160 DR. J. E. GRAY’S SYNOPSIS OF 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 1846 (xviii. 362, 
t. 6), 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 Binué (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. 
Alligatoride, Gray, Cat. Tortoises &e. B. M. 56, 1844. Huxley, Journ. Proc. Linn. Soe. iv. 3. 
Alligator, Cuvier. Gray, Ann. Phil. x. 195. 
Teeth strong, unequal; the hinder ones differ 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 premaxilla and maxille. 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 
different 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. 1= Caiman palpebrosus, p. 161; 2. J. punctulatus, t. 2=Jacare punctulata, 
p. 159); and Caiman, or Jacare, with blunt nose (including 1. C. niger, t. 4=Jacare 
nigra, p. 167; 2. C. fissipes=Jacare latirostris, p. 167). 
His figures are very good representations of the species—indeed, the best knowh. 
MM. Duméril 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 two 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. selerops: according to Spix the 
dorsal scales are elongate. 
2. A. cynocephalus, p. 86, Caiman fissipes, Spix, Bras. t. 3. Head short, broad, 
thick, a ridge in front of each eye, the upper eyelid rugose. Nape with two rows of 
6 ey he 
an 6 ie 
