CROCODILIDAE 471 



the parents taking no care of them, though they may remain for 

 some weeks in the same locality. In the spring and early 

 summer months, and during the time of incubation, and especially 

 on clovidy days or in the evening, alligators make a great noise ; 

 their croak is not unlike that of the- bullfrog, but louder and 

 less prolonged. On the approach of winter they select holes in 

 the ground, where they remain torpid until spring. In this 

 state of hibernation many are dug out by the negroes, who 

 esteem the tail as an article of food. 



A. sinensis. — The first intimation of the existence of a 

 Crocodilian in the Yang-tse-kiang was made by Swinhoe in 

 1870, but it was not until nine years later that PauveP 

 described the creature as A. sinensis. The same gentleman gave 

 also an exhaustive account of the former records of this species 

 in Chinese literature. According to Boulenger its nearest ally 

 is A. mississippiensis, but it approaches the Caimans by the 

 presence of ossifications in the ventral shields, which ossifications 

 are, however, wide apart from each other. There are three pairs 

 of large nuchal scutes in contact in the median line, besides 

 smaller scutes in front of the nuchals and behind the occiput. 

 The dorsal shield contains six rows of larger scutes. The fingers 

 are not webbed. The general colour is greenish black above, 

 speckled with yellow ; greyish below. Total length only about 

 six feet. 



Caiman. — The five species of this genus, confined to Central 

 America or to the East Andesian parts of South America, 

 resemble the Alligators in most features, but differ from them in 

 the following points. The nasals, although bordering the nasal 

 groove, do not form a bony nasal septum. The supratemporal 

 fossae are very small ; or closed up, as in C. trigonatus and C. 

 palpelrosus of Guiana. The ventral armour is composed of over- 

 lapping bony scutes, each of which is formed of two parts united 

 by a suture. 



C. sclerops has the widest distribution, from Southern Mexico 

 to the northern half of Argentina. The upper eyelid is rugose, 

 although only incompletely ossified, and is often more or less 

 produced into a small horn. C. niger has flat upper eyelids. 



According to Bates, Caimans exist in myriads in the waters 

 of the Upper Amazons. One species, C. trigonatus, the Jacari- 

 1 /. China Asiat. Soc. xiii. 1879, pp. 1-36, with Figs. 



