pupillidae and related groups. 191 



Review of the anatomy op Pupillidae and related groups. 



By H. Burrington Baker. 



The systematic inferences from these few notes on anatomy 

 are aired with many misgivings ; any deductions based on the 

 animal alone would be weak and this would be especially true 

 of a group in which the shell characters, so far as my slight 

 knowledge goes, appear manifest while those of the soft parts 

 are difficult to study and still more so to evaluate. Personally, 

 I am more inclined towards "Watson's (1920) broad limits of 

 the Pupillidae than towards the other extreme proposed by 

 Steenberg in his exquisitely careful ''fitudes" (1925) ; to me, 

 the total range of anatomical differentiation seems much less 

 than in most families of pulmonates. Incidentally, the male 

 genitalia of these Orthurethra go through strikingly parallel 

 modifications to those in the sigmurethrous Sagdidae (which 

 I happened to study simultaneously, like Steenberg the Clausi- 

 liidae) ; in these, the appendicular arm functions as the apex 

 of the penis. Finally, one must not forget that the soft parts 

 of a large majority of the species and even of the genera and 

 subgenera are still unknown. A tentative outline of the rela- 

 tionships between the subfamilies may be expressed in the 

 form of a key, with many derivative conditions omitted, as 

 follows : 



A. Valloniinae ( ?) ; shell more heliciform, without teeth 

 [unless Strohilops (p. 2) or Spelaeodiscus (vol. 27, p. 180) 

 be included] ; radula with fundamentally bicuspid laterals 

 and marginals but last with ectoconal accessories; penis 

 (when present) well differentiated. 



1. Penis bifid and sharply separated from its epiphallus 

 and appendix ; prostate and spermatheca short. 

 a. Shell dominantly calcareous and with more or less 



thickened and expanded peristome Valloniinae. 



6. Shell dominantly epidermal, often with membranous 



excrescences; peristome usually thin 



Acanthinulinae. 



