HYPSELOSTOMA. 179 



strongly bilobed crest. The upper palatal plica is also bilobed, 

 and with the augiilo-parietal forms an oval sinulus. The 

 other lamellae and plicas are deeply placed. Lower palatal 

 and columellar large, basal fold smaller. A very deeply im- 

 mersed, short infraparietal lamella is often developed, and 

 usually a short interpalatal plica; so that there may be as 

 many as 7 or as few as 5 teeth. In H. roebeleni the angulo- 

 parietal lamella is less distinctly bilobed, the upper palatal 

 plica is short and simple, and interpalatal, basal and infra- 

 parietal teeth are absent. H. mirabile also seems to have 

 fewer teeth. The usual diameter of H. tubiferum is 4.3 to 4.4 

 mm. The length of the neck varies. 



When cleaned with sufficient care (and not too much), deli- 

 cate spiral strias may be seen in places on the second and third 

 whorls, but they are easily removed. The embryonic shell 

 comprises iy 2 whorls, and is minutely granulose. 



"In some places hundreds may be found adhering in dry 

 weather to the surface of limestone rock, upon which alone it 

 appears to occur, in the same manner as species of Pupa and 

 Clausilia are frequently found in Europe. The animal of H. 

 tubiferum is very small and black, of the usual helicidous 

 form, with 4 tentacles" (Stanford). 



"The specimens I saw were pale gray; they had the eye 

 pedicels rather more elongated than usually in species of 

 Pupa, and more resembling those of Helix; the tentacles at 

 the base of the rostrum were very minute, both blackish. The 

 rostrum itself is thick and very minutely notched at the front 

 edge. The foot is short, ovately elongated, roundly truncate 

 posteriorly. The animal, when moving, carries its shell in a 

 reverse position" (Stoliczka). 



2. HYPSELOSTOMA MIRABILE (J. Mabille). PL 31, figs. 6, 7. 



Shell very small, broadly umbilicate, subdepressed-convexly- 

 discoidal, rather solid, scarcely shining, white, roughly stri- 

 atulate under a strong lens. Spire convex ; apex large, mamil- 

 late, corneous, glossy. Whorls 4, convex, gradually and reg- 

 ularly increasing, separated by a simple, impressed suture, 

 the last whorl large, nearly equal in width to the penultimate 



