pl: 2, fig. 7. 30¢1.5—-2.5| x Des ymms, 42% awions Sick 
de Mendoza. 

LITTORIDINA AMEGHINI (Doering). Hydrobta ameghini Doering, Bol. 
Acad. Cienc. Cordoba, VII, pp. 466, 469. 7-9 X 3.5-4 mm., whorls 
7%. Pampean formation, Lujan, Argentina. 

LITTORIDINA OCCIDENTALIS (Doering). A/ydrobia occidentahs Doering, 
tC, pp. 466, 471. 62.7 mm., whorls 6, “San Wuis; Mendoza; 
San Juan, Santiago, Argentina. 

LITTORIDINA MONTANA (Doering). Hydvobta montana Doering, t. c., 
pp. 467, 473. 4.52 mm., whorls 6. Sierras de Cordoba and S. 
Luis, Argentina. 

LITTORIDINA GLABRA (Tryon). ydvobia glabra Tryon, American Jour- 
nal of Conchology, I, p. 222, pl. 22, f. 12. Bolivia. 

LITTORIDINA CUMINGII (d’Orbigny). Paludina cumingi d’Orb., Mag. de 
Zool., 1835, p. 30. Paludestrina cumingi A Orb., Voy., p. 385, pl. 47, 
figs. 14-16. 6X2 mm., whorls 6. In fresh-water streams near 
Callao and at Valparaiso. 

LITTORIDINA ATACAMENSIS (Philippi). Paludina atacamensts Philippi, 
Reise durch die Wiiste Atacama, 1860, p. 185, Taf. 7, fig. 15. Length 
1% lines, whorls 5. Tilopozo, Chili, in about 23°, 20 S. lat. 

LITTORIDINA POPOENSIS (Bavay). Paludestvina popoensis Bavay, Bull. 
Soc. Zool. France, 1904, p. 154, fig. 5. Conic, 5 X2.5-3.5 mum., 
with 6 to 7 rounded whorls. Lake Popo, Bolivia. 

LITTORIDINA CUZCOENSIS n. sp. (figs. 10, 11). The shell is minutely 
perforate or rimate, thin, corneous-white, smooth and glossy. Spire 
straightly conic, whorls 6, moderately convex, the last evenly rounded. 
Aperture ovate, slightly oblique. Peristome thin and simple. 


Fig. to. Length 4.9, diam. 2.5, length of aperture 1.8 mm. (typical). 
ee ASO yeh e252 if 1.6 ‘ (slender phase). 


PILSBRY : NON-MARINE MOLLUSCA OF PATAGONIA. 561 


Cuzco, Peru (H. von Ihering). 
This species evidently stands close to L. Jofoensis Bavay, of the saline 
Bolivian Lake Popo; but the spire seems to be of a more turrite shape, 


FIG. 10. 


the last whorl comparatively shorter in L. Aofoensés, which moreover belongs 

to a different drainage. 

Compared with Z. cu/minea of Lake Titicaca, this species differs by the 
less attenuate spire and fewer whorls. Z. cawzcoens@s is not very closely 
related to the Titicaca species. 

LITTORIDINA NEVENI (Bavay). Pyrgula nevent Bavay, Bull. Soc. Zool. 
France, 1904, p. 155, fig. 6. Last three whorls strongly carinate. 
53mm. with 6% whorls. Lake Titicaca. 

LITTORIDINA ANDICOLA (d’Orbigny). Paludina andicola dOrb., t. c., p. 
29. Paludestrina andicola @’ Orb., Voy., p. 385, pl. 47, fig. 13. Bavay, 
Bull. Soc. Zool. France, 1904, p. 153, fig. 2.5 8X3 mm. with 8 flat 
whorls, the last acutely carinate. Lake Titicaca. 

Littoridina andicola, ecarinate form : Paludestrina culminea d Orb., Voy., 
p-. 386, pl. 47, figs. 10-12. 6X3 mm., whorls 7, somewhat convex. 
Lake Titicaca. 

Some specimens of the ZL. cau/minea type, collected by A. Agassiz in 
Lake Titicaca, are subangular at the periphery, and therefore somewhat 
intermediate between L. cu/minea and L. andicola. Bavay has figured a 
series of shells showing the intergradation of these supposed species. 
LITTORIDINA GUADICHAUDII Souleyet, Voyage la Bonite, Zoologie, II, p. 

565, pl. 31, figs. 31-33 (living animal, shell and operculum), pl. 32, 
figs. 9-19 (soft anatomy). 5X3 mm., 6 whorls. River of Guaya- 
quil, Ecuador. 

LITTORIDINA ECUADORIANA (Miller). Paludestrina ecuadoriana Miller, 


562 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Malak. Blatter, mn. F:, 1.1670; ps 153, Vales 3, «7 aoa 
whorls 6. Guayaquil River, Guayaquil, Ecuador. 

LITTORIDINA BOETZKEsS!I (Miller). Paludestrina boetzkest Miller, t. c., p. 
155, laf. 8, fig. 4. 4.52.4 mm., whorls 6%. S. Domingo and 
Guayaquil River, Ecuador. Cf L. guadichaudit. 

LITTORIDINA (?) PEDRINA (Miller). Zydvobia pedrina Miller, t. c., p. 155, 
Taf. 6, f. 7. 3.5 X1.5 to 4X1.8mm., 5% to 534 whorls. Micro- 
scopically granulose. Rio Pedro in the Chillo valley, Ecuador. 


POTAMOPYRGUS Stimpson. 


Potamopyrgus Stimpson, American Journal of Conchology, I, 1865, p. 53; 
Researches upon the Hydrobiinze, Smiths. Misc. Coll. No. 201, p. 49. 
Monotypic; type, Aelania corolla Gld. 

Lyrodes Doering, Bol. Acad. Nac. Ciencias Cérdoba, VII, 1884, p. 461. 
Type L. guaranitica. 

Pyrgophorus Ancey, Bulletin de la Société Malocologique de France, V, 
1888, p. 192. Type, Pyxgulopsis spinosa C. & P. 

Fluttonta Johnson, Proc. Royal Society of Tasmania for 1890, p. 90 
(1891). Type, Potamopyrgus corolla. 

Amnicolinz with rather slender, thin, rimate shells of ovate-conic or 
turrited contour, often armed with a row of spines on a delicate keel at 
the shoulder of the last whorl or two. They differ from other American 
genera in being viviparous. 

Besides the following species, P. coronatus Pfr. is known from Baran- 
quilla, Colombia, and Lake Valencia, Venezula. It has a wide range in 
Mexico and the West Indies. Professor von Martens has figured the 
shell, teeth and embryonic young. (Die Binnenmollusken Venezuelas, 
p. 208, Taf. 2, figs. 13a—-“.) 


POTAMOPYRGUS GUARANITICUS (Doering). 


Lyrodes guaranitica Doering, Boletin de la Academia Nacional de Cien- 
cias en Cordoba (Republica Argentina), VII, 1884, pp. 461-463, fig. 2. 
Length 3.5, diam. 1.9 mm., whorls 5%, the last encircled by a slender 
keel at the shoulder, and several spiral strize on the base. 
Rio Barrancas, Corrientes. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 563 


POTAMOPYRGUS SCOTTII sp. nov. 
(Plate XLIc, Figs. 10, 11.) 


The shell is very minutely perforate, turrite, the length about double 
the greatest diameter and nearly three times the length of the aperture. The 
spire has straight outlines and an obtuse apex. Whorls 6%, very convex, 
parted by a deep suture. The first two whorls are smooth; then fine, 
narrow, thread-like, spiral striae appear, 6 to 8 in number on the visible 
part of each whorl, one at the upper third sometimes being more promi- 
nent. There are also numerous ripples in an axial direction, on the last 
two whorls. The last whorl is well rounded and nearly smooth on the 
base. The aperture is ovate, peristome simple and thin, continuous, the 
columellar margin concave, narrowly reflexed. 


Fig. 10. Length 5, diam. 2.6, length of aperture 1.7 mm. 
ia Tae “6 3.8 “a axe) 66 a jig “ 


Buenos Aires. Types No. 10,153 A. N.S. P. 

This is a very much lengthened form, larger and longer than P. guara- 
niticus (Doer.), and differs in sculpture. It is closely related to P. pefen- 
ingensts (Gld.) which, however, has a smooth surface. The specimens 
are bleached and apparently fossil, being filled with sandy mud. A 
minute embryonic shell was obtained from the matrix washed out of one 
of the specimens figured. This confirms the generic reference to some 
extent, as all Pofamopyrgus species are viviparous. 

Named for Professor W. B. Scott, whose work has thrown a flood of 
light on Patagonian vertebrate palzontology. 


POTAMOPYRGUS PETENINGENSIS (Gould). 
(Plate XLIc, Fig. 12.) 


Cingula peteningensts Gould, U. S. Expl. Exped., Mollusca, p. 130, pl. 
@, fies: 152, a, 2. 

Lagoa de Peteninga, near the entrance of Rio Janeiro harbor, in brackish 
water. 

The shell of this species resembles Pa/udestrina attenuata of the eastern 
United States by its extremely convex whorls parted by deep sutures. 
The type, from the Lagoa de Peteninga, was described as smooth, about 
8.5 mm. long, 2.5 wide, with 6 whorls. One of the original lot is figured 


564 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


(fig. 12). It measures 5.4 mm. long, 2.4 wide, the aperture 1.8 mm. long, 
and is composed of 6% whorls. The apex is very obtuse. Another lot, 
received from G. von Frauenfeld, contains shells slightly more slender 
than that figured. In one of them I found two minute embryonic shells. 


IDIOPYRGUS gen. nov. 


The shell is perforate, solid, turrite, with long spire of very convex 
whorls ; aperture diagonal, oval, its plane sloping forward below, posterior 
end rounded, sinused ; a small sinus at junction of the outer lip with the 
basal margin. Lip slightly expanded, thickened within. Operculum 
paucispiral, with the nucleus at the lower fourth, near the columellar 
margin. Radula having the formula =. 7. 9. 16. 

Type, /. souleyettanus. 

The snail for which this genus is proposed differs from all known species 
of Letforzdina by its internally thickened, somewhat expanded and bisinu- 
ate peristome, the diagonal aperture, and by having fewer cusps on the 
upper reflection of the central teeth, as well ason the marginal teeth. The 
scoop-like shape of the outer marginal tooth is also rather peculiar. 


BIG: 12. 


Tdiopyrgus souleyetianus, half row of teeth and an isolated marginal tooth. 


Idiopyrgus has some resemblance to the Dalmatian genus Lanzaza 
Brusina, and to the Mexican Prerides Pilsbry. In all of them the long 
axis of the aperture stands strongly diagonal to that of the shell, the 
posterior end of the aperture is rounded, effuse or sinused, the lip ex- 
pands more or less, and the whorls of the tapering spire are strongly 
convex. These apertural characters are so unusual in 4mwzcolde, that I 
am disposed to view them as indications of real relationship between the 
three genera, rather than convergent structures in snails otherwise diverse. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 565 


Unfortunately Lanzata and Pterides are known by dead and _ bleached 
shells only, so that the relationship suggested remains hypothetical. It 
affords no safe basis for deductions concerning the antecedents of the three 
groups, each known from a single spot, and separated from its supposed 
relatives by thousands of miles. 

The genera are characterized as follows : 


Common characters:—Shell turrite, composed of very convex whorls; aperture strongly 
diagonal to the axis of the shell, oval, the posterior end rounded, spreading or sinused, 
the basal margin also retracted or effuse ; peristome continuous, more or less expanding, 
running forward below. 

a. Shell openly umbilicate, thin, sculptured with sinuous longitudinal ribs and fine spiral 
stri@, minute (2 to 3 mm. long, with 6 whorls); the aperture elliptical, lip broadly 
flaring. Dalmatia. Lanzaia Brusina. 

4. Shell rimate, thin, sooth, minute (2.5 to 3 mm. long, with 7 to 10 whorls) ; the aperture 
ovate; lip sinused or spreading above, broadly retracted or spreading at the base. 
Mexico. Pterides Pilsbry. 

c. Shell perforate, solid, smooth, of about 7%4 whorls; the aperture oval, small, the lip 
having a rounded sinus above and a smaller one at junction of outer and basal margins, 
which expand but little. Southeastern Brazil. Idiopyrgus Pilsbry. 


IDIOPYRGUS SOULEYETIANUS Sp. NOV. 
(Plate XLIc, Figs. 14, 14¢.) 


The shell is perforate, solid, turrited, greenish-yellow, opaque. The 
surface is smooth and glossy, growth-lines very faint. The spire tapers 
regularly to a small but obtuse apex. Whorls 7%, all strongly convex, 
joined by deep sutures. The aperture is oval, oblique, the dasa/ margin 
being advanced, the outer lip retracting upward. The peristome is con- 
tinuous, the outer lip expanded, somewhat thickened within. It has a 
rounded sinus just below the upper insertion, and a small sinusat the junc- 
tion of the outer and basal margins. The continuous columellar and 
parietal margins are arcuate, forming araised ledge across the parietal wall. 

Length 5.3, diam. 2.1 mm., length of aperture with peristome 1.9 mm. 

Rio Doge, State of Espirito Santo, Brazil. Types No. 100,534, A. N. 
S. Phila., from No. 127 Museu Paulista. 

In old individuals the spire becomes more or less shortened by erosion 
of the early whorls. This form differs from the Littoridinas by its peculiar 
peristome. It is probably a straggler from the fauna of eastern Brazil, of 
which little is yet known. 


566 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


POTAMOLITHUS Pilsbry 


Paludestvina in part, d’Orbigny, Voyage dans l’Amérique Meridionale, 
Mollusques, p. 381. 

Lithoglyphus sp., of some authors. 

Potamolithus Pils., Nautilus, X, Nov., 1896, p. 80. 

Amnicolidz with the shell imperforate, solid, ovate or globose, smooth 
or I-3 carinate, covered with a thick cuticle, which is usually green or 
olive; aperture ovate or rounded, the peristome continuous; columella 
concave, more or less heavily calloused. 

Operculum lodging some distance within the aperture, corneous, oval, 
reddish-brown, opaque, with-a thinner, yellowish border along the basal, 
outer and upper margins. It is composed of about 2 whorls, the nucleus 
near the lower third, and nearer the columellar side. The outer face is 
slightly concave and rather strongly striate. Inner face is glossy except 
for a long dull scar of attachment near the columellar margin (P. vzshzz). 

Penis simple, terminating in a small glans surrounded by a fleshy pre- 
putial ring. 

The radula has teeth of the form usual in Amnzcofde, central tooth 
with 2 to 4 basal cusps on each side, admedian tooth armed with 8 to Io, 
marginal teeth having many cusps, 17 to over 30. 

Type P. rush Pilsbry. 

Distribution, La Plata drainage and faunally similar streams draining 
into the Atlantic in Sao Paulo and Rio Grande do Sul, Brazil. 


Fig. 13. 


“Pen, 


Head, showing tentacles and penis, and end of the penis of Potamolithus. (After von Ihering.) 


The soft anatomy is known from A. d’Orbigny’s figures of living P. 
lapidum and H. von Thering’s description and figures of a form from near 
the mouth of the Santa Maria River, of the Rio dos Sinos drainage, identi- 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 567 


fied as P. lapfidum.! In this form “the penis is inserted nearly on the 
median line of the back of the neck (fig. 13). It was not found for a long 
time, because the number of females far exceeded the males among the 
animals examined. It is very broad at the base, provided with an obtuse 
hump and runs somewhat coiled towards the right side, where its summit 
lies near the base of the tentacle. It is perforated throughout by the vas 
deferens, and terminates in a slender conical point, which is encircled by 
a sort of prepuce.” 

Dentition of Potamolithus.—1 have examined the teeth of P. vushi 
and P. lapidum supersulcatus. The former (fig. 14) has teeth with the formula 


6, 1,6 


**6 10. 33. 40. The middle cusp of the central tooth is long but rather 


Fic. 14. 


Potamolithus rushii, A, the teeth of a half row, somewhat pressed backward, foreshortening the 
cusps, especially of the marginal teeth. B, central and cusp of the admedian teeth, in their nor- 
mal positions. 


narrow, and the side cusps are small. The cusps of the admedian tooth 
are of about equal width, but are longer in the middle, as shown in fig. 
14, B. On the inner marginal tooth the cusps are extremely small and 
numerous, and on the outer they are still more numerous. 

In P. lapidum supersulcatus from Fray Bentos on the Uruguay River 
(fig. 15) the formula is £3. 8 (4, 1, 3.) 17. 18, or in another radula, the central 


2—2 


tooth has the cusp-formula “3. All of the teeth have much larger cusps 
than in P. vashzz, and on the admedian tooth the median cusp is much 
longer than its fellows. All of the teeth have the same general shape as 


' Malakozoologische Blatter, n. F., VII, 1885, pp. 96-99. 


568 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


those of P. vushiz, the difference in the figures being chiefly due to the 
side teeth being shown in their natural positions, while in P. rashid they 
are drawn from a frayed radula, as is usually done in allied genera. 

The teeth of a form from the Santa Maria River, a tributary of the 
Sinos, identified as P. dapidum (probably not that but an allied species) 
have been figured by Dr. H. von Ihering, as having two basal teeth on 


Potamolithus lapidum supersulcatus, A, the teeth of a half-row in their normal positions. B, cen- 
tral and outer marginal teeth of another individual. 


each side. The figure is somewhat diagrammatic, but shows teeth re- 
sembling P. 2 sapersulcatus. 

The eggs are deposited in plano-convex chitinous capsules about .6 
or .7 mm. in diameter, adhering to shells and probably stones. The 
embryonic shell is smooth, Naticoid or globular in probably all of the 
species. So far as I can see, it is quite continuous with the neanic stage. 
In all of the species studied, the earlier portion of the neanic stage is also 
Naticoid. In some forms this shape persists to maturity, but in others 
angles or carinz set in, their appearance dividing the period of youth into 
two or three substages; so that a highly specialized form may pass suc- 
cessively through rounded, singly carinate, bicarinate, tricarinate, and 
finally varicose stages. The degrees to which these sculpture-conditions 
are accelerated and the stage finally reached, allow us to fix the relation- 
ships and evolutionary grade of the several forms with some degree of 
accuracy, in species where the young stages are accessible. 

These little river snails live on and under stones, at and below low- 
water mark, often in copious numbers. Up to this time, they have been 
collected at comparatively few places, yet the range of the genus probably 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 569 


embraces the whole La Plata drainage, together with some rivers flowing 
directly into the Atlantic, but having their rise adjacent to or interposed 
between the head streams of the Uruguay and Parana Rivers. Many new 
forms doubtless remain to be found, since only an inconsiderable part of 
the waters of the Plata system have been explored for mollusks. 

To what extent the specific characters of the forms vary from place to 
place, we cannot say, since most of them are known from a single locality. 
P. lapidum, which has been assigned a wide range, seems to vary with 
locality, and probably several species will eventually be recognized in 
what is now considered /apidum. Of most of the forms, many specimens 
have been studied, some of them by hundreds, and I have been astonished 
at the absence of intermediate or ambiguous individuals, such as one finds 
in the fresh-water Pleuroceratide or Melaniide. It is however well known 
to those who have studied large quantities of fresh-water snails, that the 
Ammcolide are generally conservative; the specific features are crystal- 
lized, while in the Melanians they are fluid. 


SIGNIFICANCE OF THE CHARACTERS OF POTAMOLITHUS. 


In the Amnicohde, as in the Vrviparide, the prevalent genera almost 
everywhere are smooth-shelled forms with rounded or convex whorls. 
Such forms have prevailed since the first appearance of these families. In 
those muicolide which are sculptured in the adult stage, the early 
(embryonic and early neanic) stages are smooth or nearly so. These facts 
apparently point to the conclusion that smooth, rounded shells are prim- 
itive and sculptured shells derivative in these families. 

Throughout Neocene time, carinate, varicose or otherwise strongly 
sculptured species or genera of these families have frequently appeared, 
but their distribution has been local and their duration brief. In some 
cases the genesis of these sculptured or distorted forms from smooth and 
normal types has been traced, as in the case of Vzveparus hoernesi of the 
Pliocene of southeastern Europe, and /7véfarus altior and “imnothauma of 
the Floridian Pleistocene. At the present time, sculptured /7vzfaride@ 
and Amuicoide are comparatively rare and confined to small areas. 
Margarya in Lake Tali, Zz/ofoma in the Coosa River, Pyrgulopsis in 
Pyramid Lake, Nevada, and 7vyouza in a very restricted area in the 
Southwest, are familiar examples. To these may be added the group of 
carinate species of Pofamolithus in the Uruguay River. In all of these 


570 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


cases, the distribution of the forms is very restricted, often to a single lake, 
or a few springs; and in some cases, as Pyrgulopsis and Tryonia, we 
have evidence that the species had a wider range in the Pleistocene and 
are now apparently approaching extinction. 

The facts indicate that in Amncolide and Viviparide, shell-sculpture 
is a phylogerontic character, showing the approach of senility of the race ; 
strongly developed sculpture in a species signalizes its last incarnation. 

The considerations advanced above go to show that the present Pofa- 
molithus fauna consists in large part of species which in an evolutionary 
sense are aged, are more or less distinctly gerontic or senile. Over 80 
per cent. of the species have characteristics which indicate, as experience 
has shown, that they represent side lines of evolution, impotent to continue 
the phylum, or to give birth to new phyla. There remains also a small 
group of unspecialized species represented by P. dagedum of the Parana 
and its allies in southern Brazil. 

I have been unable to find a shred of evidence to connect the develop- 
ment of sculpture in these fresh-water snails with the concentration or 
increased alkaline content of waters they inhabit, as some conchologists 
have assumed. It is doubtful whether any such modified forms inhabit 
alkaline or saline waters, while it is positively known that most of them 
do not. .4mnicofde which live in brackish or sea water are not strongly 
sculptured, but as smooth as their congeners in fresh water. Examples 
of this are found in certain species of Paludestrina (P. minuta (Tott.), P. 
acuta (Drap.), P. salsa Pils.) and LiHoridina (L. australis (d’Orb.), etc.). 
It is extremely likely that these are forms of fresh-water origin, which have 
become adapted secondarily to more or less saline waters. Part of them 
live also in perfectly fresh water. 


INTERRELATIONS OF THE SPECIES OF POTAMOLITHUS. 


The species now known belong to four collateral phyla, each compris- 
ing forms in several very diverse stages of specialization. The less dif- 
ferentiated species in each phylum retain in adults a globular or Naticoid 
shell without keels or angles, and in three of the groups have the lip 
simple and unspecialized. This type of shell is common to other genera of 
the subfamily. In all of the phyla some species have developed ortho- 
genetically a varix or crest at the lip; the shape of the shell is profoundly 
altered by spiral keels in some species. These modifications are more or 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 571 


less exactly parallel in the several series. I have attempted to express 
the above ideas graphically in the following diagram, in which the least 
evolved species of each group are placed below, while the carinate forms 
are placed above in each group. 


Outer lip not varicose. Lip varicose. 
rushii 
philippianus 

| 
iheringi 
jacuhyensis conicus 
intracallosus Buse his ee Se  orbienyi 
ribeirensis agapetus—chloris 
carinifer microthauma 
| 
quadratus tricostatus hidalgoi 
paysanduanus Supers Uicdt0s = pecstomarts 
? hatcheri 
ee apidum ee — Fdinochilus 
filipponei 
| 
| 
bisinuatyss = sae ee sykesi 
gracilis 
simplex 


[In these diagrams the most primitive, Naticoid species of each group are below ; those modi- 
fied by the development of carinz above; and the right-hand column contains derivative species 
having the outer lip varicose. The connecting lines indicate the chief affinities of the forms. ] 


While the above diagrams are not intended for phylogenetic trees, all 
the species being contemporaneous, yet it is likely that the ancestral forms 
in groups II, III and IV did not differ materially from the least differ- 
entiated of the recent species. It is significant that the only form known 
to have a wide distribution, P. dapzdum, is one of the least specialized of 
the genus. 

The evolution of carinze and varices in the several groups seems to have 
been homoplastic. It will be shown below that the keels are superposed 


572 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


upon the Naticoid form much earlier in some species than in others ; and 
judging from these various degrees of acceleration, it would seem that the 
specialized species are of unequal antiquity. 


KEY TO SPECIES AND SUBSPECIES OF POTAMOLITHUS. 


I. Columella wide, having a longitudinal furrow excavated in its face. Latter part of the suture 
not more rapidly descending ; outer lip strengthened by a strong varix. 


Da) 
a. Last whorl dominated by a very strong peripheral keel. P. rushit. 
a’. Last whorl flattened peripherally, without carina. P. philippianus. 
a’, Last whorl rounded, conspicuously banded with green. P. theringi. 


II. No longitudinal groove in the face of the columella. 
a. Outer lip well expanded or with a prominent varix ; not notched or sinuous. 
6, Periphery strongly keeled, the keel visible on part of the penultimate whorl. 
c. Three keels on the last whorl. P. microthauma., 
c’. Last whorl flattened above and below the peripheral keel. P. hidalgoz. 
c*, Last whorl globose, convex above and below the peripheral keel. 
P. peristomatus. 
é. Periphery obtuse or rounded. 


c. Lip-varix very strong ; periphery hardly angular, base convex ; back with a 


spiral rib below the suture; no columellar area. P. dinochilus. 
c’. Lip-varix narrow ; last whorl without keels, except that around the columellar 
area, L. orbignyt. 


a’. Outer lip simple or slightly contracted, without an external varix, the edge not sinuous. 
6, Last whorl sculptured with spiral keels or angles. 
c. With a single keel or angle at the basal periphery, none above it. 
d. High-trochiform, flattened above and below the strong carina, much higher 
than wide ; columella narrow. P. conicus. 
da‘. Obliquely trochiform, convex above the peripheral angle, about as wide as 
high; columella wide. P. buschit. 
c'. Trochiform, with a carina at the basal periphery and two contiguous keels on 
the back above. P. tricostatus. 
c*, Trochiform, with a strong carina at the median periphery, the slope above it 
flat, with a small carina at the upper third; no distinct umbilical area. 
IZ, carinifer. 
c*. Stout keels at both periphery and shoulder, giving the last whorl a squarish 


contour ; umbilical area ample ; spire very short. P. quadratus. 
c‘, Base and periphery rounded, a shallow sulcus or two low ridges on the back 
above. P. lapidum supersulcatus. 
c’. Back of last whorl with two contiguous angles, the upper one stronger, base 
rounded, spire rather slender and high. P. hatcheri. 


6'. Last whorl rounded, without keels, angles or sulci. 
c. Shape approaching globular, the spire short or very short, conic. 
d. Columella narrow ; last whorl evenly rounded. 
e. Green or olivaceous; alt. 5, diam. 4 mm. P. lapidum. 
e'. Yellow, alt. 3.3, diam. 3 mm. P, paranensts. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 573 


e?, Three-banded with reddish ; alt. 4, diam. 3mm. Parana River. 
P. petitianus. 
d@'. Columella and especially the parietal wall thick, forming a blackish ledge ; 
spire very short. 
e. Last whorl swollen below the suture ; olivaceous, about 5 x 4 mm. 
P. paysanduanus. 
e’. Last whorl evenly rounded; olive with black markings, alt. and 
diam. 7 mm. P. doeringi. 
d’. Columella wide, flat and white; last whorl evenly rounded. 
é. Pale green, diameter nearly equal to the alt., 3 x 2.8 mm. 2. agapetus. 


e'. Pale green, higher than wide, alt. 3, diam. 2.5 mm. P. chloris. 
e*. Olivaceous, perforate, alt. 5.7, diam. 4.3 mm. P. catharine. 
é*. Reddish brown, alt. 3.5, diam. 3.4 mm. P. ribeirensis. 


e*. Naticoid, but with an obtuse prominence on the columella far within. 


P. intracallosus. 
d*. Last whorl noticeably flattened peripherally ; solid, brown, becoming 


green at the base and behind the lip; 6 x 5.6 mm. P. jacuhyensis. 
c*. Acutely long-ovate in shape, smooth, the ovate aperture not much exceeding 
half the total length; 4.3 x 3 mm. P. simplex. 


a’, Outer lip sinuous, nicked or notched. 
6. Trochiform, the periphery very strongly carinate, aperture squarish, umbilical area 


large. P. filipponet. 
6’. Shell nearly globular, the diameter about equal to the alt., smooth, swollen below 
the suture, lip with a sinus above. P. paysanduanus sinulabris. 


8, Shell globose-conic. 
c. Outer lip strongly expanded, with swollen, thickened and three-notched face. 


P. sykesi. 
c'. The outer lip thin, with deep subsutural and basal sinuses ; 4.8 xX 3.3 to 
5 X 3-9 mm. P. bisinuatus. 


c. Similar, but with the sinuses shallower, the upper one often inconspicuous. 
P. bisinuatus obsoletus. 
6°. Shell acutely ovate-conic, about 4.3 x 2.7 mm., the outer lip thin, sinuated, especially 
at the base. P. gracilis. 


Group OF P. BISINUATUS. 
Smooth, globose-conic or ovate-conic species, with no trace of spiral 


angles or sulci, except in P. fiipfone7 ,; the outer lip usually sinuous. The 
spire is longer than in other groups of the genus. 


POTAMOLITHUS FILIPPONEI von Ihering. 
(Plate XLIa, Figs. 8, 82.) 
Potamotithus filipponei von thering, Nautilus, XXIV, June, 1910, p. 15. 
The shell is imperforate, pyramidal, olive colored, with a weak reddish- 
brown spiral band in the middle of the penultimate whorl. Surface 


574 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


smoothish, weakly marked with lines of growth. Whorls 5, the first very 
minute and dark, following whorls strongly convex, the last whorl strongly 
carinate, concave above and below the carina, convex on the upper sur- 
face. The base is excavated or concave between the peripheral keel and 
a second prominent keel which bounds a large, funnel-shaped umbilical 
area. The aperture is very oblique. Peristome continuous, the outer lip 
thin, unexpanded, having small rounded sinuses below the suture, below 
the peripheral angle, and at the base of the columella. The columella is 
narrow, very little thickened, straight, much longer than the short, thick 
parietal margin. 

Length 4.4, diam. 4 mm. 

Montevideo, Uruguay, type in the Museu Paulista, collected by Dr. 
Florentino Filippone. 

This species has some resemblance to P. /zdalgoz, from which it differs 
by the entirely different shape of the aperture, the swelling between keel 
and suture, etc. The bisinuate outer lip, the texture and color-pattern of 
the shell, etc., show it to be a carinate member of the group of P. dzsenu- 
atus. Described and figured from the type specimen. 


POTAMOLITHUS SYKESI Pilsbry. 
(Plate XLI, Figs. 1-22.) 


Potamolithus sykest Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is imperforate, globose-conic, rather solid, yellowish olive, 
smooth and glossy, faintly marked with growth lines. The spire is conic, 
truncate at the summit in adult shells of the type lot, about 3% moder- 
ately convex whorls remaining. The last whorl is evenly convex, smooth, 
and expands strongly at the lip. There is a narrow umbilical crescent. 
The aperture is very oblique and subcircular. The outer lip is strongly 
expanded, built forward and convex beyond the expansion, and then 
contracted, with three deep notches in its margin, one near the upper 
insertion, another median, the third wider and basal in position. The 
columella and parietal wall are moderately calloused, and the whole 
peristome is dusky or blackish. 


Length 4.9, diam. 3.9 mm. 
“é 4 oe 3.5 oe 
Uruguay River at Paysandu. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 575 


Development.—The neanic stage in this species is like that of P. 
bistnuatus. The ephebic stage is described above. A single gerontic 
individual before me has built the median region of the outer lip forward, 
obliterating the median notch of the lip (Pl. XLI, figs. 2, 2a). 

This remarkable form is the most advanced of the d/s¢xwatus phylum 
known. It resembles P. d¢s¢xuatus in contour, and neanic shells of the 
two species are distinguishable only by the bands of the latter, when these 
are developed. The ephebic stage differs widely by the strong expansion 
of the outer lip, its thickened and thrice notched face. 

What relation P. d¢stnuatus and P. sykes¢ bear towards P. petitianus 
(d’Orb.) of the Parana River is unknown, pending the discovery of the adult 
stage of the latter, the specimen described and figured by d’Orbigny being 
supposed to be immature. It is likely that Ae“tanus will prove to be 
different from either of the other species. 


POTAMOLITHUS PETITIANUs (d’Orbigny). 
Paludestvina petitiana d’Orb., Voyage dans |’Amérique Méridionale, Mol- 
lusques, p. 487, pl. 75, f. 19-21 (1839). 

Shell short, ovate-inflated, thin, smooth, not umbilicate ; spire short, 
eroded, with obtuse summit, composed of five convex, narrow whorls, 
parted by a suture which is not very deep. Aperture oval with simple 
margins. Color green, with three reddish bands, one on the convexity of 
the spire, the others at the suture and anterior. Alt. 4, diam. 3 mm. 
(a Orbigny). 

Parana River at San Pedro, Argentina, collector unknown. 

This may be the neanic stage of a species allied to P. d¢senuatus ; but 
in this group of forms (d¢s¢zzatus and sykes7?) the neanic stage shows no 
specific differentiation, the specific characters appearing only in the final 
stage of development. Until the adult form of P. Aetétianus is collected 
at the type locality, San Pedro on the Parana, no good purpose will be 
served by uniting either of the other species to Aefe/zanus as its hypotheti- 
cal adult. There remains also the possibility that P. efteanus is a per- 
manently undeveloped form, not passing beyond the neanic stage of the 
bisinuate species, and therefore falling more properly in the /apedum 
group. Compare also P. faranensis, p. 589. 


576 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


POTAMOLITHUS BISINUATUS Pilsbry. 
(Plate XLI, Figs. 6-72.) 


Potamolithus bistnuatus Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is imperforate, globose-conic, moderately solid, green or pale 
yellowish-green, sometimes one-colored, but usually begirt with three nar- 
row reddish-brown bands, one bordering the suture, another above the 
periphery, and on the penultimate whorl visible above the suture, and the 
third band below the periphery. The nearly smooth surface is weakly 
marked with lines of growth. The spire is conic and rather high, trun- 
cated at the summit in all adult shells seen, by the erosion of the early 
whorls, about 3% remaining. These are strongly convex, the last one 
globose, without keels or angles of any kind, and with no expansion or 
varix behind the outer lip. There is a distinct and concave but quite 
small columellar area. The aperture is moderately oblique, round-ovate, 
white or brownish inside. Its posterior angle is more or less filled with 
a callous deposit. The peristome is edged with a black line. The thin 
outer lip has a deep rounded sinus near its posterior insertion, and there 
is a second sinus, wider and not so deep, at the base, the lip projecting 
as a broad truncated lobe between the two embayments. The columella 
is concave, narrowly calloused and the parietal callus is rather thick. 


Length 5, diam. 3.9, length of aperture 2.8 mm. 
a3 4.8 66 23 66 ‘6 2.9 6c 


Uruguay Riverat Paysandu. Types collected by Dr. W. H. Rush, U.S.N., 
May 7, 1892. 

Development.—The shell is of the ordinary simple Naticoid shape 
throughout the neanic stage, differing from P. dapzdum only in having a 
longer spire. The peculiar Pleurotomoid sinuosities of the peristome 
have their origin and development wholly in the ephebic stage. In this 
respect, P. d¢stnuatus is like Pachychetlus dali Pils., and differs widely 
from Gyvotoma and Pleurotoma, in which the anal notch appears very early. 

This species is related to P. sykesz, from which, however, it differs totally 
in characters of the ephebic stage. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. B77. 


POTAMOLITHUS BISINUATUS OBSOLETUS Pilsbry. 
(Plate XLI, Figs. 3-5.) 


Potamolithus bisinuatus obsoletus Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is more slender than P. d¢s¢xuatus, acutely ovate-conic, green, 
without color bands. The outer and basal margins of the peristome have 
only shallow sinuses in place of the deep onesof P. dzsznuatus ; the upper 
one is often hardly perceptible, and, when developed, is nearer the upper 
insertion of the lip than in desezwatus. The inner margin of the peristome 
is less heavily calloused, and the columellar area is excessively narrow, 
hardly noticeable. The apices are perfect in the type lot, the shell con- 
sisting of 5% whorls. 


Length 4.9, diam. 3.5 mm.; aperture 2.8 mm. long. 
“s 4.6 “ 2. I “ 
Rio de La Plata, at San Gabriel’s Island, near Colonia, Uruguay. Also 
Uruguay River, at Fray Bentos, Uruguay. 
A large series from the first locality shows this form to be constantly 
unlike P. d¢s¢nvuatus. Ithas the characters of an immature stage of the latter. 


POTAMOLITHUS GRACILIS Pilsbry. 
(Plate XLI, Figs. 8, 82.) 


Potamolithus gracilis Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is imperforate, acutely ovate-conic, solid but not thick, olive- 
yellow, becoming reddish-brown on the spire, or dull green; smooth 
and glossy. The spire is straightly conic, rather acute. Whorls 5%, 
moderately convex, the last symmetrically rounded. The aperture is 
ovate, subvertical. The outer lip is not expanded, acute, the edge sinuous, 
being retracted slightly at the suture, a trifle sinuated in the middle, and 
having a distinct rounded sinus at the base. The columella is concave and 
narrow, the parietal callus thin. There is no differentiated umbilical area. 

Length 4.3, diam. 2.7, length of aperture 2.25 mm. 

Uruguay River at Paysandt. Types collected by W. H. Rush, U.S.N., 
July 18, 1892. 

This species is related to P. dzseneatus, but it is unlike that species in its 
narrower contour. A long series has been examined. The green speci- 
mens predominate. 


578 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


POTAMOLITHUS GRACILIS virrpIs Pilsbry. 
(Plate XLI, Figs. 9, ga.) 


Potamolithus gracilis viridis Pilsbry, Nautilus, X, p. 89, Dec., 1896. 
This form is similar to gvacz/és in contour, etc., but there is a deeper 
sinus near the upper termination of the lip, and the basal sinus is well 
developed. The color is green. The dark maculz shown in the figure 
are due to the dried soft parts. 
Rio de La Plata, at San Gabriel’s Island, near Colonia, Uruguay. 


POTAMOLITHUS SIMPLEX Sp. NOV. 
(Plate XXXIX, Figs. 6, 6a.) 


The shell is acutely ovate-conic, thin, but rather solid, pale greenish- 
yellow ; the surface glossy, faintly marked with growth-lines. The spire 
is straightly conic, apex rather acute. Whorls 5%, convex, the last evenly 
globose, not expanded at the lip. There is a distinct and rather wide flat 
axial area, bounded by a delicate keel. The suture is deep and descends 
briefly and rather abruptly close to the aperture. The aperture is oblique 
and acutely ovate. Peristome simple, thin, black-edged and continuous, 
its edge even, not in the least sinuous or notched. The columella is very 
narrow and concave. 

Length 4.3, diam. 3, length of aperture 2.25 mm. 

Uruguay River at Paysandu. 

The slender ovate contour and smooth surface ally this species to P. 
gracilis, but the total absence of any sinus or notch in the lip, the anterior 
descent of the suture and the well developed axial or umbilical area are 
features unlike P. gracilis. No young individuals have been identified, 
but they probably could not be distinguished from P. gracilis. P. simplex 
approaches Li/foridina in contour, but the anteriorly descending suture 
and the axial crescentic area are unlike that genus. 


Group OF P. BUSCHII. 
POTAMOLITHUS AGAPETUS sp. nov. 
(Plate XL, Figs. 10, 102.) 


The shell is imperforate, globular-conic, of a rather light green color. 
The surface is smoothish, faintly marked with growth-lines. Spire short 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 579 


and conic, the apex obtuse. Whorls 4, convex, the last evenly rounded, 
without keels or angles, the suture shortly deflexed at the aperture. There 
is a moderate or narrow and usually rather conspicuous columellar area. 
The aperture is oblique, rather broadly ovate. The peristome is thick- 
ened within, the basal and outer margins are evenly and strongly arcuate, 
the outer becoming straightened near the upper angle of the aperture. 
The inner lip is heavily calloused; columella rather wide and flattened. 

Length 3, diam. 2.8 mm. 

Rio de La Plata, at San Gabriel’s Island, near Colonia, province of 
Colonia, Uruguay. Types, 69,683, A. N. S. P. 

Development.— The young of about three whorls and 2 mm. diameter 
are essentially similar to the adult stage in shape. The columella is 
somewhat wider in proportion. 

This is the smallest Pofamolithus now known. It has the globular shape 
of P. dapidum, but the wide columella of the neanic stage shows that P. 
agapetus is related to P. buschit. It differs from P. buschit by the evenly 
rounded shape of the last whorl, the diminutive size and clear green color, 
as well as by the total absence of a peripheral angle or keel; but the 
young stages of P. duschii are not always readily distinguishable from im- 
mature P. agapetus. 

In some shells the aperture is smaller than in that figured, by reason 
of a greater descent of the last whorl immediately behind the lp:. The 
columellar crescent varies from quite narrow, almost linear, to quite wide 

and concave. 


POTAMOLITHUS CHLORIS sp. nov. 
(Plate XLI4, Figs.8) $0.) 


The shell is imperforate, rather solid, ovate conic, light green, the spire 
paler, summit corneous. The spire is straightly conic, apex minute, 
slightly obtuse. Whorls 4%, convex, the last evenly rounded through- 
out, expanding near the aperture. The aperture is very oblique, shortly 
oval. The peristome is slightly expanded, obtuse. Columella and 
parietal wall heavily calloused, the former flattened, rather wide. 

Length 3, diam. 2.5 mm., length of aperture 1.8 mm. 

Salto das Cruzes, Rio Tiete, State of Sao Paulo, Brazil. Type, No. 
103,046, A. N.S. P. from No. 106 Museu Paulista. Collected by Hase- 
mann, 1908. 


580 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


This snail has the texture, color and size of P. agafetus, from which it 
differs by the longer, Ammnzco/a-like shape and the small aperture. There 
is no differentiated umbilical area. 


POTAMOLITHUS BUSCHII (Ffld.). 
(Plates XL, Figs, 11-14; XLI, Fig. 3.) 


Lithoglyphus buschii Dunker, Frauenfeld, Zoologische Miscellen, V, in 
Verhandlungen der k. k. zoologisch-botanischen Gesellschaft in 
Wien, 1865, XV, p. 530, Taf. 11, first two figures. 

The shell is obliquely trochiform, being flattened below, semiglobose 
above; moderately solid; green or olive-green with irregular buff flecks 
or zigzag streaks, and usually a dusky-brown band midway between the 
periphery and suture. Surface with faint growth-lines and indistinct spiral 
stria. Spire very short, the apex usually reddish. Whorls 4%, convex, 
the first one or two usually eroded in adult shells. The last whorl is 
carinate, strongly angular, or with a rounded angle at the basal periphery, 
very convex above the keel, and usually having a low ridge on the back 
a short distance below the suture; there is also, sometimes, a second 
obtuse ridge below the upper one (fig. 13), much as in P. daprdum super- 
sulcatus. Base flattened, but slightly convex. There is a well developed 
concave columellar area bounded by an acute ridge. The aperture is 
very oblique, ovate, the outer lip without a varix, but built downward 
somewhat near and at the upper angle, contracting the aperture. The 
columellar and parietal margins are heavily calloused; columella rather 
wide, concave and flattened. 


Length 4.7, diam. 4.6 mm. 
ae ALS ia 4 66 


Mouth of the Arroyo San Juan, where it empties into the La Plata, 
Province of Colonia, Uruguay (type locality); San Gabriel’s Island in the 
La Plata, near Colonia, in the same Province, and Fray Bentos on the 
Uruguay River (Wm. H. Rush). 

Development. — At the end of the second whorl the periphery begins to 
be weakly angular, the shell being about 2 mm. in diameter. Before that 
stage the shape is globose-depressed, with a rounded periphery. At the 
end of the third whorl the angle is strong. The columella is very broad, 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 581 


its face concave, throughout the neanic stage. Figs. 11, 11a@ represent a 
young shell 3.3 mm. in diameter. 

P. buschit is related to P. agafetus, but it attains a larger size, and dif- 
fers in the coloration and angular periphery; yet there are some imma- 
ture specimens in the lot from San Gabriel’s Island, which approach very 
near to P. agafetus. It differs from P. dapedum and P. tricostatus by its 
wide columella at all stages of growth. It is a very abundant snail at 
San Gabriel’s Island, on the northern shore of the Rio de La Plata. 

The figures on Plate XL represent the least angular forms of the 
species from San Gabriel’s Island. The type was a carinate shell, such 
as that represented in Plate XLI4, fig. 3, from Fray Bentos, on the Uru- 
guay River. The ridge below the suture on the back is usually incon- 
spicuous. Most of the specimens from San Gabriel’s Island are similar 
to those figured on Plate XL, or somewhat more angular, but less so than 
shells from the mainland. They also have the ridges or sulcus on the 
back more strongly developed in some examples. 


POTAMOLITHUS CONICUS (Brot). 
(Plate XL, Figs. 8, 9, 9a.) 


Lithoglyphus conicus Brot, Journal de Conchyliologie, XV, 1867, p. 69, 
pl. 1, fig. 5 (Uruguay River in the Province of Entrerios). 

The shell is high-trochiform, rather straightly conic, solid, green or 
brownish-olive, variegated with pale green or yellow zigzag streaks. The 
smoothish surface is rather glossy, with the usual fine growth-lines. The 
conic spire is longer than in related species, and often eroded at the apex. 
Whorls nearly 4%, convex. The last whorl slopes steeply and with little 
convexity to the carinate periphery, which is basal in position. On the 
back there is sometimes a very weak ridge below the suture and parallel 
to it, but this is usually wanting. The base is flat, and there is a rather 
wide crescentic, concave columellar area defined by a sharp angle. There 
is no varix at the lip. The aperture is very oblique, symmetrically ovate, 
in fully adult shells is contracted somewhat, being filled in above; with 
a continuous, black-edged peristome. The columella is concave and 
narrow. 

Length 4.7, diam. 3.7 mm. 


‘e 3-9 e 3.3 “e 


582 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Uruguay River at Paysandt, Uruguay, under stones at extreme low 
water. 

Development.—The youngest shells at hand lack about one whorl of 
completion. At this stage the shape is practically that of adults, except 
that there is no columellar crescent and the columella is wide and flat. 
The weak subsutural ridge, when developed at all, appears on the back 
of the last whorl only. The most fully developed shells therefore have 
the characters of the four-whorled stage in P. tvecostatus, while most 
shells, wanting the upper keel, are like ¢vzcostatus at the three-whorled 
stage. 

P. conicus differs from P. tricostatus by its smaller size, more highly 
conic shape, and the less developed sculpture of the last whorl. It is 
more closely related to P. duschz, both having the columella wide during 
the neanic stage ; but in the adult stage P. duschit is depressed and P. 
conicus elevated in shape. 

The color inlifeis probably always more or less green. The rich brown 
tint of those figured may be due to change in alcohol, though I am not 
sure that this is the case, as the shells were dry when they came into my 
possession. <A lot of P. duschz which had been in alcohol have changed 
to brown, while all of those dried fresh are green. 


POTAMOLITHUS ORBIGNYI Pilsbry. 
(Plate XL, Figs. 1-5.) 


Potamolithus orbignyt Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is imperforate, globose, solid and strong. Uniform olive 
colored, or with brown bands below the suture and in the middle of the 
last whorl, on an olive or green ground. Surface smoothish, with faint 
growth-lines and fine, very indistinct spiral stria. The spire is very short 
and conic. Whorls nearly 4%, strongly convex, the later third of the last 
whorl descending more rapidly. The last whorl is squarish, obtusely 
biangular, being shouldered above, flattened in the middle, and more or 
less angular at the basal periphery. The ample crescentic columellar area 
is concave and bounded by anangle. The lip is strengthened by a narrow 
varix, which is blackish and bevelled to the lip-edge. The aperture is 
very oblique, and rounded-ovate. The outer lip is thickened within, the 
inner lip heavily calloused. The columella is broad and flattened. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 583 


Length 5, diam. 4.8 mm. 
AS eae A 

Uruguay River, at Paysandi, Uruguay. Types, No. 69,696, A. N. S. P. 

In the typical form of the species the flattening of the last whorl is 
nearly vertical below the shoulder. In other examples (Pl. XL, figs. 2, 3) 
the flattened surface slopes steeply, and the periphery is somewhat more 
angular, though still rounded off. Young shells (Pl. XL, figs. 4, 4@) with 
3% whorls, having a diameter of 2.5 mm., have a distinct flattening above 
the periphery, though less marked than in adults. This was not seen by 
my artist, who drew the peripheral region of fig. 4 much too regularly 
rounded. Fig. 5 represents a slightly larger shell, diam. 2.8 mm., the 
basal aspect drawn to show the very broad, flat, columellar callus. In 
contour it resembles fig. 2. 

P. orbignyt is somewhat related to P. dénochilus, but differs in the 
lower varix, absence of a spiral ridge below the suture, the larger columellar 
area, broader columella, etc. It is similar to P. Axz/ippianus in shape, 
but lacks the columellar furrow of that species. 


POTAMOLITHUS JACUHYENSIS Pilsbry. 
(Plate XX XIX, Figs. 3, 3a.) 


Potamolithus gacuhyensts Pilsbry, Nautilus, XII, p. 113, Feb., 1899. 

The shell is globose, solid and strong, smoothish, with the usual slight 
growth lines and scarcely visible spirals ; covered with a strong, rich brown 
cuticle, becoming more reddish towards the apex, and dark green below 
the last turn of the suture, behind the lip, and at the base. Spire short 
and conic. Whorls 4%, those of the spire convex, the last very obtusely 
biangular, being flattened peripherally, subangular at the shoulder, flat- 
tened and sloping above it, and tapering basally. There is in some 
specimens a well-developed flattened columellar crescent, but in other 
individuals it is reduced and inconspicuous. The aperture is large and 
somewhat spreading, moderately oblique and irregularly semicircular. 
The outer lip is sharp, with a dark line at the edge, not expanded, and 
not in the slightest degree varicose or contracted. The inner lip is 
heavily calloused. 

Length 6, diam. 5.6 mm. . 

Jacuhy River, Rio Grande do Sul, Brazil. Types, 61,820, A. N.S. P., 
collected by Dr. H. von Ihering. 


584 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


No immature stages are represented in the series before me. The 
species belongs to the more primitive or youthful group, by its simplicity 
of form, the absence of varices, and the want of contraction at the mouth. 
It is not closely related to any of the La Plata drainage forms, but has 
some resemblance to P. /afidum, from which it differs by the obtusely 
biangular shape, the much larger aperture, and the heavily calloused 
columella, which allies it to species of the Uruguay system, and those 
following. 

POTAMOLITHUS INTRACALLOSUS Sp. Nov. 
(Plate XLIé, Figs. g/'94) 


The shell is imperforate, solid, globose with short, conic spire, olive- 
green, blackish in the axial region. Surface very lightly marked with 
growth lines. Whorls 4%, convex, the last strongly convex below the 
suture and at the periphery, which is below the middle, somewhat flattened 
above the periphery ; base convex; an acute keel divides off a crescentic 
umbilical area. The suture descends slightly near the aperture. The 
aperture is ample, oblique, very shortly oval. The peristome is black- 
edged, not expanded. The continuous columellar and parietal margins 
are very heavily calloused, the columella broad and flattened. In oblique 
view in the aperture, a broadly rounded prominence is seen in the middle 
of the columella. 

Length 3.7, diam. 3.5 mm., length of aperture 2.7 mm. 

Hiririea, Rio Ribeira, State of Sao Paulo, Brazil. Type, No. 103,047, 
A. N.S. P., from No. 2037 of the Museu Paulista. H. von Ihering. 

This small species of the P. duschz group is notable for its very broad 
columella, with an internal node or rounded prominence. This last 
feature differentiates it from P. r7dezvensts, which closely resembles z7¢va- 
callosus in shape. 

POTAMOLITHUS RIBEIRENSIS Sp. Nov. 


(Plate XLI4, Figs’ 6, 7.) 


The shell is imperforate, rather solid, globose, red-brown, with a faint 
olivaceous tint near the outer lip; sculpture of indistinct growth-lines 
only. Spire short, conic. Whorls 3%, convex, the last globose, most 
convex at the periphery and just below the suture, the intervening surface 
somewhat flattened in some examples, but strongly convex in others. 
The periphery is very indistinctly subangular in front, but in fully adult 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 585 


shells this is often scarcely noticeable. The base tapers and is not very con- 
vex. The suture descends very slightly in front. There is an extremely 
narrow umbilical area. The aperture is oblique and ample, angular above. 
The outer lip is thin and acute, and forms a half-circle. The columella 
is very heavily calloused, its face flat or excavated, with a longitudinal 
depression. Parietal callus heavy within, thin and adnate at the edge. 

Length 3.5, diam. 3.4 mm.; length of aperture 2.7 mm. 

Rio Ribeira, Yporanga, State of Sao Paulo, Brazil. Types collected 
by R. von Ihering, 1908. 

This form resembles P. dafidum (d'Orb.) in shape, but differs by its 
very broad columella and diminutive size. It is rather closely related to 
P. buschw, though differing by the rounded periphery, which even in im- 
mature shells shows the hardly noticeable trace of an angle. P. intyacal- 
/osus is an allied species. 

A series of eight shells from Hiririea, Rio Ribeira, State of Sao Paulo, 
collected dead, but not bleached, has been submitted by Dr. von Ihering. 
The cuticle is olive-green or clear green. The shape is about as in ribeir- 
ensts. In several shells there is a very narrow umbilical area, defined by 
a raised line. In the youngest shells, diam. 2 mm., the columella is very 
wide, as in rzbezvensis, but in the largest shells, length 5.2, diam. 4.2 
mm., it is quite noticeably narrower. In one shell of this lot (Plate 
XLIZ, fig. 4 there is a wide, lunate, concave umbilical area, defined 
by an acute black keel, the columella being wide, as in P. rideivensis. It 
measures, length 4.2, diam. 4 mm. Further material is needed to show 
the status of this form, which for the present may be considered a race of 
P. ribervensts. 

POTAMOLITHUS CATHARIN& Sp. Nov. 

The shell is perforate, acutely ovate, solid but strong, covered with an 
olive-green cuticle. The spire is conic, its lateral outlines straight, the 
apex small, but somewhat obtuse, entire in adult shells. Whorls 5%, evenly 
convex, parted by an impressed suture, which descends very briefly at the 
aperture. The last whorl is strongly convex throughout ; near the aper- 
ture it dilates a little. The aperture is slightly oblique, ovate, fleshy- 
gray within, blue-white near the lip. The outer lip is thin and black at 
the edge, and with the basal lip forms a half-circle; in profile its edge is 
_ even. The columella is heavily calloused, the callus extending across the 
parietal wall, where it is less thickened. There is a distinct umbilical 


586 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


perforation and a feebly differentiated axial or columellar area, linear in 
the adult stage, but becoming wider in old shells. 

Length 5.7, diam. 4.3, length of aperture 3.8 mm. 

Colony of Hammonia, State of Santa Catharina, Brazil. Types, No. 
103,048, A. N. S. Phila., from No. 163 of the Museu Paulista. 

This is a.much more robust species than P. scmplex. It differs from 
P. lapidum by the produced spire and heavier columella. It is unlike all 


(Fig. 16.) 


Fic. 16. Potamolithus catharine. 


described forms in having a distinct umbilical perforation. The apex is 
perfect in all of the shells received, although the oldest of them has the 
last whorl deeply eroded. 

GROUP OF P. LAPIDUM. 


POTAMOLITHUS LAPIDUM (d’Orbigny). 


Patludina lapidum @ Orbigny, Magazin de Zoologie, p. 29 (1835). 

Paludestrina lapidum WOrbigny, Voyage dans |’Amér. Mérid., Mol- 
lusques, p. 382, pl. 47, f. 4-9. 

Flydrobia lapidum Strobel, Materiali per una Malacostatica di terra e di 
acqua dolce dell’ Argentinia Meridionale, 1874, p. 59, with var. 
AunheKe, tC, 1p) 50; pleut is: 

? fTydrobia lapidum WV Orb., E. von Martens, Malakozoologische Blatter, 
XV, 1868, p. 192 (Guahyba River at Porto Alegre; near Réders- 
berg; in the forest region and Cima da Serra at the Estancia of 
Christian Horn, on the plateau, 3-4000 ft. elevation; collected by 
Dr: Hensel): 

?Lithoglyphus lapidum ad Orb., von Thering, Malakozoologische Blatter 
(neue Folge), VII, 1885, pp. 96-99, figs. 1-3 (dentition, head and 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. , 587 


penis of specimens from the Santa Maria River, near its confluence 
with the Rio dos Sinos). 

?Lithoglyphus lapidum d’Orb., Clessin, Malak. Blatter, n. F., X, Pp 170 
(Guahyba débris ; Santa Maria River). 

“Shell inflated-conic, short, thick, smooth, spire conic, acute at the 
summit; whorls 5, convex, the last whorl usually depressed, all being parted 
by a deep suture. Aperture round, ample, with thick borders, not reflexed. 
The columella is calloused. Color uniform green. Operculum corneous, 
flexible, spiral. 

“Alt. 5, diam. 4 mm. 

“This species is closely related to the preceding (P. Beristomatus) by 
its short shape; it differs constantly by wanting a carina, and by the non- 
reflexed peristome”’ (d’Orbigny). 

“P. lapidum inhabits the whole course of the Parana and La Plata, from 
well above Corrientes to Buenos Aires, or from 27° to 34°S. lat.; on 
stones, clinging in great numbers to the under side, at extreme low water. 
It moves quite actively” (d’Orbigny). 

The typical form of P. dapidum, figured by d’Orbigny, has an evenly 
rounded last whorl, though his phrase, “le dernier [tour] est souvent 
comme déprimé,” indicates that the Parana shells are frequently com- 
pressed around the upper part of the last whorl. Mr. E. R. Sykes, who 
kindly examined the types of the species for me, states that one specimen 
is so characterized. The aperture is ample, the lip not in the least con- 
tracted and not thickened, the columella only moderately thickened. 

The variety dunkeri of Strobel, from the Rio de La Plata at Olivos, near 
Buenos Aires, seems to differ from P. lapidum only by its small size ; 
length 4, diam. 3.5 mm., with 4 whorls. It was described from a single 
individual, and probably has no racial significance. 

I have not seen typical P. Zafidum from the Uruguay River. 

In the State of Sao Paulo P. dapidum has been reported by several 
authors from streams flowing into the Atlantic, as quoted in the references 
above, which I am unable to control; but I doubt whether the true 24 
lapidum is found in those waters. 

A form of P. dapfidum having the spire rather longer than d’Orbigny’s 
type figures is drawn in figs. 4, 5, 5a of Plate XXXIX. It is from the 
Uruguay River, exact locality not noted. 

At Paysandt, Uruguay a race occurs differing somewhat from typical 


588 PATAGONIAN EXPEDITIONS: ZOOLOGY. 
pe 

P. lapidum (Plate XLIZ, fig. 5). The shell is solid, globose, with conic 
spire longer than in P. /apidum, though the apex is eroded in all speci- 
mens seen. Aperture smaller than in /afzdam, somewhat contracted by 
an internal thickening and contraction of the lip above. Columella 
narrow. A very narrow umbilical area is defined by an angle, which runs 
very close to the columellar lip. This race may be called var. e/ator. 

Length 4.5, diam. 3.5 mm. 

The long spire separates this form at once from P. faysanduanus, which 
moreover differs in the shape of the last whorl. In old examples the 
aperture is more contracted than in that figured, and the spire is more worn. 


POTAMOLITHUS LAPIDUM SUPERSULCATUS Pilsbry. 
(Plates XXXIX, Figs. 7, 7a; XLIa, Fig. 7.) 


Potamolithus lapidum supersulcatus, Pilsbry, Nautilus, X, p. 88, Dec., 1896. 

The shell is like P. dafzdum in its globular shape. It is dark green, 
usually with pale, irregular zigzag markings, sometimes confined to the 
spire, and there is usually an indistinct brownish band above the pe- 
riphery. On the last whorl an obtuse ridge revolves not far below the 
suture, most prominent on the back; this is followed by a concavity, 
below which there may be a second obtuse angle. The base is quite full 
and rounded. The suture descends suddenly to the aperture, which is 
therefore a little contracted, oblique and ovate. The peristome is acute, 
dark-edged, continuous, without trace of a varix. The columella is 
narrow and concave, and the parietal wall is only moderately thickened. 
Whorls 4%. 

Length 5.3, diam. 4.7 mm. 
DAS Atel On ae 

Rio de La Plata, at San Gabriel’s Island, near Colonia, Uruguay. 
Also Uruguay River at Fray Bentos, and Paysandt, Uruguay. 

Development. — The spiral ridges appear only on the last whorl, and 
usually only on its last half. Up to that time the whorls are rounded and 
the shape Naticoid. At all stages of growth the columella is quite narrow. 

Potamolithus ¢. supersulcatus is quite closely related to P. fricostatus 
(Brot), from which it differs chiefly by the weaker spiral ridges, which are 
only one or two in number, not three, as in P. ¢vicostatus. These ridges 
are not only less emphatic in szferszlcatus, but they do not appear so 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 589 


early in the development of the individual. The narrow columella is 
similar in the two species. 

The specimens from Fray Bentos and Paysandt (where only a few were 
taken), have no second angle below the upper spiral ridge on the back. 
It is a very abundant snail at San Gabriel’s Island. Specimens preserved 
in alcohol become brown when dried ; and this is also true of most, prob- 
ably all, of the dark green species. 

The figures by von Iterson, on Plate XXXIX, represent a very dark 
green specimen. They are not so characteristic as that on Plate XLIa, 
which shows the back of an example with the color-pattern fully developed. 


POTAMOLITHUS PARANENSIS Sp. NOv. 
oO 
(Plate XLI4, Figs.’ 10, 41) 


The shell is globose, with conic spire, olive-yellowish, smooth except for 
fine growth-lines and very fine, indistinct spiral stria. Whorls strongly 
convex, the last swollen below the suture, in its latter part flattened below 
the swelling, rounded at the periphery and base. The aperture is very 
oblique, ovate, outer lip thin and sharp. Columella moderately calloused. 


Fig. 11. Alt. 3.3, diam. 3 mm.; 3 whorls remaining, the apex eroded. 
fealOn ee 2a  og “whorls, the apex perfect. 


Rio Parana at Puerto Bertoni, Paraguay, collected by A. de W. Bertoni, 
No. 103,049, A. N. S. Phila., from No. 189, coll. Museu Paulista. 

From the’sharpness of the outer lip, I am disposed to think that none 
of the specimens is fully mature, though the largest one must be nearly 
so, as it is eroded like an old shell. It differs from P. dafzdum by the 
longer spire, small size and pale color. There are two specimens in the 
collection of the Academy of Natural Sciences of Philadelphia, three in 
that of the Museu Paulista. 


POTAMOLITHUS DOERINGI Sp. NOV. 


The shell is subglobular with a short conic spire, solid and strong, 
olive-colored, more or less streaked or mottled with black. The surface 
is dull, lightly marked with fine lines of growth and extremely weak, 
coarse spirals ; 3% whorls of the spire remain, the apex being eroded in 
adult shells. The whorls are strongly convex, parted by a deep suture, 
which descends briefly at the aperture. The last whorl is convex through- 


590 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


out. Aperture quite oblique, large, white within. Peristome black, a 
little contracted, more so above, black. Columella and parietal wall 


(Fig."17.) 


Fic. 17. Potamolithus doeringt. 


moderately calloused, the edge black, continuous. There is a concave, 
crescent-shaped umbilical area defined by an angular ridge. 

Length 7, diam. 7 mm.; length of aperture with peristome 5.7 mm. 

Salto do Yguasst, Province of Missiones, Argentina, collected by Dr. 
H. von Ihering, June, 1g1o. 

This is a larger species than P. dafidum (d’Orb.), with the last whorl 
decidedly more dilated, the aperture more oblique, and a crescentic umbili- 
cal area developed. When collected, the shells were heavily coated with 
black ferrous material and most of them bear egg-capsules on the shell. 


POTAMOLITHUS PAYSANDUANUS von Ihering. 
(Plate XLIa, Figs. 1, 1a.) 


Potamolithus paysanduanus v. Thering, Nautilus, XXIV, 1gto, p. 15, with 
forms szxulabris and tmpressus. 

The shell is imperforate, solid, subglobular, olive-colored, smooth except 
for weak growth-lines, shining. The spire is very low, conic, the apical 
whorls eroded in all the individuals seen; three whorls remaining are 
strongly convex. The last whorl is swollen below the suture, then some- 
what flattened, rounded at the periphery and base. The suture descends 
abruptly to the aperture in fully adult shells. The aperture is somewhat 
oblique, ovate. The peristome is black, with obtuse, flat edge; the outer 
and basal margins are narrow; the upper part of the outer lip and the 
upper angle are wide, and the columellar and parietal margins are very 
wide and flat, black, contracting the aperture. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 591 


Length 4.8, diam. 3.9 mm. 

Paysandt, Uruguay. Dr. Florentino Filippone. Types, No. 103,070, 
es IN Sn ® 

This form differs from P. dapidum by its contracted aperture, the inner 
and upper margins of the peristome being heavily thickened within, the 
thickening covered with a blackish cuticle. In P. /afidum the aperture 
is ample, with no such heavy thickening. In the stage immediately pre- 
ceding maturity the columella has a moderate white callus within, and 
the parietal callus is quite thin. The type specimen is figured. Six 
others I have seen show no significant variation. 

With these specimens two other forms were sent which seem to be 
phases or varieties of the same species, but not intergrading in the mate- 
rial examined. Whether they occurred in the same or in separate colonies 
is not known. 

Form sInuLapris (Plate XLIa, figs. 2, 3). The shell differs from typical 
P. paysanduanus by having a low rounded ridge behind the outer lip, 
which is black, contracted, and has @ vounded sinus above. The basal lip 
is narrow and a little retracted. The columellar and parietal margins are 
not so broad as in Jaysanduanus. There is an excavated umbilical area, 
but it is generally not distinctly defined by an angle. The shape is other- 
wise as in P. faysanduanus. 


Length 4.5, diam. 4.9 mm. 
eg a eee 

Form rmpressus (Pl. XLIa, figs. 4, 4a). The shell resembles typical 
paysanduanus as far as the middle of the last whorl, after which it has an 
impressed, concave zone a short distance below the suture, and usually a 
sinus in the upper part of the lip. The outer lip is thin and sharp, with 
no external varix or swelling. The shell, under the cuticle, is light yellow. 

Length 5, diam. 4.8 mm. 

Up to the time of reaching the size of adult P. Aaysanduanus, this form 
grows normally. After that, instead of forming a contracted aperture, it 
adds a half whorl, which is distorted by a superior concave zone and finally 
terminates with a thin outer lip. The specimens were sent with typical 
paysanduanus. 


592 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


POTAMOLITHUs QUADRATUS Pilsbry & von Ihering, sp. nov. 
(Plate XLIa, Figs. 6, 6a.) 


The shell is solid, imperforate, light olivaceous-brown, lightly marked 
with growth-lines, shining. The spire is very short, 3% whorls remain- 
ing, the apex being eroded. The penultimate whorl has a strong angle 
at its upper third, is flat and horizontal above the angle, flat and sloping 
below it. The last whorl is bicarinate, the peripheral and shoulder carinz 
being about equally strong, giving it a square appearance. The base 
tapers to a rather high ridge, which bounds a wide, excavated, umbilical 
area. The peripheral angle becomes obsolete just behind the outer lip, 
and it is visible only on the last whorl. The aperture is very oblique, 
ovate, white within. Peristome a little contracted, its face flat and thick- 
ened within, at and above the periphery and in the upper angle; below 
the periphery it is thin and a little retracted. The columella and parietal 
wall are moderately calloused, a groove in the face running parallel to 
their outer margin. 

Length 3.9, diam. 4 mm. 

Paysandu, Uruguay. Dr. Fl. Filippone. 

This snail differs from P. carznzfer in the shape of the last whorl, the 
much stronger upper keel (which is developed earlier) and in having a 
large umbilical area. It lacks the median keel and variegated colora- 
tion of P. ¢vicostatus. 

A young shell 2.4 mm. diam. consists of 2% whorls, the first 1% are 
rounded; the keel at the shoulder then begins, rapidly becoming 
strong. The columella is very wide, its face excavated. 


POTAMOLITHUS CARINIFER Sp. NOv. 
(Plate XLIa, Figs. 5, 52.) 


The shell is imperforate, trochiform, solid, blackish-brown in old 
individuals, the shell of a brick-red tint below the cuticle. Surface lightly 
marked with growth-lines. The spire is very short, conoidal. Whorls 
about 4, the earlier ones convex. The first half of the penultimate whorl 
is convex; then a small carina gradually arises a short distance below 
the suture, the surface flat and sloping below it; a little later a strongly 
projecting keel appears just above the lower suture, being uncovered by 
the descent of the last whorl. The last whorl has a strongly projecting 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 593 


peripheral keel and a small keel near the suture, the surface flat between 
the keels. The base is a little convex. The umbilical area is slightly 
excavated, but not bounded by a ridge or keel. The suture descends 
slowly in its last third of a whorl, and then rapidly at the aperture. The 
aperture is very oblique, shortly ovate, flesh-tinted inside. Peristome 
blunt, not expanded. Columella concave, rather narrow, its face slightly 
grooved. Parietal wall rather heavy-calloused. 

Length 4.2, diam. 4.1 mm. 

Paysandu, Uruguay. Dr. Florentino Filippone. 

This species closely resembles P. mcrothauma, from which it differs 
by the entire absence of a varix behind the outer lip; the coloration is 
also different, but the type is probably abnormally dark, being an old shell 
which has lost part of the cuticle. 


POTAMOLITHUS TRICOSTATUS (Brot). 
(Plate XL, Figs. 6, 6a, 64, 7.) 


Lithoglyphus tricostatus Brot, Journal de Conchyl., XV, 1867, p. 68, pl. 1, 
fig. 4 (Uruguay River, Province of Entrerios). 

The shell is trochiform, solid and strong; olive-colored, profusely 
marked with irregular or zigzag buff spots. The surface is glossy when 
clean, with the usual weak growth-lines and minute spiral striz. Spire 
short, convexly conoidal. Whorls 4%, the first three convex. A ridge 
then gradually appears below the suture, increasing to a strong carina on 
the back of the last whorl. The last whorl has also a thick, strong keel 
defining the base, and a short keel, chiefly dorsal, above the middle of the 
slightly convex surface between the two keels. The base is flattened, but 
a little convex; a small columellar area is usually distinctly differentiated. 
The last whorl expands slightly at its termination, and then contracts. 
The aperture is very oblique, rounded-ovate, bluish-white within. The 
peristome is continuous, black-edged. The columella is narrow and con- 
cave; and, with the parietal wall, is moderately calloused. 


Length 5, diam. 5 mm. 
bogs wach, * 
Po TAN ee) 39% 
Uruguay River, at Paysandut, Uruguay. 
Development.—The youngest shells seen have nearly 4 whorls. The 


594 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


upper and lower keels are already strongly developed near the lip, but 
there is no trace of the intermediate keel, which in adults is less than one 
whorl long. The two keels present are very weak at the beginning of 
the fourth whorl, the basal one stronger there than the upper, so that 
apparently at 2% whorls the form must be Naticoid, like P. dapzdum. 
The next stage, at about 3 whorls, would have a basal angle only, like 
P. buschit. The columella is narrow, as in P. /apedum, throughout the 
neanic stage. The ephebic stage is marked bya slight expansion, forming 
a narrow and low varix. Fully adult shells are markedly gerontic by 
reason of the strong post-variceal contraction. 

The figures of this species given by Brot are unsatisfactory from being 
too small properly to show its characters. The median keel is shown too 
low in position. The original locality was indefinite, but comprised an 
area including the river in the neighborhood of Paysandu. Three speci- 
mens of the original lot, received from Dr. Brot, agree with those col- 
lected by Dr. Rush at Paysandu. 


POTAMOLITHUS HATCHERI Sp. Nov. 
(Plate XX XVIII, Figs. 6, 62.) 


The shell is imperforate, turbinate, solid and strong, pale yellowish- 
green, becoming darker and narrowly streaked with dark green on the later 
half of the last whorl; on the penultimate whorl the color changes to rich 
reddish-brown, becoming darker towards the summit. Surface glossy, with 
faint growth-lines and fine, indistinct spiral striz. Spire conic, high and 
rather slender, the apex lost in the type, a pit in its place. Three whorls 
remain, the first two of them evenly convex. The last fourth of the 
penultimate whorl is very obscurely biangular, the lower angle more dis- 
tinct than the other. These angles are more pronounced on the face of 
the last whorl, and on its later half the upper angle rises intoa strong keel, 
the surface above it concave; at the same time, the lower angle loses in 
prominence, and is quite lost behind the lip. An extremely weak spiral 
ridge is developed on the back below the suture. The base is rounded. 
The last third of a volution of the suture descends more rapidly. There 
is no trace of a varix atthe lip. The aperture is quite oblique, as wide as 
high, almost circular, but slightly angular above. The lip is obtuse, thick- 
ened within, with a continuous blackish marginal line. The columella is 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 595 


very concave, and not wider than the outer lip, and is bounded outside by 
a linear, hardly noticeable columellar area. 

Length 5.5, diam. 4.9 mm. 

Uruguay River, at Paysandt, Uruguay. Type, No. 90,218, A. N. S. P. 

This species is based upon a single specimen, quite adult and to all 
appearance perfectly normal, yet so unlike other known species that its rela- 
tionships are doubtful. The prominent characters of P. hafchert are the 
elevated and tapering spire and the approximation of the two angles of the 
last whorl, the upper one finally dominating, while the lower becomes obso- 
lete on the last half of the last whorl. The absence of a lip-varix and of 
a noticeable columellar area, as well as the rather narrow columella, are 
features like the P. dafidum group. The young shell, up tothe middle of 
the penultimate whorl, must be ovate, without angles ; but in the absence of 
immature specimens, not muchcan be said of the development of the species. 

It is named to honor Mr. J. B. Hatcher. 


POTAMOLITHUS DINOCHILUS Pilsbry. 
(Plate XX XVII, Figs. 5, 7, 74, 74, 8.) 


Potamolithus dinochilus Pilsbry, Nautilus, X, p. 87, Dec., 1896. 

The shell is globosely trochoidal, imperforate, very solid and _ thick ; 
green, profusely marked with irregular, zigzag buff streaks. The surface 
is smoothish, with the usual faint growth-lines and indistinct fine spiral 
stria. The spire is conic, rather high when preserved entire (fig. 8), but 
worn to a blunt summit in all adult shells seen. There are 4% whorls, 
but only 2% to 3 remain in adults. The earlier whorls are rounded, but 
at the beginning of the last a small ridge arises a short distance below the 
suture. The last whorl is somewhat flattened and slopes steeply to the 
basal periphery, which is full and narrowly rounded or subangular. The 
ridge below the suture is narrow, but well developed on the back. The 
columellar area is ill-defined and very narrow. The lip is strengthened 
by a varix, which above the periphery is very high, massive and recurved, 
but becomes weak at the base. The aperture is very oblique, contracted, 
irregularly rounded, with the margins built out beyond the varix, con- 
tinuous around the mouth, thick and obtuse. The columella is strongly 
concave, and moderately calloused, not more than the lip generally. 

Length 4.9, diam. 5.2 mm. 


“e 4.5 e 5 se 


596 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Uruguay River, at Paysandt, Uruguay. Types, No. 69,695, A. INSSHie: 

Development. —The series at hand contains no young shells, one only 
(Pl. 38, fig. 8) has not yet formed the post-variceal contraction. It ap- 
pears however that, until the last whorl is reached, the shell has the primi- 
tive Naticoid shape. The last whorl represents morphologically the 
second neanic substage of such accelerated forms as P. mzcrothauma. The 
strong post-variceal contraction and heavy thickening of the inner margin 
of the peristome declare that the last stage is distinctly gerontic. 

P. dinochilus differs conspicuously from P. mecrothauma, hidalgot and 
pevistomatus by the absence of a peripheral keel, and from P. orbignyz 
by the shape of the last whorl and the ill-developed columellar area. It 
has perhaps more in common with the P. /afzdum group, especially in the 
coloration and the persistence of the Naticoid form to the beginning of the 
last whorl; but the very high, massive lip-varix of P. dmochilus is a fea- 
ture unlike any of the /apzdum group. 


POTAMOLITHUS PERISTOMATUS (d’Orbigny). 


Paludina peristomata, a Orbigny, Magazin de Zoologie, p. 29, 1835. 
Paludestrina peristomata, VOrb., Voy. dans l Amér. Meérid., Moll., p. 382, 
pl 47,4. 1—3: 

“The shell is short, trochoidal, thick, smooth, carinate in front, the 
carina projecting. Spire conic, short, obtuse at the summit, composed of 
5 convex whorls, of which the last is keeled in front, the carina forming a 
border above the suture between the other whorls. Aperture round, much 
expanded, with thick, reflexed borders; the columella wide and _ flat. 
Operculum corneous, spiral. Color uniform greenish, paler in front of the 
mouth. 

“Alt. 5, diam. 5 mm.” (d’Orbigny). 

Pardua River, above its confluence with the Paraguay River, at the 
villages of Itaty and Iribucua, Province of Corrientes, Argentina, at extreme 
low water, under stones where the current is strong; living in numerous 
families (d’Orbigny). 

In general shape this species resembles P. dzschzz and P. conzcus, but it 
differs from both by the well-expanded peristome. It is known by the 
original lot only. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 597 


POTAMOLITHUS HIDALGor Pilsbry. 
(Plate XXXIX, Figs. 1, 1a, 14.) 


Potamolithus hidalgot Pilsbry, Nautilus, X, p- 87, Dec., 1896. 

The shell is imperforate, trochoidal, with flattened base and conic spire ; 
moderately solid. The type specimen is dull reddish-brown, somewhat 
olive-tinted at the base, and olivaceous blackish on the lip-varix ; but 
some immature shells of the original lot are dull olive-colored, darker on 
the keel. The surface is slightly marked with growth-lines. The spire is 
conic. There are 4% whorls, the first 2% convex; then a keel appears, 
immediately above and filling the suture. The last two-thirds of the last 
whorl descends slowly, the peripheral keel projecting above the suture. 
The last whorl is flat and slopes steeply above the peripheral keel, and is 
slightly convex below it. A very narrowly crescentic columellar area is 
defined by an inconspicuous, but acute angle. The outer lip is strength- 
ened by a moderately strong varix, not continued below the termination 
of the peripheral keel. The aperture is extremely oblique, rounded-ovate, 
angular above and indistinctly so outwardly, at the termination of the 
keel. The columella is arcuate and moderately calloused. 

Length 5.2, diam. 5 mm. 

Uruguay River, at Paysandu, Uruguay. Types, No. 69,687, A. N. S. P. 

A very weak ridge below and near the suture may be seen in two 
immature shells of the type-lot, but this is not developed in the others. 
The early neanic substage is Naticoid, like the corresponding age in P. 
microthauma. The rest of the neanic Stage is the equivalent of substage 
2 in P. microthauma. The deep descent of the last whorl gives a markedly 
gerontic character to the adult stage. P. 4idalgot is therefore less evolved 
sculpturally in wanting the third neanic substage, senile characteristics 
supervening earlier. 

The species is named in honor of Dr. J. G. Hidalgo of Madrid, author 
of a beautiful work on the mollusks of the Spanish Commission to South 
America, among many other important labors. 


POTAMOLITHUS MICROTHAUMA Pilsbry. 
(Plate XXXVIII, Figs. 2, 2a, 24, 3.) 
Potamolithus microthauma Pilsbry, Nautilus, X, p- 87, Dec., 1896. 
The shell is imperforate, biconic, very solid and strong. The last whorl 
is olive-green, rather profusely marked with irregular buff maculae, which 


598 PATAGONIAN .EXPEDITIONS: ZOOLOGY. 


are sometimes absent on thebase. The lip-varix is bright green. On the 
penultimate whorl the ground-color changes to purple-brown and the 
markings disappear, the earlier whorls being uniform dark purple-brown. 
The surface shows delicate growth-strize and a very minute, almost effaced 
spiral striation. The spire is conic, with straight outlines, the apex entire 
and obtuse, though small. Whorls 5, the early ones convex, the first 234 
being rounded, without trace of keels. A peripheral keel then begins, 
strong from the beginning, and projecting flange-like above the suture. 
The last whorl descends slowly from about its last third and much more 
rapidly near the aperture. The peripheral keel projects very strongly and 
is slightly undulating ; and a small keel arises below the suture, becomes 
stronger on the back, then gradually decreases. On the base, midway 
between the periphery and center, a low keel revolves, the area within it 
being nearly flat. There is a very narrow crescentic columellar area. 
The outer lip is strengthened by a very high and massive varix, which is 
recurved above, with a rib on its face running to the lip-edge, and below 
passes into the basal keel. The aperture is very oblique, ovate ; the outer 
lip thin at the edge. The columella is narrowly calloused and regularly 
concave. 
Length 5.5, diam. 6 mm. 


a9 4.6 a AT, a 


Uruguay River, at Paysandt, Uruguay, under stones at low water, 
types No) 60,680, 205IN: os P: 

Development. — The neanic stage is sharply divided into 

(1) A Zapidum substage, in which the shell is rounded, without keels. 
comprising the first 234 whorls. 

(2) Acarinate substage, initiated by the almost abrupt rise of the periph- 
eral carina. From a half whorl to a whorl this is the only keel developed. 
This stage corresponds to the adult P. Zzda/goz, and is of brief duration. 

(3) The basal and the subsutural carinze begin, weak at first, becoming 
stronger near the end of the substage. 

The ephebic stage is announced by the expansion to form the varix, 
which, however, is not terminal, the whorl continuing and contracting 
beyond it, thus assuming gerontic characteristics. 

P. microthauma is related to P. hidalgot and P. peristomatius, but it is 
a much more evolved form than either, structures added in the second 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 599 


and third neanic substages of mécrothauma being superposed upon the 
adult structure of P. hédalgo7. 


Group OF P. IHERINGI. 
POTAMOLITHUS RUSHII Pilsbry. 
(Plate XXXVIII, Figs. 1, ra, 14, 4.) 


Potamolithus vushit Pilsbry, Nautilus, X, p. 89, Dec., 1896. 

The shell is imperforate, wider than high, biconvex, very solid and 
strong ; light green, the last half of the last whorl dusky green, the keels 
rather bright green; the early whorls being dark reddish-brown. The 
surface is somewhat glossy, with faint, fine growth-lines and barely per- 
ceptible spiral lines. The spire is convex, the apex obtuse. Whorls 4, 
but the first is eroded, leaving a pit, in all the adult shells seen. The 
whorls are convex, with seam-like sutures. In the latter part of the pe- 
nultimate whorl the peripheral keel is usually visible at the suture. The 
last whorl has a very strong peripheral keel, the surface being concave 
above and below it. Above the concavity the upper surface is convex, 
the convexity rising into a hump on the back, then disappearing, the last 
fourth of the whorl being flat. The base haS a thick and prominent keel, 
defining a concave yellowish columellar area. The outer lip has a high, 
narrow varix at the edge. The aperture is very oblique, short-ovate, 
nearly circular, with a continuous, black-edged margin. The oblique 
columella is very broad, with a gutter or concavity near to and parallel 
with the inner margin. 

Length 4.3, diam. 6.3 mm. 


“c 5.1 “ 6.3 “ 


Uruguay River, at Paysandi, Uruguay. Types, No. 69,686, A. N. S. P. 

Development.—The youngest specimens seen have three whorls and a 
diameter of 3 mm. They have the depressed contour of adults and are 
strongly carinate peripherally, but the carina is distinctly weaker in front 
of the mouth, apparently indicating that it begins when the shell has 
nearly two whorls and a diameter of about a millimeter. At the 3 mm. 
stage the columella is very broad, semicircular, with a deep excavation and 
rod-like inner border (Pl. XXXVII, fig. 4). Very late in the neanic stage 
the basal keel appears, the shell then being about 5 mm. in diameter : the 
columellar area being very narrow, at first linear. The rib or convexity 


600 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


of the upper surface is also of late appearance, these structures belonging 
to the third neanic substage, the second, or unicarinate, substage thus 
occupying the greater part of the neanic stage. The discontinuation of 
the upper ridge or hump initiates the ephebic substage. The marginal 
varix and the absence of any tendency of the last whorl to descend or 
loosen its coil anteriorly, show that this species is at its acme. It has 
none of the stigmata of senility which are so manifest in P. mzcro- 
thauma, P. hidalgoz, etc. 

There is some variation in the degree of depression of the whole shell, 
the amplitude of the columellar area and in the prominence of the hump 
on the back, which is sometimes almost suppressed. The size also varies, 
one specimen before me with the varix nearly complete measuring only 
5 mm. in diameter. 

The relationship between P. vushi and P. theringt is exceedingly 
interesting. The two species are similar in general color-scheme, in the 
varix, absence of more rapid descent of the suture towards the mouth, 
etc., but are totally diverse in contour, the one being carinate, the other 
smooth and Naticoid. Yet it is significant that while P. zeringz has no 
trace of a peripheral keel, the green band occupies the same position as 
that coloring the keel in P. vashi7. 


POTAMOLITHUS IHERINGI Pilsbry. 
(Plate XX XIX, Figs. 2, 22.) 


Potamolithus theringt Pilsbry, Nautilus, X, p. 87, Dec., 1896. 

The imperforate or rimate shell is globular-conic, very solid and strong, 
pale olive-yellow, with a sharply defined, bright green band bordering the 
suture below and another immediately above the periphery, visible as a 
narrow border on the penultimate whorl above the suture; the columellar 
area being also dull green. Very faint growth-lines and an almost effaced 
spiral striation are visible under the lens. The spire is low conoidal, the 
suture clearly incised but not impressed. Whorls 4%, the first half whorl 
usually lost in adult shells; the rest are slightly convex, the last whorl 
being globular, at first regularly rounded, but its last third descends slowly, 
and is perceptibly flattened obliquely in the peripheral region, being more 
full and convex below. The base is convex, but there is a concave cres- 
centic columellar area defined by an inconspicuous angle. The outer lip 
is strengthened by a moderately strong varix, bevelled to the lip-edge, 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 601 


and weak at the base. The aperture is quite oblique, ovate, subangular 
above. The outer lip is thick within. The columellar margin is some- 
what straightened, the columella very wide, flattened and excavated, a 
rather deep furrow running parallel with and near to the inner edge. 


Length 5, diam. 4.9 mm. 
“49 “4.6% 

Uruguay River, at Paysandt, Uruguay. Types, No. 69,698, A. N.S. P. 

Development.—The youngest individuals seen have 3% whorls, with a 
length of 2.3 and diam. of 2.8mm. They are therefore more depressed 
than the adult stage, and have both green bands well developed. The 
subsutural green band begins at the end of the second or beginning of 
the third whorl. The axis is wholly imperforate. The columella is very 
broad, half-round, with the excavation in its face deeper than in adults. 
At no stage are there any traces of carinz or protuberances. 

I have seen a long series of this species. The characters described 
above are very uniform, and it is readily known by the Naticoid shape, 
grooved columella and green bands. Named in honor of Dr. H. von 
Ihering. 

POTAMOLITHUS PHILIPPIANUS Sp. Nov. 
(Plate XLI4, Figs. 1, 1a, 2.) 


The shell is globose, solid and strong, light greenish yellow, with a 
narrow dark green border below the suture, the apex pinkish. The surface 
is nearly smooth, showing faint growth-lines and fine, very indistinct 
spiral stria. Spire low, conic, the apex minute, entire. Whorls 4%, 
convex, the last not more rapidly descending, distinctly flattened periph- 
erally, shouldered above the flattened zone, very obtusely subangular 
below it, the base convex, with a rather wide, concave and crescentic 
columellar area, the lower portion of which is bounded by an angle. The 
outer lip is strengthened by a moderately high varix near the margin, much 
lower at the base, and continuous with the angle bounding the columellar 
area. The aperture is very oblique and semicircular, the outer margin 
being deeply arcuate, the inner somewhat straightened. The columella is 
rather broad, with a shallow furrow on its face; and the outer edge is 
somewhat elevated near the insertion, leaving, in the type specimen, a 
shallow crevice behind it, not visible in younger shells. 

Length 5.7, diam. 5.7 mm. 


602 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Uruguay River, at Paysandt, Uruguay. Types, No. 103,050, A. N.S. P. 

Development.—The smallest specimens seen measure 3 mm. diam., 
2.8 high. The peripheral flattening is already weakly perceptible. There 
is no trace of a basal angle or columellar area, but the columella is very 
wide, almost semicircular, with a deep excavation in its face. The angle 
bounding the columellar area is developed very late, appearing only on 
the last whorl. 

This species is described from four specimens, none of them perhaps 
completely mature. The shell figured is almost mature, but lacks the 
post-variceal contraction of the lip, which would probably be acquired. 
Two of the shells have a peripheral brown band, fading out at the edges, 
and one has a second fainter band on the outer part of the base. 

Compared with P. zhering?, this species differs by its somewhat biangular 
shape, the lower varix and the coloration. PP. Jaysanduanus differs more 
radically by its columella. 


LITHOCOCCUS gen: nov. 


Shell globose, thick, sculptured with strongly developed spiral ribs, the 
upper ones spinose ; composed of 4 to 5 convex whorls. Operculum cor- 
neous, subcircular, composed of 3 or 4 whorls, the nucleus near the cen- 
ter. Dentition Amnicoloid; central tooth with 5 to 7 denticles on the 
cusp and 3 basal denticles on each side. Inner lateral tooth with 13-14, 
next with about 16 denticles. Type L. multicarinatus. 

This genus differs from the Lethoglyphine and Potamolthus by the 
operculum. The penis has not been examined. 

LITHOCOCCUS MULTICARINATUS (Miller). Lzthoglyphus multcarimatus 
Miller, Malakozoologische Blatter, n. F., I, p. 157, Taf. 15, f. 4. Rio 
Cayapas, Ecuador, abundant on rocks. 


PREG yO pe. 
Family SPH42RIID 2 Dall. 


The family SAheriide@ is represented in South America by four genera: 
Spherium, Muscuhum, Eupera and Prstdium. Doubtless the last two 
genera will prove to be generally distributed and numerous in forms, 
fL:ufera in tropical, Pesed@ium in temperate and cold regions; but up to this 
time only a few have been described. The list of species described from 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 603 


south of the Equator, compiled in the course of work on Patagonian forms, 
is here given for the convenience of those who have occasion to study the 


group. 
List OF SOUTH AMERICAN SPHARIIDA. 


SPHARIUM AEQUATORIALE Clessin, Malakozoologische Blatter, n. F., I, 
1879, p. 176, Taf. 11, figs. 4-6. 

Rio Pedro, Val de Chillo, Ecuador. Length 9, alt. 6, diam. 3.5 mm. 
Referred by Clessin to the group Corneo/a. 

MUSCULIUM ARGENTINUM (d’Orbigny). See below. 

MUuSCULIUM PATAGONICUM Pils. See below. 

EUPERA BAHIENSIS (Spix), Testacea Brasil., 1827, p. 32, pl. 25, figs. 5, 6. 
Spherium bahiense Spix, Prime, Monograph of American Corbi- 
culidze, 1865, p. 53, fig. 52. 

Bahia, Brazil. 

EUPERA MODIOLIFORMIS (Anton). Spherium modioliforme Anton, Prime, 
Monograph American Corbiculidz, 1865, p. 54. Pes¢dium moqguind- 
anum Bet. 1855. Prstdium diaphanum Hald., 1841. 

Venezuela, Brazil. 

EupPERA TUMIDA (Clessin). Lzmosina tumida Clessin, Syst. Conchylien 

Cabinet, Cycladeen, p. 246, pl. 46, figs. 5-8. 
Bahia, Brazil. 

PISIDIUM MAGELLANICUM (Dall). Corneocyclas magellanicus Dall, Bull. 
Mus. Comp. Zool., vol. 43, October, 1908, p. 411. 

Magellan Straits, in 61 fathoms ; Rio Chico to base of the Andes. 

PISIDIUM OBSERVATIONIS Pils. See below. 

PisIpIUM PATAGONICUM Pils. See below. 

PISIDIUM STERKIANUM Pils., Proc. Acad. Nat. Sci. Phila., 1897, p. 291, 
pl. 6, figs. 1-4. 

Montevideo, Uruguay. Length 6, alt. 5, diam. 3.8 mm. 

PISIDIUM DORBIGNYI Clessin, Conchylien Cabinet von Martini und 
Chemnitz, 2te Aufl, Cycladeen, 1879 ?, p. 62 (new name for Cyc/as 
pulchela VOrbigny, Voy. dans l’Amér. Meérid., Moll., p. 568, pl. 83, 
f. 8-10, not of Jenyns). 

Maldonado, Uruguay. Length 3 mm. 

PIsIDIUM VILE Pilsbry, Proc. Acad. Nat. Sci. Phila., 1897, p. 292, pl. 6, 

figs. 17-20. 


604 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Montevideo, Uruguay. Length 2.6, alt. 2.4, diam. 2mm. Near the 
following species, but shorter. 

PisipIuM GLOBULUS Clessin, Malakozoologische Blatter, n. F., X, 1888, 
Pp. 173: 

Taguara, State of Rio Grande do Sul, Brazil. Length 3, alt. 2.5, 

diam. 2 mm. 

PISIDIUM CHILIENSE (d’Orbigny). Cyclas chiliens?s dOrb., Voy. dans 
l’Ameér. Meérid., Moll., p. 568, pl. 83, figs. 11-13. 

Concepcion, Chili. Length 5 mm. 

PistpruM FORBEsII (Philippi). Cyc/as forbesi Phil., Malakozoologische 
Blatter, XVI, 1869, p. 41. Pfeiffer, Novitates Conchologice, III, p. 
489, pl. 105, figs. 15-17. 

Bolivia alta (Forbes); Lake Titicaca (Raimondi). Length 7.5, alt. 

6.5, diam. 4 mm. 

PISIDIUM BOLIVIENSE Sturany, Nachrichtsblatt d. deutschen Malako- 
zoologischen Gesellschaft, 1900, pp. 56, 57, Taf. 1, figs. 1-7. 

Bolivia, at Machacamac, between Chililaya and La Paz (Countess von 

Bayern). 

Length 7.8, alt. 6.4, diam. 3.6 mm. 
NOL eG G ae Oe Weovoamie 
oe uit. adie ae ecole we 


Near P. forbest?, but lower, more oval, with less projecting beak. 

PISIDIUM LAURICOCH (Philippi). Cyclas daurtcoche Phil., Malak. Blatter, 
XVI, 1869, p. 41. Pfeiffer, Novitates Conchologicz, III, p. 489, pl. 
105, figs. 12-14. 

Lake Lauricocha, at head of the Marafion River. Length 7, alt. 6, 

diam. 4 mm. 

Pistp1uM wort Clessin. P. wolf Clessin in Miller, Malak. Blatter, n. 
F., I, 1879, p. 178, Taf. 11, figs. 7-9. “Clessin, Conchylien @abinet, 
Cycladeen, p. 268. 

Rio Pedro, Val de Chillo, Ecuador. Length 5, alt. 4, diam. 2.5 mm. 

Very inequilateral. 

PisIpIuM DAvisI (Bartsch). Corneocyclas davist Bartsch, Proc. U. S. Nat. 
Mus., XX XIII, 1908, p. 681. 

Chanchan River, Ecuador. Length 5, alt. 4, diam. 2.7 mm. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 605 


MUSCULIUM PATAGONICUM sp. nov. 
(Plates XLVIa, Fig. 8; XLVII, Figs. 1-7.) 


The shell is thin, nearly equilateral, pale straw-yellow, glossy, finely 
striate. The beaks are low and broad, the embryonic stage marked off by 
a contraction or gutter. Anterior end almost symmetrically rounded; pos- 
terior end slightly flattened or subtruncate. Hinge-line arched. Cardinal 
teeth very minute, double in the right, single in the left valve. Lateral 
teeth very short, triangular, single in the left, double in the right valve. 


Figs. 6,6a. Length 8, alt. 6.6, diam. 4.3 mm. 35 miles above Sierra Oveja. 
“6 4,5 “ 8.8 4a 6.8 “ 4.5 “a 25 “c ‘ “ «c 


ce 9 ‘e 7.2 ee 5 a 50 oe “cc “e ‘e 


Springs and small streams along the Rio Chico de la Santa Cruz, from 
15 to 50 miles above the Sierra Oveja. Types from 50 miles above the 
Sierra Oveja (Pl. XLVIa, fig. 8). 

This species is closely related to Musculium argentinum (d Orbigny), 
but constantly differs from that by having the posterior end less abruptly 
truncated, and the beaks flatter, not so full. Figs. 2, 3, 5 are not very 
good. Figs. 6, 6a and 7 show the shape better. Fig. 1 well shows the 
teeth as seen in a partly open shell. Eight lots are before me, from as 
many springs and streams, at distances of 15, 25, 30, 35 and 50 miles 
above the Sierra Oveja. The examples from farther up are the largest 
and are remarkably well developed in every way (Pl. XLVIa, fig. 8). 


MUSCULIUM ARGENTINUM (d’Orbigny). 
(Plate XLVIa, Figs. 6, 7, 7a.) 


Cyclas argentina d Orbigny, Mag. de Zool., 1835, p. 44; Voy. dans l’Ameér. 

Meérid., Mollusques, p. 568, pl. 83, figs. 5—7 (Montevideo). 
Spherium argentinum d’Orb., Strobel, Mat. Malacostat. Argent., p. 77. 

Not Pistdium argentinum Clessin, Conchyl. Cab., p. 63, fig. 2a. 

D’Orbigny’s figures of this species are very unsatisfactory. Clessin has, 

I believe, entirely misunderstood them. His Pes¢dtwm argentinum may pos- 
sibly be P. sterktanum Pils. For the purpose of affording a basis for com- 
parison with Argentine and Patagonian species, I figure two topotypes, an 
adult and a half-grown shell, collected by Dr. W. H. Rush, U.S.N., from 
a creek in the Prado, Montevideo. 


606 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


The shell is fragile, olive-gray when full-grown, the young ones grayish, 
with a yellow zone at the basal edge. The ends are more abrupt than 
in MW. patagonicum, and the beaks fuller. The teeth are decidedly more 
delicate and compressed than in AZ. patagonicum. 


Pl. XLVI¢; fe. 7, 72. Lenethio alt 7-3, diam, 5 mim: 
iT CL Ta, U6! 53, “G42 3) 2.9 immature: 


Strobel reports this species from San Carlos, Province of Mendoza, 
Bahia Blanca and Carmen de los Patagones. He gives the measurements, 
length 9, alt. 7.5, diam. 6 mm., for an example from the last named locality. 

From the Rio Camaguan, Rio Grande do Sul, Dr. von Ihering sent a 
single specimen similar to AZ. argentinum, except in being shorter and 
more globose; length 7.9, alt. 7, diam. 5.2 mm. If such proportions 
characterize a race in that river, it will probably be considered as speci- 
fically distinct. 

PISIDIUM MAGELLANICUM (Dall). 
(Plate XLVII, Figs. 12-16.) 


Corneocyclas magellanica Dall, Bulletin of the Museum of Comparative 
Zoology, Vol. 43, October, 1908, p. 411. 

“Shell small, whitish, with an olivaceous smooth periostracum, low, 
wide beaks and polished surface, with faint concentric indications of three 
or four resting stages; form inequilateral, anterior end shorter, bluntly 
subtruncate ; base evenly rounded; posterior end slightly attenuated and 
rounded; external sculpture of faint incremental lines, chiefly obsolete 
between resting stages ; interior smooth, white ; hinge of right valve with 
a single feeble horizontal tooth directly under the beak, and two well- 
developed lateral teeth rather distant from the beak, the posterior lateral 
stronger. Length of shell 3.5, of posterior end of shell 1.8; height 2.5 ; 
diameter (of both valves) 2 mm.” (Dall). 

Magellan Straits in 61 fathoms, ‘‘ Albatross” Station 2778. ‘A single 
right valve, evidently washed into the sea from some stream” (Dall). 

Springs on the Rio Chico de Santa Cruz, fifteen (Pl. XLVII, figs. 15, 


16) and twenty-five miles above the Sierra Oveja; Rio Blanco, at base of 
the Andes; springs near base of the Andes, 65 miles north of the Rio 
Chico, 2400 ft. elevation (Pl. XLVII, figs. 12-14). 

Dr. Dall, who kindly compared specimens from the last locality men- 
tioned above with the type of P. magelanicum, states that they agree 
almost exactly and, in his judgment, are the same species. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 607 


In the fresh specimens from 65 miles north of the Rio Chico the right 
valve has below the beak a horizontal arcuate tooth, with a straight 
oblique tooth above it nearer the anterior (short) end. The laterals appear 
to be smooth. The left valve has a rather long slender tooth, lower and 
angulated in the middle, the anterior ramus stouter and longer than the 
posterior. The lateral teeth arise under the visible part of the umbones 
(while in P. Jatagonicum they arise beyond it). They are high and tri- 
angular in profile (fig. 16). The shells are light olive externally, with 


Fic. 18. 


P. magellanicum, 65 miles above Rio Chico. Interior of right and left valves. 


several darker concentric streaks. The largest shells measure, length 4.9, 
alt. 4, diam. 2.7 mm. 

Specimen from a spring 25 miles above the Sierra Oveja are similar, 
except that the lower cardinal tooth of the right valve is stouter. One 
opened contained eleven young ones about 1.6 mm. long, almost filling 
the cavity. 

The teeth are practically identical in specimens from six lots examined. 


PISIDIUM PATAGONICUM sp. nov. 
(Plate XLVII, Figs. 8-10.) 


The shell is pale buff, glossy, very finely striate, with low, wide, smooth 
and glossy beaks ; strongly inequilateral, the anterior end very short and 
rounded, base evenly convex, posterior end narrow and somewhat pro- 
duced. Interior white. Cardinal teeth are excessively weak and low, 
nearly effaced. There is a very low, horizontal, rudimentary tooth in the 


608 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


right valve, a low short one in the left, with the scarcely discernible trace 
of another anterior to it. These teeth, especially the anterior one, are too 
distinctly defined in fig. 10. Lateral teeth very short and moderately 
strong, distant from the beaks. 

Length 4.9, alt. 4.3, diam. 3 mm. 

Springs on the Rio Chico, fifteen miles (type loc.) and thirty miles above 
the Sierra Oveja ; twenty-five miles below the Rio Belgrano; and in the 
Arroyo Eke, near the head waters of Spring Creek, 2400 ft. elevation. 

This clam differs from P. magel/anicum by the shorter anterior end, short 
lateral teeth remote from the cardinals, the anterior laterals standing at an 
angle approaching 100° with the posterior laterals, on account of the curva- 
ture of the anterior margin. In P. mageHanicum the angle of divergence 
of the teeth is decidedly greater, and they are longer. The cardinal teeth 
are almost obsolete in P. Jafagonicum, not projecting above the level of 
the hinge. 

In the type lot, as well as in all the specimens from springs recorded 
above, the surface is straw-yellow and the striation fine and even, without 
periodic lines indicating growth-arrest. Inspecimens from small streams 
in the same region the shell attains a greater size, up to length 6.9, alt. 
5.8 mm., and is marked externally with several darker concentric streaks, 
indicating periods of growth-arrest ; the color is generally paler. This 
form, which may be called var. zouzfer, is figured on Plate XLVIa, fig. 9. 
It is from small streams on the Rio Chico fifteen and twenty-five miles 
above the Sierra Oveja. 


PISIDIUM OBSERVATIONIS sp. nov. 
(Text fig. 19.) 

The shell is inequilateral, the beaks low and wide, anterior end very 
short, broadly rounded, posterior end narrow, rounded. Surface glossy, 
olive, drab or yellowish, marked with several impressed and darker rest- 
ing periods. Interior bluish-white. Cardinal teeth: in the right valve 
there are two narrow teeth, parallel, oblique and contiguous. In the left 
valve there is one nearly straight horizontal tooth, lower and thinner near 
the middle. The lateral teeth are rather long and not remote from the 
beaks, single in the right, double in the left valve. The interlocking sur- 
faces of these teeth are more or less granulous. 

Length 4.8, alt. 4, diam. 3 mm.; sometimes larger, length 5.1 mm. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 609 


Near the Mount of Observation (below the mouth of Santa Cruz River). 
This species is chiefly distinguished by its cardinal teeth, which differ 
constantly from those of the other Patagonian Pisidia. 


Fic, 19. 


Pisidium observationis. Interior ot right and left valves. 


Family MUTELIDA2. 
Genus ANODONTITES Bruguieére. 

Anodontites Brug., Journ. d’ Hist. Nat. Paris, I, 1792, p. 131 (for 4. cris- 
patus Brug.). 

Patularia Swainson, Malacology, 1840, pp. 287, 381 (for P. ovata Swains. 
= trapesialis Lam. and P. rvotundatus Swains. =? Anodonta wood- 
zana Lea). 

Glabaris Gray, Proc. Zool. Soc. Lond., 1847, p. 197 (for Anodonta 
exotica Lam.). 

Glabarts Simpson, Synopsis of the Naiades, p. 916. 

Patularia Dall, Nautilus, XX, 1906, p. 39 (type P. ovata Swains. implied). 


ANODONTITES PUELCHANUs (d’Orbigny). 


Anodonta puelchana d’Orb., Mag. de Zool., 1835, p. 40; Voy. dans l’Ameér. 
Mérid., Moll., p. 620, pl. 79, figs. 7-9. Doering, Informe Oficial de la 
Comision Cientifica de la Expeditional Rio Negro (Patagonia), 1881, 
Zoologia, p. 74. 


610 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Rio Negro: Marsh of San Xavier (d’Orbigny); 12 leagues from Chichi- 
nal (Roca Exped.). 


Genus DIPLODON Spix. 
DIPLopon pataconicus (d’Orbigny). 


Umo patagonica a’ Orb., Voyage dans l’Amér. Mérid., p. 610, pl. 70, figs. 
I-4. 
Rio Negro. 
DIPLODON FRENZELLI (Ihering). 
Uno frenzellit v. ther., Archiv fiir Naturgeschichte, 1893, p. 3, pl. 4, fig. 12. 

Rio Negro. 

It may be well here to correct the nomenclature of an allied genus of 
the La Plata and Amazon basins, formerly known as Castalia Lam., 1819. 
This name was believed to be preoccupied by Savigny, in Vermes, and 
Tetraplodon Spix, 1827, has been substituted for it. 

The late Professor Eduard von Martens wrote to me under date of 18 
Oct., 1893, as follows: ‘‘ Concerning Casfalia, the date of Savigny’s genus 
of Annelids is given as 1817 in Agassiz’s ‘Nomenclator,’ it is true, but I 
am not sure that this is correct. I find Savigny’s genus first in his Sys- 
tem of Annelids, which is said to have been published in 1820, whereas 
Castaa Lamarck was published in 1819, vol. V, part I, of Lamarck’s first 
edition [of the 4uimaux sans Vertébres}. 

“P.S. I have consulted in these days the original edition of L. Agas- 
siz’s Nomenclator and I find concerning Casta/a the note : 

“* Castalia Sav., Syst. annélid., 1817. Savigny Systéme des Annelides, 
présenté a l’Acad. des Sci. en 1817, publié en 1826.’ 

“It is true that there is also an edition of the same work, in folio, 
which makes part of the large ‘ Description de l’Egypte,’ and to which in 
Engelmann’s Bibliotheca Zoologica, vol. I, p. 581, the date 1820 is given. 
By general consense the date of publication and not the date of finishing 
a manuscript and presenting it to a learned body is accepted as fixing the 
priority. I come to the conclusion that Cas¢a/ia Lam., 1819 can stand 
for the shell, and Casfa/ia Sav. among the Annelids is to be changed.” 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 611 


Il. 


NOTES UPON THE CHARACTERISTICS AND ORIGIN OF 
THE. NON-MARINE MOLLUSCAN FAUNA OF 
SOUTH AMERICA.! 


In the following synopsis I have limited myself to a brief consideration 
of data derived solely from mollusks. This course is not due to any 
underestimation of the value of other groups in biogeographic work ; but 
rather because conclusions drawn from a group known to me at first 
hand have a certain value which would not attach to borrowed data. The 
classification used herein is that of the Manual of Conchology so far as 
the groups have been considered in that work.” 

It must constantly be borne in mind by those comparing the distribu- 
tion of non-marine mollusks with that of vertebrate groups, that not 
only has evolution proceeded more slowly in the former, but migrations 
have been slower. Thus, when a Pliocene communication was established 
between North and South America, there was a rapid and extensive 
invasion of both areas by mammals ; but the molluscan invasion was very 
much slower and never extended nearly so far. Land and fresh-water , 
mollusks are restrained by conditions which affect mammals and birds far 
less, such as areas with little forest, unsuitable or very scanty rock on the 
surface, or short river systems, not well connected. 

Any inquiry into the antecedents of a fauna leads to the question of 
where its component groups had their rise. The rarity of land and fresh- 
water shells as fossils, and the great antiquity of the family groups, renders 
this question very intricate. The origin of many groups is still quite un- 
known; yet most of the larger families of land-snails, and a few of the 
fresh-water groups may be traced back with considerable certainty, if not 
to definite centers, at least to extensive areas of evolution. 

The several origins of air-breathing gastropods from marine groups — 
from the Opisthobranch stock, the Rhipidoglossa and the Tzenioglossa 


1 For bibliography see H. von Ihering, Archhelenis und Archinotis, Leipzig, 1907. A. Ort- 
mann, Princeton University Expeditions to Patagonia, IV. T. Arldt, Die Entwicklung der Kon- 
tinente, Leipzig, 1907 ; bibliography on pp, 622-631. 

*The family groups of land snails almost all differ widely in contents and limits from those 
of Fischer’s Manuel and other systematic works; a fact of first importance in dealing with the 
distribution of the groups, and the relationships of faunas. 


612 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


—reach far back in Palaeozoic time. We have no data bearing upon either 
the time or place of these events. 

I. We have first to do with a fauna composed mainly of the Orthure- 
throus land-snails '— forms which are structurally but a step removed from 
the aquatic pulmonates, and now forming an insignificant element in conti- 
nental faunas, though still dominant in the islands of the central Pacific. 
The families Vallonide, Enide, Pupilide, Partulide, Ferussacide, 
Amastrida, Achatinellide and Tornatellinide are remnants of this fauna, 
which was doubtless once nearly or quite world wide, and probably attained 
its acme in Paleozoic time. The Heterurethra (Szccznede, etc.) doubt- 
less existed in this early fauna, as well as the Aulacopoda (£7dodontide 
are known from the Carboniferous), and the Hlefcenzde. Of the fresh- 
water forms probably represented in this fauna, we may mention the 
ancestral stock of fresh-water pearly mussels, the Cyvevacea, the ancestral 
Melanopside and Melaniide, and the Lymnaide. With the rise of the 
Sigmurethrous snails, the land-snails of this primitive fauna declined in 
all continental areas. 

One of the most remarkable features of the South American fauna is 
the extreme scarcity of these primitive Orthurethrous land-snails. This 
group is represented only by a few Pufpillide and Ferussacide, probably 
derived from Middle America in the Tertiary, and closely related to Antil- 
lean and Mexican species. 

The origin and early differentiation of the Sigmurethrous land-snails is 
unknown. At the time of their appearance as fossils, in the late Cretaceous 
and Eocene, the modern families were already more or less clearly blocked 
out, so far as they are represented by known fossils. From the evidence 
at hand, derived from the distribution of the groups in the recent fauna, 
and as Cretaceous and Tertiary fossils, it appears that the evolution of 
these families had proceeded during Mesozoic time in two chief areas, for 
which we may use terms proposed in another connection by Dr. Theodore 
Gill. 

II. Cenogeic or northern fauna, occupying old land areas in North 
America, Asia and Europe, —what is now the Holarctic and part of the 
Oriental realm, with part of the Neotropical (the Antillean-Central Amer- 
ican continent). Leading families evolved on this area or areas follow ;” 


‘See Manual of Conchology, XX, Introduction. 
? The groups of low type continued or derived from the preceding fauna are not included. 


PILSBRY : NON-MARINE 


MOLLUSCA OF PATAGONIA. 613 


those which appear to have radiated from the Antillean Continent are 


indicated by the letter A. 


Unionidae, Megaspiridea, 
Pleuroceratide, Urocoptide A, 
Viviparide, Testacellida, 
Diplommatinide, Zonitide, * 
Cyclostomatide A, Limacide, 
Proserpinide A, Arionida, 
Lymneime, Philomycide, 
Helcide, Oleacinide A. 


Clausilide, 

Ill. Logeic or Southern fauna, which occupied chiefly the Gondwana 
continent, including a large part of South America, tropical and south 
Africa, and stretching in a great arch, possibly at no time perfect, to penin- 
sular India and Australia. Here were evolved the families : 


Mutehde. Achatinide. 
Etheride. Afperida. 
Ampullaride. Rhytidide. 
Chilinide. Streptaxide. 
Acavide. Circinaride. 
Strophocheitlide. Veroniceliide. 
Bulimulide. 


The South American fauna is largely made up of groups of typically 
Eogzic or Southern origin, but there are also northern forms, derived 
from Middle America (‘ Antillia’’), and a few groups of ancient and 
unknown origin. These several elements are as follows. 


I. PRIMITIVE GROUP. 


Famulies of very Ancient and Unknown Origin and World-wide Distribu- 
tion, and Isolated Autochthonous Families of Eogeic Origin. 
Circinaritde. Northern South America and temperate North America. 
Bulimulide. Autochthonous; formerly spread to Australasia and now 
invading North America. 
Strophocheitide. Autochthonous. 
Endodontide. \‘Norld-wide, on all continents and islands. 


1 Primitive Zonitide were probably evolved at a very early time, but the group attained its main 
development in the Cenogzic faunas. 


614 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Succinetde. World-wide, on all continents and islands. 
Chilinide. Autochthonous. 
Ammnicolide. On all continents. 

‘The ancestral stocks of these families probably formed the earliest 
fauna of non-marine mollusks in South America. Some of the families 
are known, in other regions, to have been established in Palaeozoic times ; 
and it is likely that as early as that they were already found in South 
America. All of them are sharply isolated groups. 

The Circinariide seem to have remote affinity to Riytdide and Strep- 
taxtde —both of which evolved in the southern hemisphere of the Old 
World. In North America this family is probably intrusive, being repre- 
sented by a single genus also found in South America. 

The Strophocheilide have relations —though not close— with a series 
of genera (4cavide) now found in south Africa, Madagascar, the Sey- 
chelles, Ceylon, Moluccas, Australia and Tasmania. The radiation of 
this scattered group from the Palaeozoic Gondwana continent of Neumayr 
seems a reasonable, in fact the only tenable, hypothesis. 

The Bulimulide have descended from the Holopod stock, probably 
also of Gondwana Land, since we have no evidence of any other ancestry. 

Endodontide and Succineide are world-wide groups, even on the most 
remote islands. Their early presence in South America is therefore likely. 

The C/ilinid@ represent an isolated branch of the primitive Basomma- 
tophora. No scrap of evidence has been brought to light to show that 
they ever existed elsewhere than in South America; and at present we 
have every reason to believe that there they invaded fresh water from 
the sea. 

The Pectinidens group of Lymueide and the Aucyde@ are evidently 
traceable to some very early radiation. Adequate data upon the soft 
anatomy and relationships of the forms of the southern hemisphere do not 
now exist. | 


IJ. THE ARCHHELENIC GROUP. 
Families which for the Greater Part are Represented i the 


Tropical African Fauna by a far Greater Diversity of 
Forms than in the South American. 


The hypothesis of an Africo-Brazilian continent of Palaeozoic and Meso- 
zoic times, first sketched out on purely palzeontological grounds, and ably 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 615 


advocated by Dr. von Ihering from the evidence of the fresh-water fauna, 
is essential to any rational explanation of the distribution of land and 
fresh-water mollusks. 

The following South American groups are common to the tropical 
African radiation center. Terrestrial groups are marked with an asterisk (*). 
* Streptaxtde (fig. 21). 

* Achatinide (fig. 20). 

* Veronicellida. | 

Planorbine (South American Planorbis and Plestophysa close to African 
Planorbis and Lstdora). 

Ampullaride (genera with corneous opercula, fig. 22). 

Melanide (nearest to African forms). 

Mutelide (fig. 23). 

Etheride (fig. 24). 

Spheride, of the genus Eupera. 

Such of these groups as are represented in the West Indies and sub- 
tropical North America, have evidently, from their distribution, relation- 
ships and the greatly diminished number of genera and species, been 
derived from South America, rather than from some common source, such 
as Archhelenis. None of them are present as Mesozoic or Tertiary 
fossils in North America,* and nearly all of them are likewise absent from 
European deposits. 

There is a good deal of evidence that most of the above groups arose 
in the eastern hemisphere and migrated westward, and little evidence or 
none that any of them moved in the opposite direction. 

The Streptaxide, Achatinide, Ampullariide, Melanide and Mutehde 
are far more diversified in Africa than in South America. It seems that 
several Gondwana subfamilies were not present in the fauna of Archhelenis, 
or at least did not extend so far west as to reach South America, though 
they must date back at least as far as some other subfamilies which are 
represented both in South America and Africa. 

The primitive stock of fresh-water mussels seems to have early split into 
two phyla: the one, M/ute/ide, evolving in the south, on the Gondwana- 
Archhelenis continent, the other, U/zzonzde, in the north, in North America 


1The Planorbine are found on all continents, but those of South America are obviously most 
closely related to the African forms. 


616 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


and Asia. The occurrence of both families in the same waters is evidently 
due to migrations, which ensued after the families had become differ- 
entiated. The Mufefde attain their northernmost point in the Panuco 
River, in northeastern Mexico, where the family is represented by one 
species of the South American genus 4odontiles. 

Simpson and Germain refer a few African forms to the South American 
genus Dip/odon, and Germain has called attention to the similarity of the 
African Psendavicula to the South American Prisodon or Hyria. If the 
resemblance of the shells proves to be supported by the soft anatomy, 
then this family at least will be evidence of an eastward migration in 
Archhelenis. At present the evidence is insufficient. The possibility of 
convergence in shell-form must be taken into account. Most if not all 
African Uniontde, like the African Cyclostomatida, Zonitida, etc., are 
clearly of Oriental derivation. These are northern Canogeic families 
which have invaded Africa during the Tertiary. 

The maps following illustrate the distribution of part of the Archhelenic 


groups. 
Fic. 20. 


Distribution of the land-snail family Achatinide. The numerals represent the number of 
genera in each area. 


The autochthonous families, together with the Archhelenic group, make 
up the mollusk fauna of the Brazilian plateau; but the more isolated and 
peculiar, presumably older, genera have outlying forms in the Guiana- 
Colombian center, indicating a former unity of the northern and southern 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 617 


massifs. This connection of the Brazilian and Guiana-Colombian areas 
must have persisted long after the Archhelenic period, for distinctively 


Distribution of the land-snail family Streptaxide. 


Fic.) 22: 


Distribution of fresh-water snails of the family Ampudlaritde, having the operculum wholly corneous. 


American genera had been differentiated. It wads interrupted prior to the 
union with the Antillean-Mexican continent, since the genera of that area 


618 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Fic. 23. 


Nan 


90 


&\ 
Distribution of the bivalve family Mutehde. 


Fic. 24. 


Distribution of the bivalve family Erheriide. 1, Miilleria;2, Bartlettia ; 3, Etheria; 4, Pseudo- 


milleria. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 619 


did not gain access to the eastern Brazilian plateau. If the conclusion that 
the Amazon valley was a Cretaceous bay or strait connecting the Atlantic 
and Pacific be well-founded, then the common dispersion center of this 
old fauna may have been in land now lost under the Atlantic. The facts 


Fic. 25. 


Distribution of Tomigerus, Anostoma and Auris, three old genera common to the Brazilian and 
Guiana-Colombian centers (probably all are more widely distributed inland). 


Fic. 27. 


Distribution of Odontostomus. Distribution of (1) Macrodontes, (2) Anctus, 
(3) Hyperaulax and Bonnanius. 


of molluscan distribution favor the view that in Archhelenic times the 
Amazon valley formed a gulf opening westward, wherein Cretaceous deposits 
were laid down; eastern Brazil north to Guiana bounding this gulf on the 
east, until the depression of the Atlantic basin marked the close of Mesozoic 


620 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


time. Such a hypothesis finds support in the presence of genera of the 
old Brazilian type on the island of Fernando Noronha. Numerous.very 
peculiar land-shell genera, such as those tabulated in fig. 25, have a dis- 
tribution not readily explicable on any other hypothesis; while in still 
other cases, allied but generically distinct groups are similarly distributed. 
It may be noted that Bates has remarked that the Para insect fauna is 
essentially Guianian.* 

Figs. 26, 27 show the distribution of several old land-snail genera of 
the Brazilian center. Fig. 25 that of several genera common to the 
Brazilian and Guianian centers. 

That the Amazonian valley ever formed an upper Cretaceous strait 
connecting the south Atlantic and Pacific, as claimed by Dr. Ortmann,’ 
seems rather improbable. 

The Guiana-Colombian elevation has beena secondary radiation center for 
a number of genera of autochthonous South American families, chiefly the 
Bulimulide. The arboreal groups Oxysty/a and Corona have spread south 
of the Amazon into eastern Brazil (fig. 28), while numerous other genera 
from this center are restricted to the north and west as in fig. 29. The 
Guiana-Colombian area also served as a secondary center for Antillean 
and Mexican groups, entering by way of the Caribbean elevation and that 
in the Panamic region. These groups have spread southward as in 
figs. 30-34. 

A hypothesis has been advanced by Dr. Ortmann® that Archhelenis of 
the Lower Cretaceous was succeeded in the Upper Cretaceous by a land 
bridge from tropical Africa to an area covering Guiana, the Caribbean Sea 
and the Mexico-Antillean region (the so-called Mesozonia), separated from 
the Brazilian island. By this hypothesis, Antillia should be as rich in 
African or Archhelenic types as Brazil, and in fact should show a closer 
resemblance to the African fauna due to the later connection. This is 


' Naturalist on the Amazons, I, p. 109. 

* Proc. Amer. Philos. Soc., XLI, p. 381, and in later articles. Dr. Ortmann’s paleogeographic 
maps incline strongly towards what Fiske would call the “wet theory.”” It is not likely that all 
beds reported as Upper Cretaceous were below the sea at any one time. To map an Upper Cre- 
taceous epicontinental sea to include all the exposures of a formation which included so long a 
period of time is not warranted by our present slight knowledge of the stages of the South 
American Cretaceous. 

* The Geographic Distribution of Freshwater Decapods and its Bearing upon Ancient Geography. 
Proc. American Philosophical Society, 1902, pp. 380, 381. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 621 


exactly contrary to the actual facts of molluscan distribution. All African or 
Archhelenic forms which exist in the Antilles are unequivocally of the South 
American type, and certainly indicate that there was no later migration 
or communication from Africa in the north. There seems little evidence 


Fic. 28. Fic. 29. 


Distribution of Orthalicine.  Oxystyla Distribution of Plekocheilus, a genus of 
spreads throughout the black area except in Guiana-Colombian origin, spreading south- 
the Antilles. Number of genera in each ward in the late Tertiary. 


district indicated by numerals. 


for the Upper Cretaceous ‘“ Mesozonia,” mapped by Dr. Ortmann, and 
there are very strong reasons for holding that no such land existed. 

Dr. von Ihering! holds that the subsidence of the Brazil-Ethiopian 
continent began in the north during the Cretaceous. 


* Archhelenis und Archinotis, P3387: 


622 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


III. 


Middle American (Mexico-Antillean) Forms, of Later Date in South America 
than the Archhelenic Group, in Some Cases Generically Differentiated 
Jvom their Northern Ancestors, but more often Belonging to the 
Same Genera, Therefore Doubtless Traceable to both Earlier 
and Later Migrations Southward. 


Flelicide* (figs. 31, 32). Physide. 

Urocoptide (fig. 33). Cyclophoride (fig. 34). 
Oleacinide (fig. 30). Cyclostomatide. 
Pupilliide. Proserpinide. 
Ferussacide. Flelicinide. 


Lymneide (of the Galba group). 

These intrusive forms from middle America are characteristic of the 
Guiana-Andean region, though a few have attained a wider distribution. 
Streams of migration from and to the Antilles are indicated by the way of 


‘The belogonous and epiphallogonous Helicide of South America are clearly of northern 
origin. Whether such extremely peculiar genera as Solaropsis, Psadara and Macrocyclis also 
belong in the same category, seems somewhat uncertain, although such competent malacologists 
as von Ihering and Fritz Wiegmann place these genera in the Epiphallogona. 

The heavy, large Helices of the Eocene of southern Europe, such as Dewtellocaracolus, Pro- 
thelidomus, Galactocheilus and Fridolinia, may perhaps belong to the group Epiphallogona of my 
arrangement, rather than to the Helicine where I formerly placed them; yet if so, I think the 
supposed relationship to West Indian forms is not especially close. Like the American and 
European species of Ade/opoma, the Epiphallogona probably reached both Europe and America 
from eastern Asia, and from opposite directions. 

Dr. von Ihering (Verhandlungen k. k. zoologisch-botanischen Gesellschaft in Wien, LIX, 
1909, pp. 420-428) has recently referred the belogonous Helices (Epiphragmophora) of Argen- 
tina and southern Brazil to the European genus Helicigona (Campylea auct.); but I do not 
believe that this classification can be sustained. So far as I know, the South American Epiphrag- 
mophoras have the spermathecal duct very short, whereas Helicigona, like all other European 
Belogona, has a very long duct, bearing a long diverticulum, which is bound by a membrane to 
the oviduct. These are important differences, quite sufficient to show that Zpiphragmophora is 
not at all closely related to Helicigona, aside from the different shape of the mucous glands, and 
their removal in Ep:phragmophora from the vagina, upon which they are invariably inserted in all 
European Belogonous Helicide. 

By its short spermatheca, Epiphragmophora differs strongly from all other known belogonous 
Flelicide. In other features it stands nearer to Antillean and North American forms than to 
European. My former treatment of the genus was too inclusive. I would now restrict Zpiphrag- 
mophora to forms having the spermatheca short, removing all of the Mexican and North Amer- 
ican species (which have a long spermathecal duct) from the genus. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 623 


the Caribbean Islands on the east, and on the west the region of the Isthmus 
of Panama, where the interchange of forms has continued to the present 
time. That the middle American elements are far younger in South 
America than the Archhelenic, is shown by their close relationships to 
Antillean and Mexican forms, very few special genera having evolved. In 


Fic. 30. 


Distribution of the Oleacinide. The dotted area stands for the genus Eug/andina only, which 
also occupies Mexico and Central America. Vertical shading in Europe for Tertiary, black for 
recent species of Potretia. 


most of the families only one or very few genera have invaded South 
America out of a large number in the parent lands. Moreover, it is notable 
that they have not extended far south in the east, where the Amazon 
valley has proved a barrier to land-snails. Their distribution has been 
along the Andes, spreading eastward in Bolivia and southern Brazil. 

Figures 30 to 34 illustrate the distribution of middle American groups 
of land-snails incursive in South America. 


624 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


In molluscan distribution, there is strong evidence against the view 
of Ortmann (1902, p. 347) that the northern margin of South America 
formed part of the Antillean continent. Schuchert’s representation of the 
Caribbean Sea as an old permanent basin seems preferable; but his repre- 
sentation of the total submergence of the Antilles in the Middle Cretaceous 


HIGs il 


Distribution of Helicide of the group Belogona Euadenia (one species extends westward to 
eastern Europe). 


and again in the Upper Oligocene’ cannot, I think, be sustained. The 
rich Oligocene beds of Jamaica (Bowden) and Santo Domingo, carrying 
a marine fauna of littoral type, occur at very low levels; and no deposits 
actually known to be Oligocene are found on the higher mountains, which 
I believe were islands in both Cretaceous and Oligocene times. 

The primary region of radiation of the middle American families named 
above is a subject too large for adequate discussion in this place. So 


much is clear: the fauna contains three groups of diverse genesis. The 
‘Bull. Geol. Soc. Amer., XX,_Pl. 95, 97, 1910. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 625 


autochthonous group, such as Oleacinide, Urocoptide, Cerionida, Sagdine 
Cyclostomatide, Helicinide, contains many phylogerontic lines, signalized 
by shells with more or less detached or uncoiled later whorls, sculptured 
embryonic whorls, highly developed, often spinose sculpture, complicated 
internal armature, and the like. These first families of Antillia, now in their 
old age, are related to the families of the northern or Caenogzic area of 
land-mollusk evolution. Some of them, and the ancestors of all, doubtless 
had a much wider range in Mesozoic times. A few, such as the O/eacin- 


Fic. 32. Fic. 33. Fic. 34. 


Distribution of Epiphal- Distribution of Urocop- Distribution of Cyclo- 
logonous Helices in America tide. Shaded area Excalo- phoride in America. 
(exclusive of Solavopsis and dine and Holospirine ; black 
Macrocyclis). area Urocoptine. 


ide and Cyclostomatida, were abundantly developed in Europe as late as 
the Miocene, or even linger in a few forms in the recent fauna. These 
European forms cannot, in my opinion, be looked upon as ancestral to the 
Antillean, but rather as parallel descendants of a common stock derived 
from the north, where the old Scandinavian and North American land 
areas were, at least from time to time, united. 

A second element of the Mid-American lands consists of groups derived 
from the Chinese or east-Asiatic center. Prominent members are the 
dart-bearing and the Epiphallogonous He/icide, the Cyclophoride, Dif- 


626 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


lommatinide (Adelopoma), Clausthida, etc. These forms never have the 
old-age stigmata of the preceding group. They are developed in won- 
derful abundance and virility. Being known in characteristic genera of 
American type (Plearodonte, Cepolis) in the Floridian Oligocene island, the 
advent of the group in middle America must have been much earlier. It 
could hardly have been later than the beginning of the Eocene, and prob- 
ably was not later than the Upper Cretaceous." 

Finally, we have as the latest faunal element in the Antillean-Mexican 
area, a series of South American forms — Achatinide, Bulimulde, 
Ampullaviide, Melanide, Muteide and some North American forms, 
Unionidae, Pupilide, Zonitide, Polygyrine, etc. These are, with very few 
exceptions, unchanged generically, andsome are specifically identical with 
existing South or North American forms. It is very evident that such 
Archhelenic forms as exist in the Antilles and Mexico were not derived 
directly from the Archhelenic area; they migrated in the later Tertiary 
and Pleistocene from the Guiana-Colombian center. 

Antillia has not been an evolution center for fresh-water mollusks or 
fishes, evidently because it has never been a very large area, and has been 
an unstable one, at one time in form of a continent, again an archipelago, 
hence without river systems of great extent or duration, such as are essen- 
tial to the evolution of a fresh-water fauna. 

There is absolutely nothing in the distribution of mollusks suggesting 
that either South or North America was at any time connected with the 
supposed South Pacific continent, or the Hawaiian group. Even Juan 
Fernandez has a land-snail fauna of Pacific and not South American type. 
The Hawaiian and Polynesian connections with America mapped by Arldt 
(1907) seem quite impossible. 

‘The American Clausilide are thought by Professor Boettger to be related to the European 
Miocene and recent Pyrenean group Laminifera, but they seem to me even closer to the genus 
Garnieria, of the Indo-Chinese center. The Helicinide may have arisen in Middle America from 
an aquatic rhipidoglossate stock, but the very wide distribution of the group in Polynesia and 


eastern Asia suggests that it is a very old one, which probably appeared among the first land- 
snails. 


The Belogonous Helices still exist in high latitudes on both sides of the Pacific, being known 
from Sitka on the American and the Kuril Islands on the Asiatic side. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 627 


ARCHIPLATA AS AN EVOLUTION-CENTER. 


Wallace in 18761 showed that the South American fauna is divisible 
into two subregions which he called the 7vofica/ or Brazilian and the 
South Temperate or Chilian. He calls attention to the affinities of the 
Chilian diurnal Lepidoptera and the Carabidz to North Temperate forms.” 
Dr. H. von Ihering in numerous papers * has recognized the two subregions 
of Wallace as distinct evolution centers. He concludes that these centers, 
Archiplata (that is, Patagonia, southern Brazil, Chili and western Peru) and 
Archibrazil, were long isolated from one another by an arm of the sea. As 
primitive elements of the Archiplatan fauna he mentions the fresh-water 
crab .4:9/ea, the genus Parastacus, and the mollusks Diflodon and Chitina. 
Negative characteristics are found in the absence of the dominant Ama- 
zonian genera of mussels and Ampullariide (which seem to have invaded 
the La Plata drainage area comparatively lately, probably in the Pliocene) 
to which many groups of land-snails might be added. 

The geology of the regions involved is so imperfectly known that we 
have no positive data for or against the hypothesis that an arm of the 
Cretaceous sea extended across the continent, as von Ihering claims. This 
is a question only to be settled by geological exploration of the region, 
which may perhaps show a Cretaceous transgression similar to that which 
involved eastern Mexico and the region northward in the middle Cretaceous. 
Yet the fact remains that, so far as molluscan groups are concerned, there is 
but little evidence of such an isolation of the Archiplatan area. The barriers 
to migration imposed by climate have not been taken into account. The 
Ampullarude are snails that have never, in any region, been able to extend 
beyond a subtropical climate. TheCz/inide (fig. 36) are apparently, like 
the large Lymnzeas in North America, snails which cannot exist in a sub- 
tropical or even a warm temperate environment, however favorable may be 
the conditions of migration. It is instructive, in this connection, to com- 
pare the Lymnzid faunas of Minnesota and Arkansas, which show great 

‘Geographical Distribution of Animals, II, frontispiece and Chapter XIV. 

? Dr. Scharff has suggested an explanation of this peculiarity (American Naturalist, Septem- 
ber, 1909, p. 513), but his hypothesis explains only a few facts. It would involve us in problems 
more intricate than those which it solves. Possibly the systematic relations of the insects in 
question have not been rightly estimated. 


* The more important of these articles have been reprinted in his ‘“ Archhelenis und Archi- 
notis,” Leipzig, 1907. 


628 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


diversity, although favorably situated for migration. Another group which 
is widely distributed in the Archiplatan area, though not confined to it, is 
the Amnicolid genus Léfforidina (fig. 35). The absence of Amnicolidze 
in the Amazon system is probably apparent rather than real, since prac- 
tically no collecting of small or minute mollusks of any kind has been 
done in that vast area. It is likely that Amnicolidze will be found there 


Fic. 35. Fic. 36. 


Known distribution of Lttoridina, a genus Known distribution of Chilinidz, a family 
of fresh-water snails. of fresh-water snails. 


in abundance. D¢A/odon, another genus which Dr. von Ihering considers 
Archiplatan, is found almost all over the continent, and cannot fairly 
beclaimed as of Archiplatan origin. It no doubt arose from the same 
Brazilian (and ultimately Archhelenic) stock as /Zyvia, etc.; but like U/uzo 
in the northern hemisphere, it is a hardy stock not highly evolved in its 
phylum, hence probably old. Compare in this connection the Unionid 
and Pleuroceratid fauna of Alabama with that of Georgia and the Caro- 
linas. In these adjacent areas, which have been continuous land since 
very early times, we have as much difference in the fresh-water faunas as 
has been shown to exist between Archibrazil and Archiplata. Rich faunas 
of fresh-water mussels and gastropods are rarely found in regions like 

1 At Davenport, Iowa, I have found Lymnea stagnalis on logs rafted down the river from 
Minnesota, but the species has not been able to gain a place in this fauna there or farther south ; 


nor have many of the other northern Lymnzide, which must yearly be brought down on drift 
wood during the spring floods. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 629 


southern South America, drained by numerous short, independent rivers, 
owing to the difficulty of migration and the relative impermanence of the 
individual streams. 

The presence of peculiar and strongly individualized land snails of 
Brazilian type (Sca/arinella, Plagiodontes, etc.) in the Sierras of western 
_ Argentina and the now isolated Sierra Ventana, shows that long ago the 
Brazilian fauna extended at least as far south as Bahia Blanca, where a 
fragment has persisted, isolated since the Pliocene at least." 

Taking into consideration the climate, the rarity of large forest areas, 
the aridity of large tracts, and the short, unconnected rivers, we are not 
inclined to give much weight to Dr. von Ihering’s contention that many 
Brazilian groups are wanting in ‘ Archiplata.’’ So far as mollusks are 
concerned, that area has very slight claims to rank as an evolution center. 
I regard the Chilian and Patagonian fauna as an impoverished and slightly 
modified extension of the fauna of the old Brazilian continent. The evi- 
dence for an Archiplatan center may be stronger in the case of Crustacea, 
Oligochzta, plants and insects; but I prefer to leave the discussion of 
these groups to those having first-hand knowledge of them. 

Connected with the Archiplata hypothesis is that of Antarctica, which 
may here be examined briefly. 


AUSTRAL ELEMENTS IN THE SOUTH AMERICAN 
FAUNA. 


The Austral or Antarctic relationships of the South American fauna 
have been somewhat fully discussed in other volumes of this series, and 
a map illustrating the Antarctic continent and its hypothetical former ex- 
tensions may be found in volumeIV. I have to deal here with the evz- 
dence afforded by the non-marine mollusks, which, taken by itself, \eads to 
the following conclusions: (1) There is no evidence that Antarctica was 
ever an evolution or radiation center for non-marine mollusks, though 
there is some evidence showing that it served as a highway for migration. 
(2) There is some evidence of migration from South America to Austral- 
asia, but at present no evidence of a counter movement to South America. 
(3) Nothing in the distribution of mollusks would lead to the hypothesis 


1Dr. Ortmann agrees with von Ihering in isolating a Chilian and southern Patagonian land 
mass of Cretaceous age, but he views it as an extension of Antarctica. The difference is rather 
one of names than of things. Proc. Amer. Philos. Soc., 1902, pp. 379, 381. 


630 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


that South Africa has ever been connected with Antarctica and thereby 
indirectly with southern South America. 

Non-marine mollusks having an Antarctic distribution belong to three 
families. The evidence in each case is briefly as follows : 

1. The Bulimulide, \and snails of South American origin, of which one 
genus (othriembrion) is found in Tasmania and southwestern Australia, 
another (Placosty/us) in New Zealand, New Caledonia, the islands of 
Melanesia and as far east as Fiji. Both of these genera are distinct from 
South American forms, but they are undoubtedly related to the more 
generalized of the South American genera. 


Fre. 37. 


Distribution of the land snail family Bulimulide. The number of genera in each area is indi- 
cated by figures. 


The presence of Budimulde in Australia and Melanesia proves that 
the part of South America connecting with Antarctica was, or had been, 
connected with the old Brazilian evolution center. 

2. The Ammnicolide, a family of fresh-water snails, has one genus, 
Potamopyrgus, in New Zealand, Tasmania and South America. Another 
South American genus, Potamolthus, has its nearest ally in the genus 
Petterdiana of Tasmania and Australia. Both of these genera are exclu- 
sively fresh-water groups. See pp. 548-550 of this report. 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 631 


3. The Naiades or fresh-water mussels found in all of the continents, are 
represented in Australia, Tasmania and New Zealand only by species 
which have been referred to the genus Dzf/odon. This genus is widely 
distributed in South America, especially southward. It is a relatively 
primitive genus and probably arose in South America, which, from the 
number of autochthonous genera, was evidently an old evolution center 
of Naiades. Dzf/odon is unknown in the northern continents. Whether 
the relationship with South American forms claimed for the Australia- 
New Zealand group is well-founded, remains to be confirmed by careful 
comparison of the soft anatomy. 

The family Exdodontide, and Gundlachia of the Ancylide, have been 
considered “Antarctic” groups, but on evidence of slight value. The 
Endodontide are an ancient group, world-wide in distribution. No close 
relationship has been shown to exist between the South American and 
the Australian genera. The former are unknown anatomically, and the 
relations of Australian and New Zealand forms, so far as positively made 
out, are with the groups of Polynesia and Micronesia (Charopfa, Thauma- 
todon, etc.). Certain Tasmanian species may prove to belong to the 
American genus Radiodiscus Pils. See p. 516. 

Gundlachia is found in Australasia, South America, the Antilles, Mexico, 
temperate North America and also the Miocene of central Europe. This 
wide distribution suggests that the genus may have reached the southern 
lands from the north. In the United States it has been found in Cali- 
fornia, Illinois, Ohio, New York, etc., but only at remote intervals and in 
very narrowly restricted areas. It is likely that it will turn up sooner or 
later in the Oriental region and Africa. I hesitate to claim Gandlachia 
as an inhabitant of Antarctica. 

Pond snails of the family Lymnezde also occur in all the Austral 
lands, but South American forms do not seem especially related to Austral- 
asian. While Exdodontide, Gundlachia and Lymnea may have inhabited 
Antarctica, no data upon them now in our possession goes far towards 
proving that they did. 

I can find no evidence to support Hedley’s contention that the Macro- 
ogona (4cavide) of Tasmania and Australia, and the Rhytdide of the 
same regions, New Zealand, New Caledonia, etc., are ‘‘of Antarctic origin.’ 
These groups must have attained their distribution from South Africa to 

' Hedley, Proc. Linn. Soc. N. S. Wales, 1899, pp. 396, 398. 


632 PATAGONIAN EXPEDITIONS: ZOOLOGY. 


Australia by way of the Gondwana continent, leaving isolated genera by 
the way in Madagascar, the Seychelles, Ceylon and the Moluccas. To 
this Palaeozoic and early Mesozoic land the South African Endodontidea, 
Peripatus, etc., may also belong. The evidence for an isthmus connecting 
South Africa and Antarctica, as sketched by Forbes, Ortmann and some 
other palazeogeographers, seems unsubstantial. Nothing in the distribution 
of non-marine mollusks lends it support. 


Showing sources of the South and Middle American mollusk faunas. Early Mesozoic and 
earlier migrations in heavy lines, late Mesozoic lighter lines, Tertiary and later migrations in dotted 
lines. 


The rather large size of the fresh-water mussels and Bulimuhde pre- 
cludes the idea of their distribution as adult organisms except by actual 
land connection. Some embryonic Uxéouide are probably carried by water 
birds, but we do not know that this is the case with Dzp/odon ; moreover 
only short distances can be so traversed, since unionid embryos are known 
to die quickly out of water. It is hardly conceivable that Bulimulid eggs, 
which are smooth and not viscid, should be so carried. The same is true 


PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 633 


of the egg-capsules of Amunicolide. It would be absurd to suppose that 
they could ever be spread by aquatic birds. 

Such evidence as we have favors the view that the connection of South 
America with Antarctica was transitory, hence taken advantage of by but 
few genera of mollusks, all belonging to families richly developed in the 
South American center. So far as non-marine mollusks show, the migra- 
tion from South America of a few species belonging to three families will 
account for all the common elements in the austral lands of the two 
hemispheres. The strong generic differentiation of all the common 
austral groups, with the exception of Pofamopyrgus and probably Dzp/o- 
don, indicates that the connection was of considerable antiquity, probably, 
as Dr. Ortmann holds, not later than Eocene. 

Summary.— The South American molluscan fauna is traceable to two 
sources : an ancient southern continent lying across the south Atlantic 
and enduring from at least Palaeozoic to near the end of Cretaceous time, 
and to Miocene and Pliocene to recent connections with the middle 
American area. Antarctica was not an evolution center for mollusks, but 
there is strong evidence that a few groups passed by the Antarctic route 
to Australasia. ‘ Archiplata,’”’ owing to its physical diversity from the 
Brazilian and Colombian areas, has became a Tertiary evolution center 
for a few groups of Brazilian origin. 

Middle America (Antilles + Central America and part of Mexico) has 
the characteristics of an old evolution center of the northern faunal 
group, its primitive fauna coming from the north, and now showing phylo- 
gerontic features; a later (probably late Cretaceous) element was derived 
from the East Asiatic fauna. Both elements contributed, during the last 
half of the Tertiary, to the South American fauna, and received immi- 
grants in return. 

The “ Nearctic Realm,” so far as the genesis of its faunas is concerned, 
is composite. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XXXVIII. 


Bisse, 12; 10. 
Rigs. 2,22, 26,\3- 
Fig. 4 

Bigg 05 

Figs. 6, 6a 

Figs. 7, 7a, 76 
Fig. 8 


PoraMoLitHus RusHII Pils. Adult stage. Type 
POTAMOLITHUS MICROTHAUMA Pils. Type and a smaller 
specimen. : : . : : ; : 
PoTAMOLITHUS RUSHII Pils. Neanic stage, diam. 3 mm. . 
PoTAMOLITHUS DINOcHILUS Pils. Adult, seen obliquely 
from above . : ; : 
POTAMOLITHUS HATCHER! Pils. Type. ; ; : 
PoTAMOLITHUS DINOcHILUS Pils. Three views of the type 
(fig. 5 represents the same specimen) 
PoTAMOLITHUS DINocHILUs Pils. Neanic stage. 


(VoL. 111) 


PAGE 


599 


597 
599 


595 
594 


595 
596 


ESS 


PQS, 4 
“SAQA 


Cor 
(sag 


re 


HSH SU 
. 6, 6a. 


7, 74: 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PEATE XXxte 


. I, 1a, 16. PoraMoLituus HIDALGO! Pils. Three views of type 
22, 2a: 
Pesa: 


POTAMOLITHUS IHERINGI Pils. Two views of type 
PoTAMOLITHUS JACUHYENSIS Pils. Two views of type. 
PoTaMoLitHus LapipuM (d’Orb.). Neanic stage. Uruguay R. 
iB « ss Adult <“ s 
PoTAMOLITHUS SIMPLEX Pils. Two views of type . 
PoTAMOLITHUS LAPIDUM SuPERSULCATUS Pils. Front and pro- 
file views 


(VOL. 111) 


PAGE 
597 
600 
583 
587 
587 
578 


588 


Figs. I, 2, 2a. 


Bigs 3s 


Figs. 4, 4a, 5. 


Figs. 6, 6a, 64. 


Hig. a7. 


Figs. 8, 9, 9a. 
Figs. 10, 10a. 
Pigs: 11, D1. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPEANATION OF PEATE XL. 


PoraMOLITHUS ORBIGNYI Pils. Cotypes, adult stage . 
eS “ as Small individual ap- 
proaching the adult 
stage 
“a st Neanic stages : 
PoTAMOLITHUS TRICosTATUS (Brot). Three views of 
adult stage 
é a i Gerontic individ- 
ual . 
PoraMoLiTuus conicus (Brot). Adult stage. ; 
PoTAMOLITHUS AGAPETUS Pils. Two views of the type . 
PoTaMOLITHUs BuscuHII (Ffld.). Twoviews, neanic stage. 


Figs, 12, 124,13, 14. ae ot as Adult individuals. 


(VOL. 11) 


PAGE 


582 


582 
582 


593 


593 
581 
578 
580 
580 


an we As (Oa 


Figs. 
Figs. 
Figs. 
Figs. 
Figs. 


Figs. 


Figs. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLI. 


1, 1a, 16. Poramoxiruus syKEs! Pils. Three views of type. 


Pd PALE 


3, 4 5- 


6, 6a. 
RHE 


8, 8a. 
9; ga. 


“ ss ‘““ Gerontic individual . 
PoTAMOLITHUS BISINUATUS OBSOLETUS Pils. Cotypes 
ss ‘ Pils. Two views of type 
- x “Two views of a_ gerontic 
individual. 
PoTAMOLITHUs GRACILIS ‘ ‘Two views of the type. 
‘ «« _viripis Pils. Two views of the type. 


(VOL. 111) 


PAGE 
574 
574 
577 
576 


576 
577 
578 


Figs. 1, 14. 


. PorAMOLITHUS CARINIFER Pils. Front and back views of the type 
. POTAMOLITHUS QUADRATUS “ [ee bOile sa. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XELA:; 


PoTAMOLITHUS PAYSANDUANUS Ther. Front and profile views of 
the type : : 3 : 

is x sINULABRIS Iher. Type and a 
larger specimen. : : ; 

‘ a mmpressus Ther. Front and profile 
views of the type : 

fhe tee 


“ “ 


PoTAMOLITHUS LAPIDUM SUPERSULCATUS. Back view 


. PoTAMOLITHUS FILIPONEI Iher. Profile and front views of the 


type. a. : : : . : 


(VOL. III) 


PAGE 
59° 
5o7 
59 
SR 
592 
588 


573 


ata. re Fen Tee 
a < Al ‘2 4 u 

7 >» ol . a 

peer 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OER PLATE XL: 


Figs. 1,%~4, 16. PoTAMOLITHUS PHILIPPIANUS Pils. Front and back views of the 


“ Ja type. 
Pigs 2: af Young topotype ‘ 
Figs 3) Poramo.itHus BuscHit Dkr. Front view of specimen from Fray 
Bentos . ; : 
Fig. 4. POTAMOLITHUS REBEIRENSIS (?) ' ‘ ‘ 
Figs 5: PoTAMOLITHUS LAPIDUM ELATIOR Pils. Face of type . 


Figs, 6,7, 7a. POTAMOLITHUS REBEIRENSIS 
Figs. 8, 8a. PoTAMOLITHUS CHLORIS 


Fig. 9. POTAMOLITHUS INTRACALLOSUS 
Fig. 10. POTAMOLITHUS PARANENSIS 


ss “of two cotypes 
« Profileand face of the type. 


«Young topotype and the 
type . : é : 


(VOL 111) 


PAGE 


601 
601 


581 
585 
588 
584 
579 
584 


589 


1 ni , 
é fe ; 
‘ " \ 
r % . ‘ 
* 
‘ 
‘ i 
. 
a 
ty s ¥ 
: 4 
a - 
. 
, c- 
. 
J ‘ 
rr - ’ i 
‘ ‘ 
® 
| ‘ 
\ 
i i i 
. = 
ta yr 
ae 
2 ‘ 
Ps 
- ~ 
ery * 
- i 
- 4 
i 
’ bin < 
; 7 < 
e ‘ j ; me 
i 
: ‘ i 
| ‘ : ? 
} f ‘% 7 l 
i : ; t ; uy 
c . i wry 


7 Ae 


- ows! 
ars m") 


< 


— 


! : 
ya 


pit ats " 


a 


male 
, nD ; 


| ah 


Figs. 1, 2: 
Figs.-3, 4,8. 
Riss. (5,0,°7. 
Pigiio: 

Figs. 10, 11. 


Pigs 12. 


Pig ata. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


BXPEANATION, OF PLATE MEL 


LITTroRIDINA CHARRUANA (d’Orb.) . : 
LitToRIDINA AUSTRALIS (d’Orb-). Montevideo 

< ss . Bahia Blanca . 
LITTORIDINA BERTONIANA Pils. Face of type. 


POTAMOPYRGUS SCOTTI . Ts twio Coty pes : 
POTAMOPYRGUS PETININGENSIS (Gld.). Topotype from the orig- 
inal lot 


Lirroripina pictuM (d’Orb.) . 


Figs. 14, 14a. IDIopyRGUS SOULEYETIANUS Pils. Profile and face of the type. 


(VOL. 111) 


PAGE 


558 
557 
557 
559 
563 


563 
558 
565 


~ 


( 
X 


PATAGONIAN EXPEDITIONS \ 


ra. a 7 aay 


> 


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MWA he # {aig Hy 12 ee TS Or £ 
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«> ee ‘ : Ua i j hl ¢ ‘s 
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an far = eit) : 
* 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION: OF, PLATE XE. 


5 ii IW WED 


gs. 7, 72, 8. 


OO: 
Saris Ta, eee: 


RapIopDIscus PATAGONICuS (Suter). On the Rio Chico, 
50 miles above the Sierra Oveja 
SUCCINEA BURMEISTERI Doering. Rio Ghice 50 ‘giles 
above the Sierra Oveja 
<s S Doering. Seven miles above 
the Sierra Ventana 
LiTTORIDINA HATCHER! Pils. 
LitrorRIDINA SIMPLEX Pils. Cotypes . 
LitrorIDINA HATCHERI Pils. 40 miles above Siac 
Oveja 


(VOL. III) 


PAGE 
527 
520 
520 
553 
Do) 


555 


PATAGONIAN EXPEDI 


TIONS 


s 
7 


= 
aa 
=" 
= 
= 
ne 
e 
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Figs. 


Figs 


Figs 


Figs. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PEATE SXLilT. 


I, ta, 16, 2, 3, 4. CHILINA sMiTHI Pils. Cotypes. 5 
545,165. 7.. CHILINA FULGURATA LIvIDA Pils. Cotypes. 
O30, sO: Curiina smitui Pils. Immature specimens 
II, 12, 13,14, 15. CHILINA FULGURATA Pils. Cotypes . 


(VOL. 111) 


PAGE 
539 
539 
536 
B37 


m 


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Figs. 1; 12, 2, 


Figs. 3, 3a. 
Figce4. 
Figs. 5, 52. 


Figs. 6, 6a. 


Pigs. 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLIILA. 


2a. CHILINA CAMPYLAXIS Pils. 
CHILINA HATCHERI “ 
CHILINA FULGURATA “ 
CHILINA ANDICOLA “ 


CHILINA FULGURATA “ 


a3 “ce ae 


Cotypes. 

‘ype —.. 

Profile of one 

Front and profile views ai the 
type): 

Form from 25 rites abo the 
Sierra Oveja. 

Sculpture of last whorl Beton 
the suture, specimen from 
30 miles above the Sierra 
Oveja. 


(VOL. II) 


PAGE 
541 
540 
537 
540 


538 


538 


PATAGONIAN EXPEDITIONS VOL 


Helen Winchester del et pinxt 


JHILINA. 


ae iS 

Fi ~~ ‘| 

oe - say < a 

fee © oY sare . 

r@ hw! a ¥ 
mARS > 

iv ov! 


i , 
i a _ ; 
> pees e ; 
Meivisl Wren ; 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLIV. 


: £6, 7, 10: CHILINA FULGURATA LivipA Pils. Five miles 
above the Sierra Oveja ; 

PIS 18a, 20, 21) 22oo7. « FULGURATA OLIGOPTYx Pils. Cotypes. 

Be Ae ««  rutcurRaTA Pils.(?) Twenty-five miles 
above the Sierra Oveja. 

524, 242, 2400255 26 CHILINA STREBELI Pils. Cotypes . 

27, 28: se « so 8s 3 

120; 30, 304. CuHILtna PILULA Pils. Cotypes. 


(VoL. 11) 


PAGE 


539 
538 


538 
534 
534 
542 


Take 
AA « 


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y 


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if 


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wis ik‘ e, 


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é 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLV. 


Figs. 31, 32, 33, 34. Cuitina rusut Pils. Cotypes 


Figs. 35-39. 


Figs. 40-44. 
Fig. 45. 


CHILINA FLUMINEA (Maton), San Gabriel’s Island, 


opposite Colonia, Uruguay. 


a FLUMINEA MICRODON Pils. 
CuILina GLoposa Ffld. La Plata 


(VOL. 111) 


Cotypes. 


PAGE 


547 


544 
545 
546 


42 


. 


ai ; 7 : - i ° 7) 
CRE AAT. ADARS 
! : ied 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLVI. 


Figs. 1, 2, 4, 6. LyMN&A DIAPHANA INELEGANS n. subsp. Spring on the Rio 


PAGE 


Chico, 25 miles above Sierra Oveja_ . 527 

Figs. 357; 9. King. Spring on the Rio Chico, fifteen 
miles above the Sierra Oveja_. : 525 

Bigegs. : « INELEGANS. Stream 35 miles above the 
Sierra Oveja : ; ; : BOF 

Fig. 8. Lymna viaTor d’Orbigny. Pool on the bank of the Rio 
Chico de la Santa Cruz, a mile west of the Sierra Oveja . 525 

igs. 0, 11. LYMN4&A PATAGONICA RIOCHICOENSIS n. subsp. Rio Chico, 2 

miles below the confluence of the R. Belgrano . 528 


(vou 11) 


Figsial, 2553 
Figs. 4, 4a. 
Figs. 5, 5a. 
Pigs. 6,772: 
Fig. 8. 

Riss 9, 


PATAGONIAN EXPEDITIONS: 


EXPLANATION-OR- PEALE 2a NVI 


PAGE 


LYMN4&A DIAPHANA INELEGANS Pils. Form from Swan Lake . 528 
Lymnaa anpEANA Pils. Type. Near base of the Andes. 530 
LiTToRIDINA SUBLINEATA Pils. Type . : : : : 556 
MuscuLium ARGENTINUM (Orb.) Montevideo. : : : 605-2 
Muscutium pataconicum Pils. Type . : 3 : : 604 ios 
PIsIDIUM PATAGONICUM ZONIFER Pils. Type. . 3 : : 608 ; 


- (VOL 111) 


PLATE XLVLA 


PATAGONIAN EXPEDITIONS VOL II 


Helen Winchester del et pinxt 


LYMNZ@A, LITTORIDINA, Muscu.iuM, Pisipium, 


“ay ty, 


Lit) 


- 


= 


PATAGONIAN EXPEDITIONS: ZOOLOGY. 


EXPLANATION OF PLATE XLVII 


Figs. 1, 2, 3, 4, 5. Muscuttum paTAGoNicuM n. sp. Rio Chico, twenty-five 
miles above the Sierra Oveja 


Figs. 6, 6a, 7. cs ce Rio Chico, thirty-five miles above 
the Sierra Oveja . 
Figs. 8, 9. 10. PIsIDIUM PATAGONICUM n. sp. Spring on the Rio Chics 


fifteen miles above the Sierra Oveja 
Pigs 1n2, 13,14. PISIDIUM MAGELLANICUM Dall. Sixty-five miles north of the 
Rio Chico, in a spring near the 
base of the Andes . 
Figs. 15, 16. a S Dall. Spring on the Rio Ghee 
fifteen miles above the Sierra 
Oveja . 


(VoL. 111) 


PAGE 
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