WEST COAST PULMONATA. 19 



Mr, Binney writes that lie once found a similar colony of 

 Hyalina exigua in a fern garden in Boston. The resem- 

 blance of these two species externally is very great, but on 

 account of differences in jaw and teeth, the former is put 

 lately with the Helicidce. The similarity of habits now^ 

 shown, in addition to their similar shells, is a strong argu- 

 ment for retaining both in one group. Mr. Raymond has 

 also found it in a garden in Oakland. 



Helicodiscus lineatus Say. (No. 22.) 



In the "Manual of American Land-shells," Mr. Binney 

 puts this among the "universally distributed species," (a 

 division which might better be named circumboreal or 

 boreal for those only North American), since many are not 

 found far south of latitude 49°, or only along mountain 

 ranges. He remarks that the specimens found by Hemphill 

 at Oakland, Cal., and in Idaho, are without the colored 

 lines from which the species was named. In this they re- 

 semble the undescribed form (No. 23), but unlike that, 

 probably have internal teeth. This is a reason for deferring 

 the description or naming of the latter until living speci- 

 mens can be obtained. I have not heard of the former 

 having been obtained by anyone else in California. 



Helicoids. 



Mesodon (Aplodon) armigerUS Ancey. (No. 25.) 



The recent separation of this form from the Oregouian 

 31. Columbia nus, is fully elucidated in Binney 's 2d Supple- 

 ment, with illustrations. Considering, however, the occur- 

 rence of another variety in Plumas County (Bull. 7, 358), 

 and that no specimens from the northwestern part of Cali- 

 fornia have yet been compared with either of them, it seems 

 probable that all the later forms will yet be found to inter- 

 grade with that first described, reducing them to subspe- 

 cies. 



