92 - CONCHOLOGY. 
suspended vertically around ; head distinct, and slit below ; two 
conical contracted tentacula, at the base of which are placed the 
eyes, which are somewhat pedunculated; mouth below, funnel- 
shaped, oblique, truncated, and concealed ; branchial cavity open- 
ing anteriorly behind the head by a transverse fissure. 
Shell. Oblong, very depressed, slightly convex above, obtuse 
at extremities, anteriorly channeled bya slight sinus, and having 
towards the posterior part a small pointed apex, inclined back- 
wards; the lower surface slightly concave. Inhabits the Austra- 
lian seas. Four species. One fossil. 
Parmophorus Australis. Parmophorus granulata. 
P. brevicula. P. ambigua. 
2. Genus Emarginula. Pl. IX. 
Animal. Body creeping, with two, conical, tentacular eyes at 
the external base ; mantle Jarge, partly covering the margin of the 
shell ; foot very large and thick. 
Shell. Shield-like, conical; summit inclined ; the cavity simple, 
having a notch or hollow cut on its posterior margin; shells of 
this genus are generally very small. Inhabits the British seas. 
Five species. 
Emarginula Blainvillii. Emarginula fissura. 
E. Cuvierii. E. rubra. 
E. marginata. 
3. Genus Fissurella. PI. IX. 
Animal. With the head truncated in front ; two conical ten- 
tacula, with eyes at their exterior base; mouth simple, terminal, 
and destitute of jaws; two pectinated branchie projecting from 
the cavity ; mantlelarge, protruding beyond the shell. 
Shell. Shield-shaped, conical recurved, summit entire, de- 
pressed, concave below, perforated at the summit in the form of a 
key hole, without a spire; the exterior surface ribbed longitudi- 
nally. Inhabits the European and American seas. ‘Twenty-two 
species. - 
Fissurella Cayennensis. Fissurella Javanicensis. 
F. lilacina, F. fascicularis. 
