106 TEIXOSTOMA. 



T. COSTULATUM, Folin. PI. 35, fig. 75. 



Deeply umbilicated, depressed, disk-like, very slightly convex 

 above, subplanate below, vitreous, whitish, longitudinally minutely 

 costulate, above the base these are decussated by a spiral thread ; 

 whorls 3, rapidly increasing, base with cord below the periphery : 

 aperture oblique, subcordiform, margins subacute, joined by an 

 oblique channel above the penultimate whorl. Diam. 2 mill. 



Cape Sta. Anne, W. Africa. 



Subgenus LEUCORHYNCHIA, Crosse, 1867. 

 T. ( 'ALEDONICUM, Crosse. PI. 35, figs. 85, 86. 



Subdiscoidal, slightly convex above and below, polished, shining, 

 whitish; whorls 3, flattened, rapidly increasing, periphery carinate; 

 peristome continuous, simple, thickened at the base and produced 

 into a tongue-like callus past the umbilicus, leaving a perforation 

 between it and the columellar wall. Diam. 3 mill. 



New Caledonia. 

 T. CROSSEI, Tryon. PL 35, figs. 86a, 866. 



Differs from the above in having a rounded periphery ; surface 

 polished, without a trace of striae. Diam. 3 mill. 



Singapore, (Archer) . 



Subgenus MICROTHECA, A. Ad. 1863. 



T. CRENELLIFERUM, A. Ad. PI. 35, figs. 76, 77. 



Thick, globose, broadly umbilicated, longitudinally, somewhat 

 obliquely plicate, whorls crenulated at the channeled suture, umbuli- 

 cus with a crenulated marginal angle, peristome thick. 



Diam. 3'5 mill. Japan. 



Subgenus MORCHIA, A. Adams, 1860. 

 T. OBVOLUTA, A. Ad. PI. 35, figs. 78, 79. 



Obliquely ovate, laterally compressed, last whorl angular above 

 and below, the spire depressed, umbilicus wide, its margin suban- 

 gulate, aperture obliquely ovate, peristome thick, continuous. 



Diam. 3'5 mill. 



Japan. 

 T. MORELETI, Fischer. PI. 35, figs. 80-82. 



Depressed, whitish, whorls 4, the first ones obliquely immersed, 

 the last embracing, obliquely flattened with a tuberculate-crenate 



