CATALOGUE OF SHIELD REPTILES. 



27 



Jacare punctulata, Gray, Ann. # Mag. Nat. Hist. 1862, 

 x. p. 329 ; Trans. Zool.Soc. 18G9, vi. p. 165. 



Hab. Brazil (Spiv) ; Surinam ; Argentine Republic (//. 

 Christy). 



Natterer figures two other species, under the name of 

 Champsa vallifrons (t. 24) (Jacare vattifrons, Gray, Cat. 

 B. M. p. 65), and Ch. punctulata (t. 25) (Jacare punctu- 

 lata, Gray, Cat. B. 31. p. 65), which seem to differ from the 

 former in the head being narrower and more tapering. I 

 have seen no specimens agreeing with these figures ; but 

 they look very like varieties of the above. At the same 

 time some of our specimens appear to have a more at- 

 tenuated snout than others ; but when you apply the cal- 

 lipers to the nose and to the other parts of the head, the 

 absolute proportions of the parts are very nearly the same. 

 A stuffed specimen from the Argentine Republic mea- 

 sures 6 feet 9 inches long ; the head from the occiput is 10|, 

 and the nose from the ridge 6| inches. In another, from 

 the Zoological Society's Gardens, 5 feet 10 inches long, the 

 head from the occiput is 10 inches, the nose from the ridge 

 61 inches long. A series of young specimens in spirits are 

 pale brown ; the back and tail with narrow brown cross 

 bands, those on the back sometimes broken into square 

 spots ; the cheek and outside of lower jaw pale yellow, 

 without spots ; the sides of the nuchal disk dark-coloured. 



Alligator lacordairei, Prudh. de Borre, Bidl. Ac. Belg. 

 xxviii. 1869, p. 109, t. . 



Hab. British Honduras (Prudhomme). 



From a young specimen in the Museum of Brussels, and 

 very difficult to determine from his figure. He considers 

 it nearest to Alligator (Jacaretinga) punctulatus, Spix ; but 

 it is too young to determine. 



7. Jacare hirticollis. (Rough -necked Jacare.) B.M. 



The scales on the sides of the neck rough, spinulose, 

 pale yellow ; back and tail brown, cross-barred ; cheek and 

 sides of the lower jaw yellow, not spotted. 



Hab. Demerara (Brit. Mus.). 



I may observe that, characteristic as are the figures of 

 Dr. Natterer's paper, none of them exactly agrees in mea- 

 surements with the specimens in the British Museum. 



In some specimens of the Jacare the first and sometimes 

 even the second cervical scutella have two keels, in others 

 only one ; but this is no specific distinction ; it is not rare 



to find species with two keels on one side of the neck and 

 only one on the other. 



Mr. Cope describes the genus Perosuchus, and thus cha- 

 racterizes it : " Toes 5-4, with claws 2-3 ; no osseous nasal 

 septum or bony eyelid; belly protected by a series of 

 osseous plates as well as the back." 



Perosuchus fuscus, Cope (from New Granada), Proc. Acid. 

 Nat. Sci. Phihd. 1868, p. 203. 



I do not see how this differs from Jacare. 



2. CAIMAN. 



Head high, flattened on the sides, angulated above. I )r- 

 bits without any ridges. The eyelids smooth, strengthened 

 with a large, single, internal bony plate. The dorsal and 

 ventral scutella bony, articulated together, forming a dorsal 

 and ventral shield; the gular and lateral ventral plates 

 keeled, the abdominal ones smooth ; the cervical scutella 

 four or five pairs, with sometimes one or a pair interposed 

 between the second and third pairs. 



Skull with the superior temporal fossa? obliterated, the 

 circumjacent bones uniting ; the eyelid with a single large 

 bony plate covering the whole upper surface ; vomer not 

 apparent on the palate. 



Caiman, Gray, Cat. Tort. SfC. B.M. p. 66, 1844; Ann. $ 

 Mag.N.H. 1862, x. p. 331); Trans. Zool. Soc. 1869, 

 vi. p. 166. 



Huxley, Proc. Linn. Soc. iv. p. 3. 



This genus has been divided into two species— one having 

 the cervical shields two, and the other four in a cross series ; 

 in all the latter there are two in a cross series, with one or 

 two interpolated between the other shields. 



I have seen no specimen which agrees in the nuchal 

 shields with either of the figures in Cuvier, Oss. Foss., 

 though our two species agree in other respects with his 

 figures ; and how such species with distinct organic cha- 

 racters could be regarded as varieties I am unable to learn. 



I cannot conceive what induced M. Cuvier in his ' Essay ' 

 to consider the two South-American Alligators with bony 

 eyelids varieties ; for he justly observes, " The Crocodile of 

 St. Domingo is not more distinct from the Crocodile of the 

 Nile than these two varieties are from each other." 



In the Latin synopsis of the species, which is appended 

 to the paper, they are regarded as distinct, and the second 

 one is called C. trigonatus. Yet MM. Dumeril and Bibron 

 in their work persist in following Cuvier's first idea of their 

 being only varieties, and in regarding Adanson's specimens 



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