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 by a 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 Emarginida. PI. IX. 

 Jliiimal. Body creeping, with two, conical, tentacular eyes at 

 the external base ; mantle large, 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 branchise projecting from 

 the cavity ; mantle large, 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. 



