64 MALACOZOA. GASTEEOPODA. SCUTIBRANCHIATA. 



transverse narrow ribs, reticulated with longitudinal 

 raised lines, the ribs on the last turn divided into several. 

 Reticuldtus, marked like network. 



Genus 4. Rostellaria. — Shell turrite or fusiform ; its 

 aperture oblong, with a prolonged canal, the outer lip 

 much expanded, usually digitate or dentate. Named 

 from the long beak, Rostrum, formed by the canal. 

 Lamarck. 



1 . Rostellciria Pes-pelecdni. — Shell turrite, of ten con- 

 vex turns having a medial series of obhque compressed 

 obtuse odules, the outer lip extremely expanded, and 

 angulate. Named from a fancied resemblance to a Peli- 

 can's foot. 



Family VIII. — Cypr.eina. 



Body elongated, spiral; the head with two filiform 

 tentacula at the thickened base of which externally are 

 the sessile eyes ; mouth with a thin ribbon-like tongue, 

 minutely echinate ; the mantle with two very large lobes, 

 capable of being extended over the back of the shell ; 

 which is oval or oblong, convolute, with the spire very 

 short or concealed, the aperture linear, as long as the 

 shell, and denticulate on one or both sides. Name from 

 one of the genera, Cyjprcea. 



Genus 1 . Cypr^a. — Shell oval, convolute, very convex 

 above, with the aperture longitudinal, linear, having a 

 recurved notch at each end, both hps denticulate. 

 Named after Venus. 



1 . CyprcBa Europcea. — Shell ovate, very convex above, 

 with numerous transverse grooves. The only species 

 of northern Europe. 



A. C. Europcea, arctica. Arcticus, ncrthern. 



ORDER III.— GASTEROPODA TUBULIBRANCHIATA. 



ORDER IV.— GASTEROPODA SCUTIBRANCHIATA. 



Respiratory apparatus a cavity on the back, con- 

 taining pectinate or filamentous branchiae, and commu- 



