128 THE NAUTILUS. 



are similar to the Canadian examples, which he refers to that spe- 

 cies. 



Carychium exiguum Say. 

 Limnoea stagnalis L. 

 Limnfea catascopium Say. 



Two forms of this species are represented in the collection. One 

 from the Saginaw River is of the usual form, but of unusual size, 

 one example being nearly one and one-fourth inches in length. 



The other form from Saginaw Bay is characterized by its greatly 

 inflated body whorl and very short, rapidly acuminating spire. A 

 single specimen from Lake Huron represents the form usually found 

 in the Great Lakes. 



Limnsea reflexa Say. Bayou, East Sagiuaw and Saginaw Bay. 

 The latter somewhat smaller and more slender than the former. 

 Limnsea reflexa scalaris. Intermediate between the type and the 

 variety. 



Limnaea palustris Mull. Larger than the average in size. The 

 striped variety corresponding to form of L. reflexa known as zebra 

 Tryon, is also represented. 

 Limnaa cubensis Pfr. 

 Physa ancillaria Say. Saginaw Bay. 

 Physa sayii Tapp. 

 Physa gyrina hildrethiana Lea. 

 A])lexa hypnorum L. 

 Planorbis trivolvis Say. 

 Planorbis bicarinatus Say. 

 Planorbis campanulatus Say. 

 Planorbis albus Mull. 

 Planorbis exacutus Say. 



Planorbis parvus Say. Among a number of the usual form of this 

 species occurs one of the curiously distorted examples, in which the 

 whorls almost from the apex are entirely detached from each other 

 and coiled obliquely like a ram's horn. 

 Segnientina armigera Say. 

 Ancylus fuscus Ad. Saginaw River. 



Ancylus parallelus Hald. Saginaw River. Much narrower and 

 with the sides more flattened and hence more nearly parallel than 

 in specimens from other localities. 



Lyogyrus pupoidea Gld. Heretofore this species has been cited 

 only from the western part of the State. 



