68 TROCHUS. 



of alternating white and black granules ; last whorl globose, bearing 

 15 or 16 Iira3, somewhat convex beneath, the concentric line uniform 

 yellowish-brown, often in pairs, separated by single alternately white 

 and black articulated lira? ; aperture oblique, rhomboidal ; lip thick- 

 ened, plicate, dentate above, columella oblique, terminating in a 

 large, plicate, contorted, truncate tooth ; umbilicus profound, narrow, 

 its border crenulated ; parietal callous wrinkled. 



Alt. 11, diam. 11 mill. (Fischer.') 



Seychelles Is. 



T. rarus (Dufo) FISCHER, Sp. et Icon, genre Trochus, t. 96, f. 1. 

 -T.flosculus FISCHER, Coq. Viv., p. 300, t. 96, f. 1. (1880.) 



This form was at first identified by Dr. Fischer with the T. rarus, 

 of Dufo (Ann. des. Sc. Nat. 2e. Ser. xiv, 1840, p. 188). This form, 

 however, cannot be certainly determined from Dufo's miserable 

 description, and had better be dropped altogether ; or, as Fischer 

 suggests, be relegated to the synonymy of T. pharaonius. 



T. MARGARITARIUS Philippi. PI. 13, fig. 90. 



Shell conical, umbilicate, ornamented with granose cinguli (about 

 7 on penultimate whorl), brown, the 2d and 4th cinguli ornamented 

 with black, 6th and 7th with alternating brown, white and black 

 granules ; margin of the umbilicus dentate ; columella solute above, 

 terminating in a plicate tooth below ; lip dentate within. 



The grains of the second and fourth rows are much smaller than 

 the rest, and are formed of alternating white and black grains. The 

 base shows 10 concentric rows of granules, in which every fourth 

 granule is black. The aperture and the umbilicus are formed just 

 as in T. pharaonius. In all varieties the ground-color is a dirty 

 flesh-color, and alternating series of granules white and black 

 articulated. Alt. 12, diam. 14 mill. (Philippi.) 



3Lonodonta margaritaria PHIL., Zeitschr. f. Mai. 1846, p. 100. 

 T. margaritarius PHIL., Conchyl. Cab., p. 74, t. 14, f. 4. 



Philippi quotes as possibly the same as margaritarius the figure 

 of T. clangulus, in Wood's Index Test. It is not that species, how- 

 ever. It may be allied to stigmatarius. 



T. AMCENUS Koch. PI. 42, figs. 19, 20. 



Shell elevated conical, false-umbilicate, granulate ; whorls plane, 

 the last rounded-angulate ; granose cinguli 4 or 5, first and third 

 pale pink, second, fifth and basal (6 to 7) cinguli whitish, every 



