48 TROCHUS. 



genus, I do not see my way clear to make such a separation. Con- 

 chologically, such species as C. villanus Phil., are very near to T. 

 scabrosus Phil., etc. ; and finally, when we see that neither the teeth 

 of the columella nor of the outer lip are constant in nearly all the 

 species, nor the form of shell, peculiar umbilicus nor granulated 

 sculpture can be depended on for generic characters, it is clear that 

 the group can have no higher rank than Tectus, Infundibulum, and 

 other subdivisions under 'Prodi us. 



As to the grouping of the species I have not been able to discover 

 any mode of division into sections wholly satisfactory to myself. 

 Perhaps the species are best grouped by a division into two sections; 

 Clancnlus including those with strong basal tooth to the columella, 

 and Clanculopsis for species with only a small denticle at the base. 

 Each of these sections may be divided into species with the columella 

 solute or tortuous above, inserted at or near the center of the axis in 

 the bottom of the false umbilicus, and those with the columella 

 inserted upon the edge of the umbilieus, and not deeply entering. 

 Perhaps this last distinction is the more fundamental of the two. 

 There are a number of species which greatly resemble species of 

 Gibbula of the section Eurytrochus. Of course the resemblance is 

 wholly superficial, as there is no real relationship between the forms. 



Section TLAM-TUIS (,s-. .sfr.) 

 T. niAUAoxirs Linne. PL 15, figs. 54- 5<>. 



Depressed conoidal with rounded periphery and profoundly 

 umbilicate axis, very strong and solid, densely granulate, coral red; 

 spire conoidal, its outlines scarcely convex; whorls about 6, some- 

 what convex, separated by well impressed sutures, the last large, 

 deflected anteriorly, bearing 18 or 19 crowded, closely granose 

 cinguli, of which the 1st, 3d, 5th, 7th, 9th and two upon the base are 

 composed of alternate black and white granules ; upon the base the 

 granulation is finer ; the base is convex, a trifle indented toward the 

 center; aperture oblique, subtetragonal, peristome with a marginal 

 row T of black and white dots ; outer lip plicate within, with a short 

 pliciform tubercle above ; basal lip, outer margin of the umbilicus 

 and parietal wall provided with wrinkle-like plicse ; columella very 

 oblique, terminating below in a square prominence, contorted above, 

 and inserted on the side of the umbilicus ; umbilicus white, and 

 within the strongly radiately plicate marginal rib, smooth. 



Alt. 18, diam 23 ; alt. 16, diam. 18 mill. 



Red Sea, 



