292 CROCODILIDB. 
Synopsis of the Species. 
I. Upper eyelid incompletely bony ; supratemporal fossz present ; 
tive teeth in each preemaxilla; 17 to 20 mandibular teeth on 
each side. 
A. Orbit produced anteriorly to the ver- 
tical of the ninth or tenth maxillary 
tooth; upper eyelid flat; vomer 
exposed on the palate .......... 1. niger, p. 292. 
B. Orbit not produced anteriorly; upper eyelid rugose, more or 
less distinctly raised into a small horn. 
The width of the snout, on a line with the > 
anterior borders of the orbits, equals its 
length; three or four transverse rows of 
large nuchals, only one of which is com- 
POSEd Ol LOUESCULES! .-y-s, ne sack ee 2. latirostris, p. 293. 
Snout longer than wide at the base; four 
or five transverse rows of large nuchals ; 
all the scutes on the body, limbs, and tail 
ONY In AHO aAduUlGe. ces 6 oo berg oe 3. sclerops, p. 294. 
II. Upper eyelid entirely bony; supratemporal fossee obliterated ; 
four teeth in each preemaxilla; 20 to 22 mandibular teeth on 
each side. 
Some or all of the scutes between the hind 
limbs in two or three longitudinal series ; 
caudal crest double up to the ninth or 
tenth vertici]l mclusively ............ 4. trigonatus, p. 296. 
All the shields between the hind limbs in 
four series ; caudal crest double up to the 
eleventh or twelfth verticil inclusively. . 5. palpebrosus, p. 296. 
1. Caiman niger. 
Caiman niger, Spia, Lacert. Bras, p. 3, pl. iv. (1825). 
Champsa nigra, Wagler, Syst. Amph. pl. vii. fig. 1 (1830) ; Natterer, 
Ann. Wien. Mus. ii. p. 320, pl. xxi. (1840), 
Jacare nigra, Gray, Cat. Tort. §c. p. 65 (1844), and Tr. Zool. Soc. 
vi. p. 162 (1867), and Cat. Sh. Rept. ii. p. 25 (1872). 
fissipes ?, Huxley, Journ. Linn. Soc. iv. p. 4 (1860). 
Alligator niger, Strauch, Syn. Crocod. pp. 17 & 71 (1866). 
18 (or 19) upper and 17 or 18 lower teeth on each side; fourth 
maxillary tooth much longer than the third. Head once and three 
fifths to once and two thirds as long as broad; snout moderate, 
obtuse, a little longer than broad; a feeble transverse ridge in front 
of the concave interorbital region, bordering two deep concavities ; 
two oblique ridges on each side of the snout, one from the orbit to 
