92 MANUAL OF NATURAL HISTORY, 



the structure of its denial, dental, osseous, digestive, sen- 

 sitive, and generative systems," but especially from the 

 construction of the nasal cavity, and the microscopic cha- 

 racter of the teeth and ossified parts of the endo-skeleton. 

 Its amphibian alliance is again chiefly supported by the au- 

 ricle of the heart being double, and by the large size of 

 the blood discs. But three species are as yet known ; one 

 from the Amazon (L. paradoxa), one from the Gambia 

 (Z. annectens), and the third {L. amphibia), discovered by 

 Dr. Peters, from the Quillemane marshes. Possibly these 

 may represent genera, for which the names of Lepidosiren, 

 Protopterus, and Rhinocryptis have been proposed to be 

 respectively appropriated. For further information, see 

 "Fitzinger," in "Wiegmann's Archiv," 1837, p. 232; 

 " Lepidosiren paradoxa," von Johann Natterer, Annalen 

 des Wiener Museums der Naturgeschichte, 1837, vol. ii. 

 p. 165; "Owen," in Linn. Trans., vol. xviii. ; "Owen's 

 Odontography," vol. i. p. 166; " Milne -Edwards, " in 

 "Ann. des Scien. JSFatur.," Sept. 1840, p. 159, and in 

 " Ann. and Mag. of Nat. Hist." vol. vi. 1841, p. 466 : also 

 papers, &c, by Jardine, Owen, Hogg, Miiller, Smith, and 

 Gulliver, in "Ann. and Mag. of Nat. Hist." vol. vii. 1841, 

 pp. 21, 211, 358; xvi. 1845, p. 348; and ii. 1848, p. 292; 

 "Owen's Lectures on Comp. Anat." vol. ii. pp. 78, 278 ; 

 "Gray's Brit. Mus. Cat. of Amphibia," P. ii. p. 61. 



TV. OKDER.— Ganoid-Fishes (Ganoidei). 



Endo-skeleton in some osseous, in some cartilagi- 

 nous, in some partly osseous and partly cartilagi- 

 nous ; exo-skeleton ganoid ; fins with the first ray 

 usually a strong spine; a swimming-bladder; 1 air- 

 duct. 



