PERUVIAN REGION: dis 
others dry, rocky and rainless, especially in the south; it is 
watered by numerous streams—the affluents of the Amazon and 
Plata. The hydrogravhical areas of these two great rivers have 
been represented on the map, but the southern boundary of the 
Brazilian Province extends beyond the line of watershed to 
the tropic, including the head-waters of the Piata, in which the 
same remarkable fresh-water bivalves are found as in the 
Bolivian streams. (D’Orbigny). The mountains around the 
Lake Titicaca are the highest in the New World, and there 
M. D’Orbigny found severai species of Helix up to the elevation 
of 14,000 feet; Bulimus Tupaici ranges to 9,000 feet. The large 
and typical species of Bulimus belong to this proyince; B. ovatus 
and oblongus are found near the coast (p. 291), and B. maximus 
farther inland. The auriculoid Bulimi (Otostomus, and Pachy- 
otis, Beck), those with an angular mouth (Goniostomus, Beck), 
and the pupiform species, with a toothed aperture, (Odonto- 
stomus), are characteristic of this region, and also some of the 
most elongated forms (Obeliscus). The lamp snails (Anastoma) 
and Megaspira, genera inhabiting France during the Eocene 
period, are now peculiar to Brazil; Simpulopsis is also peculiar, 
and Streptaxis attains its maximum there. The Cyclostomidce are 
few, and the other West Indian forms have almost disappeared. 
HEVCLIRG cacisesses'ccossse wee AT Glandinas ie. sssscaseses 1 Cyclophorus ......... Hoa | ey 
SELGDEARIN) vesascvesvsress 11 Tornatellina...... noooop| lt Cyclotus ....006 copnoog A 
ANASTOMA ..c.escecerees 7 WVitrIN Afeseesccrcseecosenes 5 Cistulaeesastsccctere soce UL 
SINUS tres asessescasees 250 OmalonyX.....sseceeee ag il Helicina ......0...000e . 12 
MeGaspira.....sccecevere 2 Simpulopsis ..... con & 
The land slugs are Peltella palliolum, Vaginulus solea, and 
Limax andicolus. The fresh-waters of the interior are rich in 
bivalves of pecular genera :*— 
IVAN erseiseyvixcccsacees il Ampullaria ........+0 2 (WI) cecgeengdocnadnooocr 4 
PUIG VLU seve sc cece aeses 1 Corbicula .....cseeseeees 2 IGBKOHWOE) © Aecocasccocasodiine 1 
EISMON DIS scsccccecavevee 4 PEISIOUITMG seeressseatmtes 1 FLYTIA ....0s00000. acc00nc0 1 
Paludestrina..........+. 2 ANIOM OMe senssssssece ses 1 Castalia ....cccccvere no 
INEATIR Ri cnstvesesceseeeeus 1 Monocondylza......... i Mycetopus ....ceeee 9 
SUCCINEA ....scsesseores 27 
24, PERUVIAN REGION. 
The long and narrow tract between the Andes and Pacific, 
extending from the equator to 25° S. lat. forms a distinct, 
though comparatively unproductive province, including the coast 
of Ecuador, Peru, and Bolivia. It is warm and almost rainless ; 
* The American Expedition explored forty Brazilian streams, and found only one 
Ampullaria, one Mclunia, and one Pianorbis. (Gould.) 
