80 



CLASSIFICATION OP THE ANIMAL KINGDOM. 



(Bronn, Malacozoa Acephala, Die Klassen und Ordiiungen des Thier- 

 reichs, 1862 ; S. P. Woodward, A Manual of the Mollusca, 3d ed., 1875 ; 

 Stoliczka, The Pelecypoda of the Cretaceous Rocks of India, Palseontologia 

 Indica, 1875.) 



rs 



Fig. 73. Lamellibranchiata. Diagrammatic representation of the anatomy of a siphonate 

 Bivalve. The left valve and left mantle-lobe are removed, and the siphons are cut short, 

 it, Umbo ; ca, Cartilage-pit ; o, Mouth ; Ip, Labial palpi ; a, Stomach, surrounded by liver ; 

 si, Sac containing the crystalline stylet ; i i, Intestine, perforating the heart (h) ; r, Rec- 

 tum, terminating in the anus; ad, Anterior adductor; pd, Posterior adductor; n, Supra- 

 cesophageal or cerebral ganglion (the mouth is a little displaced upwards, so that the gang- 

 lion comes to lie below the gullet instead of above it) ; n', Parieto-splanchnic or branchial 

 ganglion ; / Foot ; xx, Cut edge of the right mantle-lobe ; rs, Retractor muscle of the siphons ; 

 br, Branchiae of the left side ; g, Generative glands; s, Inhalant siphon; s', Exhalant siphon. 



CLASS II. GASTEROPODA. 



SUB-CLASS I. BRANCHIATA. 



ORDER I. SCAPHOPODA. 



Fam. Dentaliidae. Dentalium. 



ORDER II. PROSOBRANCHIATA. 

 Section A. Siphonostomata. 



Fam. a. Strombidae. Strombus, Pteroceras. 

 Fam. b. Muricidse. Murex, Fusus. 



