THE NAUTILUS. 13 



shells. The surface is usually destitute of spiral sculpture, 

 only a few faint impressions being observable in rare specimens. 

 One individual, however, had been injured when the body 

 whorl was about half completed and the part of the shell suc- 

 ceeding the injured portion is very heavily impressed with spiral 

 lines, while the rest of the shell is perfectly smooth. 



This shell was first recorded from Tomahawk Lake, Wis- 

 consin, as Physa ancillaria warreniana. The same form occurs 

 in Lake Maxinkuckee, Indiana, on the shore of Lake Michigan 

 at Chicago, and a somewhat similar form has been received 

 from Georgian Bay, Canada. It is the most abundant mollusk 

 in Oneida Lake where it occurs on a wave-beaten shore. It is 

 probably widely distributed, and will be found in collections 

 labeled ancillaria and heterostropha. Specimens that have sur- 

 vived a second year and are of large size compare favorably with 

 warreniana but may at once be separated by the absence of spiral 

 sculpture which is especially strong in shells of Lea's species 

 from South Dakota and other western states. 



The bibliography of the new species is as follows: 

 1902. Physa heterostropha Baker (non Say). Moll. Chicago 

 Area, Part II, p. 308, pi. 34, fig. 2 (part). Lake 

 Michigan. 



1911. Physa ancillaria warreniana Baker (non Lea). Trans. 

 Wis. Acad. Arts, Sci. and Letters, XVII, p. 234. Tom- 

 ahawk Lake, Wis. 

 1916. Physa ancillaria warreniana. NAUTILUS, XXX, p. 8. 



Oneida Lake, N. Y. 



1916. Physa ancillaria warreniana. Tech. Pub., N. Y. State 

 Coll. For., Syracuse Univ., No. 4, p. 273, etseq., Fig. 

 45, nos. 34, 35. Oneida Lake. 

 1918. Physa warreniana. NAUTILUS, XXXI, p. 89. Oneida 



Lake. 



1918. Physa warreniana. Tech. Pub., N. Y. State Coll. For- 

 estry, No. 9, p. 173, et seq. Oneida Lake. 



