116 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE. 
costulis transverse dense-striatis ; basi subconverd dense costulatdé et concentricé striatd ; 
umbilico nullo. 
Shell conical, but depressed ; whorls (4—5) flattened, encircled with closely-arranged, 
nearly equal rounded ribs; the ribs are densely striated longitudinally ; the base is rather 
convex, having very closely-arranged costa, crossed by concentric striz ; no umbilicus. 
The junctions of the whorls are rather obscurely marked, and the lower margin of the 
last whorl is angulated. The little ribs upon the base are very delicate and fine; the outer 
lip is imperfect, and does not enable us to describe the aperture; but there is nothing 
visible upon the surface of the whorls which would indicate that it belongs to Pleurotomaria. 
The height is two thirds of the basal diameter. 
Locality. Scarborough. In Mr. Leckenby’s cabinet. 
Trocuvus monititectus, Phil. Plate XV, figs. 1, 1a. 
Trocuus MONILITECTUS, PAil. 1835. Geol. of York., vol. i, t. 9, fig. 33. 
—_ os D’Orb. Prod. Paléont., p. 265. 
T. Testd conicd, anfractibus (8) planis, suturis obscuris 4—5 costatis ; costis crebris 
oblique crenulatis. 
Shell conical, volutions (8) flattened, with indistinct sutures, and encircled with 4—5 
rows of coste; the costz are closely arranged, and crenated obliquely. 
The costa are large, the crenations closely arranged, and pass obliquely from left to 
right. Length 43 les, basal diameter 33 lines. 
Locality. Near Scarborough. The original specimen figured by Phillips. 
Turso ELABoRATUS, Bean. Plate XV, fig. 2, 2a; and Plate IX, figs. 27, var. 
9 ? to) fo) 
TuRBO ELABORATUs, Lycett. 1850. An. Nat. Hist., vol. vi, p. 416, pl. 11, fig. 1. 
T. Testa subturritd, apice acuto, anfractibus (4) subconvewis, superne planis, inferne 
costulis longitudinalibus numerosis, aliis transversis decussantibus ; anfractu ultimo ventricoso 
obliquo, apertura ovata. 
Shell turreted, apex acute, whorls (4) convex, their upper borders flattened horizontally, 
their sides and lower portions, with numerous longitudinal ribs, transversely decussated 
by others ; last whorl oblique ; aperture entire, ovate. 
The longitudinal ribs are rendered nodulous by those which are transverse ; the latter 
are 4 or 5 in number; the last volution has numerous encircling ribs, but the longitudinal 
ones do not extend beyond the middle of the volution; and when more than four whorls 
have been completed, the last whorl is destitute of longitudinal ribs, but in lieu of them are 
