FAMILY SPH^ERIID^E 1 43 



* Corneocyclas abyssorum Stimpson. 



Pisidium (sp.) Smith and Verrill, Am. Journ. Sci., II, p. 448, Dec, 1871. 

 Pisidium abyssomus (Stm.) Hoy, Trans. Wisconsin Acad. Sci., 1, p. 100, 



1872 (err. typ.). 

 Pisidium abditum var. abyssorum Stimpson, S. I. Smith in Rep. U. S. Fish 



Com. for 1872-3, p. 704, 1874. 

 Pisidium abyssorum Sterki, Nautilus, XI, p. 124, March, 1898. 



Range. — Deep water of the Great Lakes, and of the lake region 

 of northern Michigan and Minnesota. 



Lake Michigan; Lake Superior to a depth of 159 fathoms (food 

 of Coregonus) ; Pine Lake, Mich. ; Green Lake, Wisconsin. 



This is another of the extra-limital species which 

 search will probably reveal in Lake Winnipeg and other 

 northern lakes. 



Corneocyclas ventricosa Prime. 



Pisidium ventricosum Prime, Proc. Boston Soc. Nat. Hist., 



iv, p. 68, 185 1 ; Mon. Am. Corbie, p. 72, figs. 79, 80, _, - 



',f v y Fig. 116. 



1865. 



Corneocyclas 



Range. — Massachusetts, Canada, and northward to ventricosa. 

 Great Slave Lake. 



Corneocyclas rotundata Prime. 



Pisidium rotundatum Prime, Proc. Boston Soc. Nat. Hist., iv, p 

 164, 185 1 ; Mon. Am. Corbie, p. 72, figs. 81, 82, 1865. 



Range. — Lake Superior region; Manitoba; St. Paul Fig. 117. 

 Island, Bering Sea ! Comeocy- 



Corneocyclas steenbuchii Moller. . a , . 



J tundata. 



Cyclas steenbuchii Moller, Index Moll. Gronl., p. 20, 1842. 

 Pisidium steenbuchii M6RCH, Am. Journ. Conch., IV, p. 37, 1868 ; ibid., 

 Rink's Greenland, App., p. 440, 1877. 



Range. — Greenland, on the west coast! Iceland! Ungava, Lab- 

 rador. 



This species appears to be unfigured, but there are specimens in 

 the Jeffreys collection from Iceland as well as Greenland. It appears 

 to belong to the section Cyclocalyx. 



Corneocyclas occidentals Newcomb. 



Pisidium occidentale Newcomb, Proc. Calif. Acad. Sci., 11, p. 94, 1863. — 

 Prime, Mon. Am. Corbie, p. 73, 1865. 



Range. — California to British Columbia. 



East slope of Sierra Nevada, in California, to"o„7oo feet. Nanaimo, 

 Vancouver Island, British Columbia ; Spokane Falls, Wash. 



