HYALINIA CELLARIA. 3 
Binney’s more recent figure, given in the Proc. Acad. Nat. Sei. Philad., in 
1875, would appear to be that of the true cedlaria. he figure given by 
Morse and reproduced by Binney as representing the dentition of /7. 
cellaria, 18 apparently not from the radula of that species, but more 
probably belongs to HH. lucida. 
Diagnosis.—Though /Hyalinia cellaria is very near to H. lucida, it is 
in its typical condition very distinct, and may be distinguished from that 
species by its smaller size, fewer volutions, flatter spire, more impressed 
sutures, and its more delicately-tinted and thinner shell; the aperture is 
also more flattened basally and more perpendicular to the axis of the shell. 
The ANIMAL is pale grey, slightly darker on back and head, with paler 
foot-sole ; the mantle-margin is speckled with a dark fawn colour, and 
differing markedly from //. /ucida, in which the mantle-margin is never 
spotted, and in which the body is always so dark. 
INTERNALLY, the visceral chain of gangha does not display the striking 
obliquity shown by //. /ucida, and the approximation of the constituent 
gangha is more pronounced; the conjoined penis-sheath and epiphallus 
is shorter and more uniform in calibre, somewhat scimiter shaped, and 
without the characteristic twist seen in lucida; the radula shows only 
two true laterals at each side, the third being transitional. 
Description.— ANIMAL slender, blackish-grey above, and finely granulated, with 
a row of comparatively large and prominent tubercles down the middle of the back 
bounded by the well-marked DORSAL GROOVES ; sides paler, translucent grey, with 
coarser granulation below and behind the LATERAL GROOVES ; MANTLE of a some- 
what whitish-grey, except at the collar, around the RESPIRATORY ORIFICE, where it 
is irregularly and densely spotted with a dark fawn colour, which shows through 
the shell as a broad and gradually darkening margin towards the aperture ; 
OMMATOPHORES long and slender, distinctly bulbous at the 
ends, and showing the RETRACTORS as a darker core; LOWER 
TENTACLES short and translucent-grey ; FOOT slender, pointed 
behind, SOLE indistinetly tripartite, PEDAL GROOVES united at 
the tail above a longitudinal mucus-pore. 
H. cellaria also, according to Dr. André, presents a peen- 
liarity not yet noticed in other species, and of which the 
function is as yet unknown; this consists of about one hundred 
crypts or depressions on the right side of the body, but limited 
to the region between the genital orifice and the mouth, 
hecoming fewer towards the dorsum. These invaginations of Fic. 54, — Section 
the external epithelium may be simple, ramified, ov expanded, through right moiety 
but generally contract at the external orifice, and have an 0 body of 47. cedlarta 
5 y : “ salt showing ‘‘ crypts’ and 
extreme depth of a quarter to one-third of a millimetre, that location of phylaco- 
is about half the thickness of the body-wall; their epithelial — blasts x 10(aft. André) 
cellules are double the usual leneth and without vibratile cilia. 6.c. body cavity ; ¢. 
=e ‘ ie . : crypts; #z. mantle ; 
Phe finely-granular structureless tissue beneath is thicker than position of phylaco- 
the epitheliuin, and is said to be peculiar to Hyalinia, and is _ blastsare indicated by 
slightly stained by carmine. black cells on dorsum. 
In crawling, the shell is usually carried inelined to the right side, and the tail of 
the animal does not extend quite to the margin of the shell. 
Mucus thin, colourless, and slightly iridescent. 
SHELL very depressed and almost discoid, more convex beneath, thin and brittle, 
very glossy, smooth, aud semitransparent, of an amber or yellowish-horn colour 
above, and whitish, with often a greenish or bluish tinge around the umbilicus, 
Which is comparatively narrow, but deep and slightly overspread by the apertural 
margin ; LINES OF GROWTH shallow and indistinet, slightly puckered at the sutures 
and microscopically striate ina spiral direction ; SUTURE with a channeled aspect 
and showing often as a darker line ; EPIDERMIS comparatively thick ; WHORLS 5-6, 
regularly but slowly increasing ; SPIRE slightly raised ; APERTURE broadly lunate, 
and slightly oblique, with simple and direct’ margins, the basal margin slightly 
reflected over and encroaching on the umbilicus, the upper margin projecting 
beyond the lower. 
