160 DK. J. E. GEAY'S SYNOPSIS OP THE SPECIES 



comparison of the specimens on which these species were founded shows how much 

 better it is to refer to nature than to depend on figures and descriptions, which are 

 liable to the imperfection attending human observation and record. 



Dr. Falconer, in the ' Annals and Magazine of Natural History ' for 184G (xviii. 362, 

 t. 0), described and figured a skull of this species under Cuvier's name, which was in 

 the Belfast Museum, and said to have been sent from Sierra Leone. 



Dr. Balfour Baikie described the skull of a specimen from the River Binue (see 

 Proc. Zool. Soc. 1857, p. 58). 



Family III. ALLIGATORID^. 



The upper and eleventh lower teeth longer, like canines, the canines of the lower jaw 

 fitting into holes or perforations on the edge of the upper jaw. 



Alligatorida, Gray, Cat. Tortoises &c. B. M. 56, 1844. Huxley, Journ. Proc. Linn. Soc. iv. 3. 

 Alligator, Cuvier. Gray, Ann. Phil. x. 195. 



Teeth strong, unequal ; the hinder ones diflfer in shape from the anterior. The front 

 pair of mandibular teeth, and the fourth pair- (canines) are received into pits on the 

 edges of the prsemaxilla and maxillae. The mandibular teeth behind these pass inside 

 and not between the maxillary teeth. The premaxillo-maxillary suture on the palate 

 is straight or convex forwards. The symphysis of the lower jaw is short. 



Spix, in his work on Brazilian Lizards, gives very good figures of the Alligators, with 

 the colours well marked. The Memoir on South-American Alligators by Natterer, 

 contains very accurate and detailed figures of the head and the neck-shield of the 

 difl'erent species. He has figured some varieties or species very nearly allied to those 

 here noticed, which have not come under my observation. 



Spix divided the Alligators into two genera: — Jacaretinga, with acute nose (1. J. 

 moschifer, t. \ =■ Caiman palpehrosus, p. 161 ; 2. J. i^unctulatus, t. 2^Jacare punctulata, 

 p. 159); and Caiman, or Jacare, with blunt nose (including 1. C. niger, t. A = Jacare 

 nigra, p. 167; 2. C.Jissipes=^Jacare latirostris, p. 167). 



His figures are very good representations of the species — indeed, the best kno\vti. 



MM. Dumeril and Bibron admit the three species described and figured by Spix, 

 thus : — 



1. A. sclerops, p. 74 ; Caiman noir, Spix, Bras. t. 4. Head elongate, flattened, a ridge 

 in front of each eye, the upper eyelid finely striated. Nape with tivo rows of small 

 oval compressed scales. Back with two central longitudinal ridges, the three last cross 

 bands of six keeled scales. Black, yellow-banded. I have no specimen agreeing with 

 the account of the nuchal scales and the eyelid of A. nclerops : accordmg to Spix the 

 dorsal scales are elongate. 



2. A. ci/nocejjJtahis, p. 86, Caiman fissipes, Spix, Bras. t. 3. Head short, broad, 

 thick, a ridge in front of each eye, the upper eyelid rugose. Nape tvith two rows of 



