164 DISTRIBUTION OF PUPILLIDAE. 



with an Antillean fauna). Microcerion (vol. 26, p. 151) from 

 the same formation, is, in my opinion, a specialized tangent 

 from Microstele, with which it agrees in all essential char- 

 acters. The question arises, whether Gastrocopta s. str., 

 Pupoides and Microcerion are traceable to Africa, over a 

 translantic bridge which is believed to have existed in the 

 Mesozoic and possibly later,^ or whether they formed an 

 early migration by the northern route. 



United States northward; Lower California. 



Chaenaxis tuba P. & F. 24:2. Arizona. 

 C. intuscostata Clapp. 24:3. Arizona. 

 C. i. brevicostata Pils. 24 :4. Arizona. 



Gastrocopta rupicola Say. 24 :58. Southeastern U. S. 



G. r. matacumbensis Pils. 24 :6. Florida Keys, 



G. procera Gld. 24 :62. Eastern. 



G. p. sterkiana Pils. 25 :357 ; 27 :207. S. Dakota to Texas. 



duplicata Sterki. 24 :65. 

 G. p. mcclungi H. & J. 24 :66. S. Dakota south. 

 G. cristata Pils. & Van. 24 :68. Texas to Arizona. 

 G. riograndensis Sterki. 24 :69. Texas. 

 G. pellucida Pf r. 24 :75. Southern States. 

 G. p. hordeacella Pils. 24 :78 ; 28 :117. Southern States. 

 G. p. parvidens Sterki. 24 :80, 27 :207. Arizona. 

 G. quadridens Pils. 24 :57. Arizona, N. M. 

 G. (Albinula) armifera Say. 24:15. Eastern States. 

 G. (A.) a. similis Sterki. 24:17. 

 G. (A.) a. affinis Sterki. 24:18. 

 G. (A.) a. abbreviata Sterki. 24:18. 

 G. (A.) a. ruidosensis Ckll. 24:19. New Mexico. 

 G. (A.) a. clappi Sterki. 24:20. 



G. (A.) contracta Say. 24:22. Eastern U. S. and Mexico. 

 G. (A.) c. peninsularis Pils. 24:24. Florida. 

 G. (A.) c. climeana Van. 24:24. Southern States. 

 G. (A.) holzingeri Sterki. 24:25. Eastern States. 

 G. (A.) h. agna P. & V. 24 :26. Kansas. 

 G. (Vertigopsis) pentodon Say. 24:28. Eastern States. 

 G. (V.) p. gracilis Sterki. 24:31. 

 G. (V.) tappaniana C. B. Ad. 24:33. Eastern States. 

 G. (V.) carnegiei Sterki. 24:35. Ohio. 



1 CA Schuchert, "Gondwana Land Bridges", Bull. Geol. Soc. of 

 America, vol. 43, p. 875. 1932. 



