64 COCKERELL : MOLLUSCAN FAUNA OF COLORADO. 



is yet known from the Arkansas division, while the only 

 bivalves are Pisidium variabile Prime and P. pusilbim 

 Gmel. from Custer Co., the latter going up to above 

 ii,ooo feet altitude. 



Rio Grande. — Not much is known of the MoUusca of this 

 district. In Hinsdale Co. Ingersoll reports Planorbis 

 plexatus Ing. and P. parvus Say from St. Mary's Lake, 

 and a Limncea aff. rowellii Tryon was found in Rio 

 Grande Co., while I have found Agtiolimax 7nontanus 

 Ing., Vitrina pellucida Miill., Patula cronkheitei Newc, 

 Succinea avara Say, Physa heterostropha Say, and Pisi- 

 dium pusillu?n Gmel. in Saguache Co., and Ingersoll 

 reports a few species from the same county. 



San Juan.- — -Known only from IngersolFs records — Vitri?ia 

 pfeifferi, Hyalifia arborea, H. co?ispecta. Microphysa inger- 

 solli, Pupa alticola, Pupa '■'■ Calif ornica Rowell," Succinea 

 ^^ lineata Binn.," Lif?incza siagnalis, L. ferruginea, Physa 

 cooperi, &c. Mr. C. F. Ancey, who has examined Inger- 

 solFs specimens, informs me that the "S. lineata" are 

 mostly S. avara Say {S. lineata does, however, occur in 

 Colorado— Binney records it from Este's Park, in the 

 Platte division) and that the "Z'. califorjiica" belong to a 

 distinct species, which he proposes to call Pupa ingersolli 

 Ancey. Mr. H. A. Pilsbry had previously expressed to me 

 (in Hit.) his doubt whether IngersoU's Califortiica was 

 really that species. 



Dolores. — Records are at present entirely wanting. 



Grand. — The principal recorded species are Patula slrigosa, 

 Pupa marginata, Succinea 7iuttallia?ia, S. rusticana, 

 LimncBa desidiosa, and Physa wolfiana. I have found 

 Hyalina radiatula in Mesa and Garfield Cos., and var. 

 viridescenti-alba in Mesa Co. Conulus fulvus occurs in 



was found in a hot spring, at Saint, near Bigorre, Pyrenees, where it was 

 associated with Neriti7za thermalis Boubee. I am indebted to Mr. C. F. 

 Ancey for specimens of this interesting variety of P. acuta. 



J.C, vi., Jan., 1889. 



