TROOHUS. 35 



Conchyl. Cab. II, p. 44, t. 10, f. 15. T. sacellum REEVE, Conch. 

 Icon. f. 78, 93. T. sacellum var. /?, (or T. philippinarwn) FISCHER, 

 Coq. Viv., p. 412. 



( Var. B. periphery with acute spine-like nodes.) 

 Trochus sacellum PHILIPPI, Conchyl. Cab. II, p. 309, t. 44, f. 13. 



FISCHER Coq. Viv. p. 412. 



I quote Chemnitz merely because authors have referred to his 



figures. The first binomial name is that of Gmelin. 



T. ROTA, Dunker. PL 12, figs. 75-77. 



Shell conical, white or greenish, marbled or spotted irregularly 

 with red maculations ; whorls planulate, subgranose, encircled above 

 with two or three spiral series of tubercles, costate below, the folds 

 thick, suboblique, produced at the periphery into 17 to 18 obtuse 

 spines ; base concave, bearing 7 to 8 concentric subnodose lirse ; 

 false umbilicus deep, contorted; columella subnodose; basal lip 

 subserrate ; aperture rhomboidal, fauces sulcate. 



Alt. 20, diam. 25 mill. (Dunker.) 



Japan ; (Nagaski, Decima, Ooshima). 



T. rota DKR., Malak. Blatt., vi, p. 238, I860. Moll. Japonica, p. 

 21, t. 3, f. 4. LISCHKE, Jap. Meeres.- Conchyl., 1869, p. 94, t. 6, f. 

 20, 21. Polydonta gloriosum GOULD, Proc. Bost. Soc. Nat. Hist., 

 1861, p. 19. Otia, p. 158. 



This lovely species is closely allied to T. spengleri, but is distin- 

 guished by the following characters : the form is broader ; the 

 whorls are more constricted above the peripheral nodes ; the granu- 

 lation is finer, and often on the last whorl is wholly lost, or trans- 

 formed into small, irregular ridges ; the peripheral nodes are narrow, 

 long, often claw-shaped and crooked ; the base is slightly concave, 

 and the ground color is greenish. (Lischke.) 



Figs. 76, 77 represent a depressed variety. 



T. BICREXATUS Gould. PI. 16, figs. 62-65 : PL 12, figs. 68, 69. 



Shell low, pyramidal, acute at apex ; base and height nearly the 

 same ; base flat, pale yellowish, marked with delicate equal and 

 equidistant beaded revolving lines ; umbilical pit like a vortex, of a 

 smooth ivory white polish ; whorls 7 to 8, slightly excavated ; basal 

 edge acute, and furnished with about 15 scallops ; above this are 

 three lines of beaded granules, arranged also in oblique lines, which 

 extend in the form of slight folds to the edge of the periphery, pro- 

 ducing, by their extension, three or four crenulations of a rose-tint 



