100 GASTEROPODA. 



terior margin of the cavity, near the necK. — anell obliquely 

 conical, anteriorly recurved, and the apex nearly spiral ; aperture 

 of a roundish oval ; the anterior margin shortest, and the pos- 

 terior one large and rounded ; the muscular impressions elon- 

 gated, arcuated, and transverse, situated under the posterior 

 margin. 



Pikcpsis Ungarica. — The Hungarian Pileopsis. Plate 

 XIV. fig. 31. Conical, vertex slightly spiral; longitudinally 

 striated, and transversely wrinkled ; covered with a fawn-colour- 

 ed pilous epidermis ; inside smooth, glossy, white, or rose-colour. 

 Two inches in diameter. Inhabits the seas of Europe. 



Genus 18.— FISSURELLA.— Lamarck. 



Generic Character. — Animal with the head truncated in front ; 

 two conical tentacula, with eyes at their exterior base ; mouth 

 simple, terminal, and destitute of jaws ; two pectinated branchite 

 projecting from the cavity ; mantle large, protruding beyond the 

 shell. — Shell shield-shaped, conically depressed ; concave within ; 

 the vertex perforated ; destitute of a spire ; and of an oblong- 

 ovate shape. 



Fissurella Groeca. — The Greek Fissurella. Plate XIV. 

 fig. 20. Ovate-oblong, convex ; the vertex with an ovate per- 

 foration ; striae cancellated and elevated, and the sections tuber- 

 culated ; opening oblong-ovate, white or bluish ; outside yellow- 

 ish-brown, sometimes clouded. Half an inch long. Inhabits 

 the European seas. 



Genus 19 SIP HO — Brown. 



Generic Character. — Animal unknown. — Shell subconic, ver- 

 tex turned to one side, slightly spiral, with a small fissure near 

 the apex ; inside having a rhombic funnel-shaped syphon, corre- 

 sponding with the external fissure ; ovate. 



Sipho striatus. — The Striated Sipho. Plate XIV. fig. 21. 

 White, with strong divergent striae and faintly striated concentri- 

 cally ; margin slightly crenulated ; the fissure triangular. Three- 

 eighths of an inch long. Inhabits the sea at Greenock. 



