PROSOBRANCHIATA. 251 
and thence tapers gradually towards the front, so as to form a wide and short, but 
distinct, canal; the aperture is of a compressed-oval shape; and the sinus, which is 
placed in the marginal furrow, is wide, shallow, and triangular in form. 
The general resemblance between the present species and P. turgidula might 
suggest the propriety of uniting the two; but, on a careful examination, differences 
will be found which seem to justify their separation. Thus, in the present species, 
the spire is more obtuse ; the whorls more contracted in front ; the posterior margins 
deeply furrowed and bordered at the suture by a broad, thick band; the longitudinal 
ribs are more numerous, more decided in character, and less oblique ; and the sinus 
is shallower and more pointed. 
A specimen in my cabinet, obtained from the Artesian well at Southampton, has 
the surface of the shell spirally furrowed instead of banded, and the anterior canal 
a little shorter and wider. These differences, however, do not appear to be 
sufficiently important for specific distinction, and I have therefore regarded the shell 
in question as a variety of the present species. 
Size.—Axis, 6-12ths of an inch; diameter, rather more than 2-12ths of an inch. 
Localities.—Highgate, Southampton. 
No. 172. Pteurotoma tureiputa. F. H. Edwards. Tab. XXIX, fig. 4, a—c. 
P. testa fusiformi, sub-turritd, spiraliter sulcatd, costellatd: anfractibus sub-ventricosis, 
ad humeros angulatis, postice declivis vie cavatis, ad suturas unicd serie granularum 
instructis ; sulcis spiralibus irregularibus, minime profundis, fere obsoletis ; costellis obliquis, 
angustis: aperturd ovali, antice in canali breviusculo exeunti; labro arcuato; sinu sub- 
trigono, latiusculo, media in margine collocato. 
Shell fusiform, sub-turreted, concentrically furrowed, and longitudinally ribbed ; 
the spire, formed of six volutions exclusive of the pullus, is moderately elevated, 
forming rather less than half of the shell: the whorls are roundedly convex, almost 
ventricose, and bluntly angulated at the shoulders; the posterior margins, which 
slope gently backwards, are nearly straight, and the sutural edge is girt by a single 
row of small, round tubercles. The concentric furrows are numerous, irregular, 
and almost obsolete over the posterior margins and middle of the whorls, but 
a little deeper and more perspicuous over the front; the longitudinal ribs are 
rather numerous, narrow, oblique, and very short, barely extending to the middle 
of the whorl, and slightly swelled at the posterior extremities; on the last whorl 
the ribs become reduced to small and not very prominent tubercles. The aperture 
is oval, and terminates in front in a short, but distinct and moderately wide, canal ; 
the outer lip is slightly arched; the sinus, placed in the very middle of the posterior 
margin, is wide, rather shallow, and somewhat triangular in form. 
