58 THE NAUTILUS. 



Mr. Kennard tells me " that Children was the first Eng- 

 lishman to use ' ' Type " as we do now ' '. 



It follows, therefore, that this was the earliest designation, 

 of a type for Ancylus and forecloses any further discussion, 

 on that point. Acroloxus Beck and Velletia Gray conse- 

 quently fall into the synonymy of Ancylus. 



Incidentally I would call attention to the fact that Geoffrey, 

 to whom the genus Ancylus is usually credited, was not a 

 binomial writer and, therefore, can not be recognized (see 

 Ball, Harriman Alaska Expedition, XIII, 1905, p. 80, as to 

 Planorbis) . Ancylus should consequently be quoted as of 

 Miiller, 1774. 



But this leaves the position of fiuviatilis Mull, and its allies 

 still to be determined. As I have already shown (loc. cit.) 

 Ancylastrum Bgt. is not available and no other name has been 

 suggested, I would, therefore, propose Pseudancylus as the 

 generic name for the group with Ancylus fluviatilis Mull, as 

 the type. 



I am iinder great obligations to Dr. H. A. Pilsbry for the 

 data in regard to Children's paper. 



SOMETHING ABOUT ANGITREMA 



CALVIN GOODRICH 



In the Duck river at Centerville, Hickrnan co., Tenn., Dr. 

 A. E. Ortmami last summer collected nearly 200 specimens 

 of Lithasia (Angitrema) geniculata Hald., 1840, young and 

 adult. About one-third of the material was typical geniculata, 

 as it is known from the Cumberland river. The rest shaded 

 from these forms into Lithasia fuliginosa (Lea), 1841, by 

 scarcely perceptible gradations. 



Farther up the river at Columbia, Maury co., Dr. Ortmann 

 took a second lot of these mollusks. Here the form geniculata 

 was almost rare while fuliginosa was common. Yet examina- 

 tion showed them all to be of the same species. 



The collections of Dr. Ortmann in the Harpeth river were 

 equally as novel. At Belleview, Davidson co., Tenn., most 

 of the shells were of the form that appears in cabinets as 

 Angitrema duttondana (Lea), 1841. A single specimen was 



