REPORT ON ZOOLOGY. l75 



ducihranchia ; and Sect. 2. Amphipneusta {Immulahilia), com- 

 prising the two orders of Cryptohranchia and Perennihranchia. 

 The most recent work in this department is that by Dumeril 

 and Bibron*, of which only the first volume has appeared hi- 

 therto, containing remarks on the organization of Reptiles in 

 general, and the Chelonians in particular. There is also a very 

 complete Bibliography with reference to this branch of zoology. 

 The systematic portion of the work is not yet entered upon. 

 The authors, however, have it in view to adopt the same orders 

 as those of Cuvier. 



The above are the principal authors who have treated of this 

 class as a whole, but some of its orders have received the par- 

 ticular attention of different naturalists, and derived much illus- 

 tration from their researches. No one has contributed so much 

 to our knowledge of the Chelonian Reptiles as Mr. Thomas Bell. 

 Several memoirs from him on these animals are to be found in 

 the Linnoean Transactions and Zool. Journal, amongst which 

 I may more particularly mention his " Monograph of the Tor- 

 toises having a moveable Sternum " published in 1825 f, and his 

 '*C haracters of the O rder, Fam ilies, and Genera of the J<^5^^<fZm«/a " 

 published in 1828 J. More recently (1833) Mr. Bell has com- 

 menced a splendid work § on this order, in which it is intended 

 to describe and figure all the known species, arranged according 

 to their affinities. Seven parts have already appeared, which 

 for beauty and accuracy of illustration it is impossible to surpass. 

 Before quitting this group I may just allude to a paper in the 

 Ann. des Set. for 1828||, by MM. Isid. Geoffroy St. Hilaire and 

 J. G. Martin, on some parts of the internal organization of these 

 Reptiles. Being purely anatomical, I should not have noticed it, 

 did it not contain the statement of a curious fact respecting the 

 affinity well known to exist between the Chelonia and the Mo- 

 notremata. It is observed, that with regard to the urinary ap- 

 paratus, the analogy between the Ornithorhynclms and the Tes~ 

 tudo Indira is even much greater than that which is found be- 

 tween this last species and many other reptiles belonging to the 

 same order. 



The Emydosauria were closely investigated by Cuvier and 

 Geoffroy, by the former more especially, in the early part of 

 the present century, and since their researches %, I am not 



• Erpetologie generale, ou Histoire Naturelle Complete des Reptiles, torn. i. 

 Paris, 1834. 



+ Zool. Journ., vol. ii. p. 299. J Zool. Journ., vol. iii. p. 513. 



§ Monograph of the Tesfudinata. fol. 1833, &c. || torn. xiii. p. 153. 



If See tlie earlier volumes of the y/ww. du Miis., more particularly vol. x., con- 

 taining a valuable memoir by Cuvier on the different species of living Crocodiles, 

 and their distinctive characters. For the structure of these animals, sec his 

 Ossemem Fossiles. 



