STROBILOPS, S. G. ENTEROPLAX. 51 



rounded edge is set with many low microscopic teeth pointing 

 towards the aperture, sometimes subobsolete, but evenly dis- 

 tributed, not gathered upon nodes as they are in typical Stro- 

 bilops. This is also a character of Discostrohilops, which on 

 the whole seems to be the most nearly related group. No 

 closely related fossil species have been found, and as Wenz 

 remarks, they are hardly to be expected. The group may very 

 likely have been evolved locally in its present area. All the 

 known species are quite thin shells having a delicate peripheral 

 carina over which the riblets of the upper surface do not pass. 

 These forms were first found by Dr. 0. von Moellendorff 

 when on a collecting trip in Cebu in company with 0, Koch, 

 a compatriot settled there and working up the butterfly fauna. 

 They ascended Mt. Licos, estimated to reach a height of about 

 500 meters, a peak circled by precipitous crags and a girdle 

 of high forest springing from a slope strewn with great blocks 

 of rock and rubble. Here in clefts and crevices of the rocks, 

 often reached by standing insecurely on the shoulders of his 

 guide, von Moellendorff found the Enteroplaces, Aulacospiras 

 and many other new snails. "None of my finds," he writes, 

 "have given me such joy as this one and the following {S. 

 polyptychia and trochospira) , secured almost at the peril of 

 my life." 



Key to Species of the Philippine Islands. 



1. Form subdiscoidal, with weakly convex spire and a series 



of about 10 short basal folds. Cebu. 



8. polyptychia, No. 16. 

 Form low-trochoidal ; fewer basal folds (2). 



2. Four or five basal folds (3). 



Three basal folds ; diam. 3.4 to 3.7 mm. Northern Luzon. 



8. quadrasi, No. 19. 



3. Diam. 4 mm. ; a low interparietal lamella extending inward 



beyond the two parietals. Cebu. ;S^. trochospira, No. 17. 

 Diam. 3.2 to 3.7 mm. ; a low radial callus extending across 

 the wall at the inner end of the two parietals. Bohol. 



8. hoholensis, No, 18. 



