O^ORINIA. 1 7 



nate, stripes of white and brown; margin of umbilicus crenu- 

 lated, umbilical wall with a crenulated, medial rib. 



Diam. 10-17 mill. 



Red Sea; Indian 0.; Pacific 0. 



T. gyra, iMeusch. ; T. areola, Gmel. ; T. perspectiuiuncula, 

 Dillwyn, and T. tesselata^ Desh., are synonyms. 



Yar. DEPRESSA, Phil. PI. 5, figs. 78, 79. 



Shell very depressed ; color white with radiating brown 

 streaks, interrupted white bands on the strong ribs about the 

 periphery, umbilical crenulations and surrounding portion of 

 the base white. 



Var. PLAisfULATA, Hanley. PI. 5, fig. 77. 



Shell ver}^ depressed ; color brownish, with interrupted white 

 bands above the suture and on the two strong ribs about the 

 periphery. 



In the American Journal of Concholog}' (vol. v, p. 81, 18G9), 

 W. H. Pease states that the operculum of T. vaiHegata from the 

 West Coast of America, differs widely- from that of the same 

 species from Hawaii and the East Indies. He thus describes it : 

 " It is composed of plates disposed in the shape of a screw, of 

 three whorls. The plates are wide apart, and furnished on their 

 edges with short, stout bristles and the sides reticulated with 

 raised strias " (PL 1, fig. 14-16). I have examined specimens of 

 the West Coast species, kindly loaned by Dr. Robert E. C. 

 Stearns, of tjie United States National Museum, and am unable 

 to verify Mr. Pease's statement, the opercula being normal. 



T. DORSUOSA, Hinds. PI. 5, figs. 80, 81. 



Shell depressed ; whorls longitudinally striated, spirally sul- 

 cate and ten-ribbed, the rib on the periphery and that below it 

 being strongest ; color reddish brown, confusedly blotched with 

 white, the two stout ribs about the periphery with interrupted 

 white bands; umbilicus moderate, crenulated, umbilical wall 

 with a spiral medial rib. Diam. lo mill. 



Pacific Islands. 

 T. CYLTNDRICA, Gmeliu. PI. 5, fig. 82. 



Shell conic, elevated ; whorls longitudinally striated, spirally 

 sulcate and ten-ribbed, the three ribs about the periphery being 

 strongest; color chestnut-brown, sparingly mottled with white 

 2 



