PROSOBRANCHIATA. 245 
No. 165. Preuroroma coarctata. F. LH. Edwards. Tab. XXVIII, fig. 12, a—c. 
P. testé sub-fusiformi, costellatd, concentrice lineatd: spird elevatd, conoided : 
anfractibus convexiusculis, antice valde coarctatis ; postice unico sulco exaratis, ad suturam 
tuberculatis ; costellis arcuatis, per-brevibus ; apertura ovali, in canali brevi, latiusculo, 
exeunti ; labro arcuato, inttis dentato ; sinu sub-trigono, profundo, in margine collocato. 
Shell elongate, fusiform, ornamented with longitudinal ribs and sharp, concentric, 
raised lines: the spire, which is composed of seven or eight whorls, is rather conical, 
pointed, and elevated, forming almost two thirds of the whole length of the shell. 
The whorls are slightly convex, and suddenly much contracted towards the middle, 
so as to be almost angulated; a deep concentric furrow runs round the posterior 
margin, the sutural edge of which is thickened and presents a single row of round or 
oblong tubercles, varying in size in different specimens: the ribs are arched, sharp, 
and rarely extend beyond the middle of the whorl. The aperture is oval and 
terminates anteriorly in a short, wide canal; the outer lip is arched, sharp-edged, 
and armed within with two or three teeth, the largest of which is placed immediately 
in front of the sinus; the sinus itself is deep, sub-trigonal, and wide, occupying 
the whole breadth of the margin. 
This Pleurotoma is smaller and narrower than P. cxxzexa, to which it bears some 
resemblance; but the contracted whorls and short ribs distinguish it from that 
species. 
Size—Axis, rather more than 5-12ths of an inch; diameter, 2-12ths of an inch. 
Locality —Highchff, where it is not uncommon. 
No. 166. Pxievroroma microcnEita. VF. #. Hdwards. Tab. XXVIII, fig. 8, a—/. 
P. testé parva, crassa, fusiformi, nodulosd: spird obtusd: anfractibus convexiusculis, 
ad humeros sub-angulatis ; marginibus posticis canaliculatis, ad suturam unica serie tubercu- 
lorum ornatis; ultimo anfractu costellas angustas et lineas concentricas acutas, sese 
decussantes, gerenti : apertura elongato-ovali, in canali per-brevi terminanti ; labro leviter 
arcuato, acuto, intits incrassato, plicifero; sinu lato, sub-profundo, sub-trigono, anticd 
in margine collocato. ; 
Var. provucta, testa angustiori ; spird elevatiori ; lineis spiralibus eminentioribus. 
Shell small, thick, fusiform, and having the whole surface ornamented with 
concentric rows of round, knob-like tubercles: the spire, which equals the last whorl 
in length, is obtuse and pointed: the whorls, six or seven in number, exclusive of the 
