126 THE NAUTILUS. 
Polygyra sayi Binn. Woodland. 
Polygyra monodon Say. Woodland. 
Strobilops labyrinthica Say. 
Pupa pentodon Say. Woodland. 
Vertigo gouldi Binn. Woodland. 
Ferussacia lubrica Mull. 
Succinea obliqua Say. Woodland. : 
Succinea ovalis Gld. Aroostook Co., Me. 
Carychium exiguum Say. Generally diffused. 
Limneea humilis Say. 
Limnzea desidiosa Say. 
Limnea emarginata Say. 
Limneza emarginata mighelsi W. G. B. 
Planorbis trivolvis Say. 
Planorbis bicarinatus Say. 
Planorbis bicarinatus aroostookensis Pils. 
Planorbis campanulatus Say. 
Planorbis deflectus Say. Streams generally. Very large speci- 
mens in inlet of Cross Lake. 
Physa ancillaria Say. Square Lake. 
Physa heterostropha Say. Generally abundant. 
Campeloma decisum Say. Lakes and Streams. 
Pomatiopsis cincinnatiensis Lea. Caribou Lake. 
Unio complanatus Sol. Lakes generally. Some are very large. 
Margaritana margaritifera L. Aroostook R. (rocky bottom). 
Margaritana undulata Say. Square Lake. 
Anodonta fragilis Lam. Caribou L. (mud bottom). 
Spherium suleatum Lam. Salmon Brook Lake. 
Spherium striatium Lam. Square Lake. 
Pisidium variabile Prime. Caribou Lake. 
Pisidium abditum Hald. Caribou Lake. 
NEW SPECIES OF LAND-SHELLS FROM THE GALAPAGOS ISLANDS. 
BY WILLIAM H. DALL. 
Bulimulus (Nesiotus) Reibischii n. s. 
Shell elevated, slender, of a pale ferruginous tint, rather solid, 
with nine whorls; apex funiculate as in other Nesiotes, the first 
two (nepionic) whorls finely ribbed and polished, the remainder 
with numerous oblique or irregular transverse ribs crossed by nu- 
