HELICIGONA. 309 



and to compare it with Campy Icea ; but strangely enough he does 

 not alter the current classification of the species. The resemblance 

 of H. personata to the American Triodopsis is merely a case of 

 incomplete parallelism. The two groups are readily separated by 

 observing the form of the parietal barrier. Dr. H. von Ihering has 

 -ably discussed the relationships of H. personata, ranking it, of 

 course, in Campy Icea. 



H. personata Drap., iii, 147. H. subpersonata Midd., iii, 147. 



isognomostomos Gin. pt. 

 v. debilis West. 



Subgenus TROPIDOMPHALUS Pilsbry, 1894. 



Shell with the general characters of Chilostoma, but subangular 

 around the umbilicus, and quincuncially punctate or papillate (as 

 in some members of the H. planospira group). Type H. lepidotri- 

 tha A. Braun, pi. 71, figs. 59, 60. 



The lower Miocene forms for which this section is proposed have 

 the verge of the umbilicus subangular as in most (but not all) 

 Chloritis (con/, p. 118) and many species of Eulota; and in fact 

 the group may belong to Eulota rather than to Helicigona. At all 

 events, the closest resemblance is traceable between H. lepidotricha 

 and certain southeast Asian Eulotas. On theoretical grounds, how- 

 ever, I am disposed to believe that Eulota has no extensive past 

 history in Europe, being a recent straggler from East Asia ; and 

 this is supported in the main by palseontological evidence. 



A thorough study of the Miocene Helices is necesssary to deter- 

 mine whether the peculiar sculpture which occurs in so many forms, 

 is a character assumed simultaneously by many subgenera and 

 genera, or an indication of actual genetic relationship. Not much 

 evidence can be adduced in favor of the latter view from the recent 

 fauna, for species of widely different genera exhibit the hairs or 

 papillae arranged in obliquely decussating series : In HYGROMIA, 

 H. consona, lanuginosa, etc.; in HELICIGONA, hairy members of the 

 planospira group ; in THYSANOPHORA, T. stigmatica and its allies ; 

 in EULOTA, numerous oriental species. The list could be indefi- 

 nitely increased. It will be perceived from this that those authors 

 who insist upon the presence of Chloritis in the European Miocene 

 fauna, stand upon narrow and insecure footing. 



H. robusta and trichophora Reuss., from the lower Miocene of 

 Tuchoric, evidently belong to this group. 



