254 MAZATLAN UNIVALVES 
size, and there were no intermediate specimens, I have not ven- 
tured to affiliate them. It differs from T. politum in the 
absence of sculpture, (which however would hardly be detected, 
even under the microscope, without the description,) in the 
greater reflection of the labrum over the spire, and in the very 
much smaller size. Long. °05, lat. *11 by ‘07, div. 180°. 
Hab.—Mazatlan; 1 sp. and fragment off Spondylus; L’pool 
Col. 
Tablet 1174 contains the specimen. 
324. TEHINOSTOMA SUBSTRIATUM, 2. s. 
T. t. minima, planatd, opacd, alba, subnitente ; striulis 
spiralibus prope suturam tmpressam monstrantibus ; callositate 
angustissima, longiore, circa rimam umbilicalem gyrante, prope 
labium vie planato ; apertura rotundata ; labro solido, anfr. 
penult. haud anplectante. 
This tiny species is known from T. amplectans by the outer 
lip not being reflected over the spire, which clearly displays 
the substriated whirls. The callosity is long, but narrow, and 
searcely planate at the aperture. A fragment has the suture 
less impressed. Long. °016, lat. 043 by °032. div. 170°. 
Hab.—Mazatlan ; 1 sp. (not quite perfect) and a fragment ; 
P’pool Col. 
Tablet 1175 contains the specimen. 
325. TrocHus ————,, sp. ind. 
Tablet 1176 contains a fragment of a white shell, tuberculous, 
with the basal keel smooth; found in additional materials: 
after the genus had been completed. 
Hab.—Mazatlan ; extremely rare, off Spondylus ; L’pool Col. 
——_—. 
Tablet 1177 contains an operculum not affiliated to any 
known multispiral species. (That of species 291 is however 
unknown.) It is light horn-coloured, extremely thin, with 
only about 10 whirls ; margin irregular ; scar lateral. 
Tablet 1178 contains 2 worn, small, strong, Turbinoid oper- 
cula, remarkable for the number of whirls, there being at 
least 10 in a diameter of *046. 
