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no Reprinted from the Revorts OF PRINCETON UNIVERSITY EXPEDITIONS TO PATAGONIA, 1896-1899, Vol. ILI. i
pra
leg &
& ; 5
-* }

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

>

5 ae °
wi :
7 ae

MWA he # {aig Hy 12 ee TS Or £
ay y wt 7 & 4
Pi

* - : 7
, a
. a ; ,
. * ~
by
Ore TAY (eae | ;
i - a
Th a . j ’
. : : au y wae Pf ‘i Si .
«> ee ‘ : Ua i j hl ¢ ‘s
~ ay . we
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
Oa

fe :

&

~

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

ee mri

sia aii Alger

nf:

a og a

a
ae ear?
we) iv
+ —_
4
|
. '>
ad
bd : af
w
4 , i
7 ”
A
7
-
at
eS
oe
‘a | i ;
iy 7
—
~ ay
‘ J 7
y
- ae
? . y
i}
5
a
_-
*
*-
‘
™es
TT |

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 «

~~ e
y

a
if

fluuye)

eA
1.
wis ik‘ e,

‘7

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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