CATALOGUE OF SHIELD KKl'TTLES. 



Run. III. ALLIGATORID.E. 



The upper and eleventh lower teeth Longer, like canines, 

 the canines of the Lower jaw fitting into holes or perfora- 

 tions on the edge of the upper jaw. 



Alligatoridffi, Cm-/. < 'at. T.;-t. .<•-■. 11. M. p. 56, 1844 ; ZVans. 

 /«■'. S . 1869, \i. p. 160. 



llu.vhii. ./ .... /',,<.. /.//),-. Sfoc. iv. p. 3. 



Alligator, On-/, r. 



I in, /Vh7. x. p. 195. 



Tooth Btrong, unequal, the hinder ones differ in shape 

 from the anterior. The front pair of mandibular tooth 

 and the fourth pair (canines) are received into pits on the 

 edge of the pnamazilla and maxilla;. The mandibular 

 teeth behind these pass inside and not between the maxil- 

 lary tooth. 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 neek-shield of the different species. He has figured 

 some varieties or species very nearly allied to those hero 

 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 palpebro- 

 .-">•. p. 161 j 2. J. puaetulatus, t. 2=Jaeare puiictulata, 

 p. 159); and Caiman or Jacare, with blunt nose (including 

 1. C. niger, t. 4= Jacare nigra, p. 167; 2. C.fiss!pes= 

 Jacare latirostris, p. 167). 



His figures are very good representations of the species 

 — indeed the best known. 



MM. Dumeril and Bibron admit the three species de- 

 scribed and figured by Spix, thus : — 



1. A. sclerops, p. 74 (Caiman noir, Spix, Bras. t. 4). — 

 Head elongate, flattened ; a ridge iu front of each eye ; 

 upper eyelid finely striated. Nape with two roivs of small, 

 oval, compressed scales. Back with two central longitu- 

 dinal 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. sclerops: 

 according to Spix the dorsal scales are elongate. 



2. A. cynocephahis, 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 large, 

 square, keeled shields. Back scale keeled, the last three 

 cross bands of four scales. Sides with some strongly keeled 

 scales. Back green, black-dotted. 



;!. A. punotulatus, p. 'i\ (Spix, Bras. t. 2). — nead elon- 

 gate ; nose flattened, with a rounded point in front, with- 

 out any preocular ridges; upper eyelid rugose. Nape with 

 two rows of shields. Back Hat, scarcely keeled. Sides 

 with some Larger scales. Yellow, black-dotted. 



John Natterer, in his ' Beitrag zu den siid-amerika- 

 nischen Alligatoren,' editod by Fitzingcr, describes eight 

 species of the genus Champsa : five have partly bony eye- 

 lids, and three have them entirely bony. The five former 

 belong to the genus under consideration. 



The preorbital ridge distinct ; beak broad, with three 

 Lateral foveolffi; eyelid striated; beak broad and blunt: 

 ('. nigra, t. 21. 



The nuchal scutella many, in three series: C. fissipes, 

 t. 22. 



The nuchal scutella many, in two series : C. sclerops, t. 23. 



The preorbital ridge evanescent ; beak without lateral 

 foveoltfi ; eyelids rugose ; the frontal ridge flexuous, bent 

 in front : C. vallifrons, t. 24. 



The frontal ridge arched, bent back : C.punctulata, t. 25. 



M. Natterer gives the following proportional measure- 

 ments of the heads : — 



The figures of the beads of the last two species differ 

 from that of C. sclerops chiefly in the nose being narrower 

 (C. punctulata being the narrowest and very slender), nar- 

 rower than in any specimen that has come under my 

 observation ; the lower jaws in the figure also differ in shape, 

 that of C. vallifrons being the most slender. Dr. Strauch, 

 who had M. batterer's specimens to examine, regards the 

 two latter as the same species, but distinct from sclerops. 



Srsopsis of the Genera. 



I. The ventral scutella like the dorsal ones, bony and artictdated 

 together, forming a shield. The eyelids with an internal 

 bony plate. The cervical scutella in pairs, forming an elon- 

 gated shield. Nasal bone short. Tropical America. 



1. Jacare. The orbits united by a bony cross ridge. Eyelids 



partly striated or rugose. 



2. Caiman. The orbits not united by a cross ridge. Eyelids 



bony, entirely smooth. 



