SONNINIA— CLASSIFICATION. 387 



A. These characters are well marked. 



a. Costaa irregular. 

 Sonn. abnormis. (Pages 377 and 404.) 



]3. Costaa regular. 

 1. Correlated umbilication considerable. 



Sonn. euromphalica. (Pages 362 and 405.) 

 Sonn. omphalica. (Pages 363 and 405.) 



2. Correlated umbilication not so considerable, and ornament rather less. 



Sonn. spinicostata. (Pages 337 and 405.) 

 Sonn. spinea. (Page 405.) 

 Sonn. submarginata. (Pages 329 and 406.) 

 Sonn. substrjata. (Pages 330 and 406.) 



B. L scarcely so short and broad-stemmed. 



Sonn. nodata. (Pages 369 and 407.) 

 Sonn. marginata. (Pages 321 and 407.) 

 Sonn. paucinodata. (Pages 370 and 408.) 

 Sonn. attrita. (Pages 371 and 408.) 



B. The lobes are fairly long. 

 A. The lobes are rather wide-stemmed. 



FlG. 13. — Outline of L of Sonn. dominata. 



Sonn. dominata. (Page 408.) 

 Sonn. contusa. (Page 409.) 



B. TJie lobes are narrow -stemmed. 



a. The lateral lobules decidedly anisometric. 



1. The outer lobule about as large as the terminal lobule. 



\1 

 Fig. 14. — Outline of L of Sonn. dominica. 



