REPORT ON ZOOLOGY. 213 



illustrative department, is unrivalled in the beauty and accuracy 

 of its delineations. It is also extremely valuable from the num- 

 ber of dissections which it contains. 



There are also many other valuable monographs, not published 

 separately like those already alluded to, to be found in Germar's 

 Magazin tier Entomologie, Guerin's Magasin de Zoologie, 

 Silbermann's R^vue Entomologiqiie, in the Entomological Ma- 

 gazine, and in t\\eAnnales de la Soc. Entomologique de France. 



In concluding my remarks on this department of zoology, 

 I may observe that it has received a powerful impulse from the 

 recent establishment of two Entomological Societies, one in 

 France, and the other in our own country. This last was only 

 instituted in 1833*. 



III. MOLLUSCA, CuV. 



It is undoubtedly to the researches of Poli, Cuvier, Lamarck, 

 Ferussac, and Blainville that we are to attribute the great advance 

 which has been made of late years in our knowledge of the ani- 

 mals belonging to this tj^e. Poli's work, consisting of two 

 volumes, on the anatomy of the Bivalve and Multivalve Testacea, 

 is well known. In 1826, a third volume was published by 

 Chiage, in which the anatomy of the Univalves was commenced 

 upon the same plan as that adopted in the two former volumes. 

 Cuvier's Memoirs on the Mollusca, most of which had been pre- 

 viously inserted in the Annates dii Blusdiim, were in 1816 col- 

 lected by himself into one volume and published separately. 

 They contributed greatly to our better knowledge of the natural 

 affinities of these animals, and furnished the basis of the system 

 developed the year following in the R^gne Animal. In this 

 last work the Mollusca are divided into six classesf , Cephalo- 

 poda, Pteropoda, Gasteropoda, Acephala, Rrachiopoda, and 

 Cirrhopoda, the characters being derived from the general form, 

 between which and the internal structure Cuvier observes there 

 is a pretty constant relation. The Cephalopoda are simply 

 divided into genera according to the nature of the shell. The 

 Pteropoda, a class instituted by himself in 1804 for the recep- 

 tion of the genera Clio, Pneumoderma, and Hyale, are divided 

 into two sections, founded on the presence or absence of a di- 

 stinct head. The Gasteropoda are distributed under seven orders, 

 characterized according to the position and form of the respira- 

 tory organs. The Acephala comprise the two orders of Testa- 

 ceous and Naked Acephala. The JBrachiopoda include the genera 



* Since this Report was read, the Entomological Society of London has pub- 

 lished the first part of a volume of Transactions, containing several interesting 

 and important communications on this branch of Zoology. 



t Three of these classes, Cephalopoda, Gasteropoda, and Acephala, had been 

 established by Cuvier in his 2abl. E'lem. de I'llkt. Nat, in 1798. 



