364 



ZOOLOGY. 



nervous ganglia much concentrated and protectedby an imperfect cartf'n. 

 ginous caps-ale ; pharynx armed with two teeth like a parrot's beak, be. 

 fides an odontophore. Sexes distinct. Usually development is direct, 

 with no metamorphosis ; segmentation of the yolk partial, and a primi- 

 tive streak is present as in birds and reptiles. 



Order 1. Tptrabranchiata With four gills. (Nautilus, living ; Or- 



thoceras, Goniatites, Ammonites, extinct.) 



Q~&e>r 2. Dibranchiata. With two gills. (Spirula, Belemnites, ex- 

 tinct, Sepia, Architeuthis, Loligo, Ommastrephes, Octopus 

 Argonauta.) 



TABULAR VIEW OP THE CLASSES OF MOLLUSCA. 

 Cephalopoda,. 



Cephalophora. 



Lamellibranchiata. 





MOLLUSCA. 



Laboratory Work. The cuttles are not easy to dissect. A horizon- 

 tal section through the head will show the relations of the cartilaginous 

 capsule to the brain, optic nerves and eyes. The nervous ganglia can 

 only be traced after tedious dissection. To study the viscera freshly- 

 killed specimens are quite essential. 



LITERATURE. 



Mollusca in general. Woodward : Manual of the Mollusca (Lon- 

 don, 1868). Lankester: Art. Mollusca in Encyclopaedia Britanuica. 

 Gould: Invertebrate of Massachusetts (1870). With the works of 

 -Cuvier, Huxley, Leuckart, Kiener, Sowerby, Say, Reeve, Tryou, H. 

 and A. Adams, D'Orbiguy, Hancock, Biuney, Verrill, Dall, etc. 



Lamellibranchiata. ^Lacaze-Duthiers : treatises in Anuales des Sc. 

 mt. Paris, 1854-61; i.e., Auomia (1854), Mytilus (1856); and Archives 

 , <le Zool. Exp. 1883-87; Aspergillum (1883). With essays by Bojauus, 

 Loveu, Peck, Mitsukuri, Brooks, Ryder, etc. 



Anatomy and Development of the Oyster. Brooks: Development of the 

 American Oyster (Studies from Biol. Lab., Johns Hopkins Univ., i. 

 1879); The Oyster, Baltimore, 1892. With essays by Ryder, Osboru, etc. 



Cephalophora. Essays by Brooks, Fol, Rabl, Lacaze-Duthiers 

 <Dentalium. 1856-57), Purpura (1859), Haliotis (1859), Vennetus (1MO). 

 Testacella (1887), Lankester. etc. 



Cephalopoda. Owen : Memoir on the Pearly Nautilus, 1832. With 

 the essays of Mailer, Steenstrup, Ki.' 1J1 - - ftrenacher, Verrill, etc. 



