GASTEROPODA. 



457 



dental ribbon of Risella is above 2 inches long, and coiled as in Llto- 

 rina, (Wilton). 



r, rostrum or muzzle, 



k, buccal mass. 



g, nervous ganglia 



(reproductive orifice, 

 on the right side). 



s, salivary gland. 



oe, oesophagus. 



/, lingual coil. 



m, shell-muscle. 



ft, branchia or gill, 



c, heart, 

 n, aorta. 



e, stomach. 



/, liver. 



h, biliary canal. 



i, intestine, 



o, anus, 



0, ovary. 



d, oviduct. 

 M, nidament. 



0', ovarian orifice. 

 X, reiial organ. 

 y, mucus gland . 



¥\Q. 'iir')\. Litorina litoralis ^: (after Souleyet ) Animal removed from its shell 

 branchial cavity and back laid open. 



Fig. 232. Operculum and teeth of i2Jse/Za. (Wilton.) 



Fam. 15. Calyptrceidce : teeth 3. 1. 3. (p. 131.) 

 Calyptreea. Pileopsis, Hipponyx. Metoptoma. 



