102 



Peresnibkanchiate A.mpiiibia.- 



- REPTILES. - 



-Peresnidranchiate Amphibia. 



kept in a vessel containing a large quantity of water, 

 or in which the water is frequently changed, it mani- 

 fests hut little disposition to rise to the surface for 

 atmospheric air ; but when the quantity of water is 

 small, or not often changed, it soon finds the air in the 

 water insufficient for its purposes, when it ascends to 

 the surface, takes a mouthful of air, and sinks again 

 with it to the bottom." 



In the second family of this order, the Sirenid^, 

 we have only space to mention particularly one species. 

 Tills is well known by the name of the Mud-eel. 



THE MUD-EEL or Siren (5(VfjiZacert/n(i) — represented 

 in Plate 4, fig. 1 — is a native of South Carohna and 

 Georgia, and is about nineteen inches in length, and 

 even sometimes reaches two feet, while it measures 

 four or five inches in circumference. In its general 

 form and aspect it bears a great resemblance to an 

 eel, and the surface of the body is very smooth and 

 slimy. The tail is long and compressed, and is mar- 

 gined for several inches both above and below by a 

 narrow, rayless fin, which greatly assists it in moving 

 through the water. It is of a deep blackish-brown 

 colour, rather paler beneath, where it is partially 

 tinged with a bluish hue, with a tinge of violet, and is 

 marked all over with nimierous small white or milky 

 spots. The head is rather small for the size of the 

 animal, is depressed, of a suboval form, and the muzzle 

 is blunt and flattened. The month is not wide, but is 

 covered with tolerably thick lips. The nostrils are 

 small, placed near the anterior angle of the upper jaw, 

 and the eyes are very small, dim, of a blackish colour, 

 and covered with a prolongation of the skin. The 

 gifls, according to the late Mr. James Wilson, to whose 

 memoir we refer tlie reader, consist of tliree fleshy 

 pcdimcles, which increase in size from the first to 

 the last. They are beautifully branched from beneath, 

 and along their lateral and terminal edges ; and these 

 little branches are divided and subdivided into still 

 more minute ramifications. This elegant fringe-work 

 forms tlie true gills, the central and fleshy stalks serv- 

 ing merely as their support. Beneath, and rather in 

 advance of these bodies, are three nearly vertical 

 clefts, through which the water is ejected backwards 

 from tlie inside of the mouth upon the gills, though 

 with a much more languid and less perceptible action 

 than in fishes. The feet are only two in number, the 

 anterior pair ; they are but slightly developed, how- 

 ever, and of little service, if any, in progressive motion. 

 Tliey are in constant motion, as the animal moves from 

 place to place on land, and are folded back when it 

 swims in the water. They are each terminated by 

 four toes, the extremities of which are rather pointed, 

 slightly curved, and terminate in scnii-corueons tips. 



This animal, as its English name indicates, lives chiefly 

 in mud, and, according to Mr. Ilolbrook, is abundant 

 in the rice-fields of Carolina. " It is often thrown 

 out," he says, " in great numbers, at certain seasons, 

 when the ditches are cleaned. Being regarded, how- 

 ever, as venomous by the slaves, they are instantly 

 killed or dreadfully mangled, and loft to serve as food 

 for racoons or for turkey-buzzards, ever on the watch. 

 Sometimes they leave the soft mud in which they 

 commonly burrow and take to the water, in which 

 they swim with great swiftness. Tliey are occasionally 

 taken by persons angling for the common perch of 

 Carolina [Pomotcs vulgaris), with a bait of earth- 

 worms. Sometimes they leave the water entirely, like 

 eels, and are found on dry land ; but whether in search 

 of food, or to rid themselves of parasitic animals, can- 

 not at this moment be ascertained." From its living 

 in muddy places, it was called by the inhabitants the 

 j\lud Icjuana. Its food is generally believed to con- 

 sist of earth-worms, insects, &c. A specimen, which 

 was kept alive in the Zoological Gardens, Regent's 

 Park, in 1841, was supplied with about a dozen and a 

 half of earth-worms daily. This individual was twenty 

 inches long, and as large as the wrist of a stout child of 

 six months old. Another specimen was kept alive by 

 Dr. Patrick Noill, at Canonmills, near Edinburgh, for 

 three or four years, and was made the subject of an 

 elaborate memoir by the late Mr. James Wilson. 

 During the whole of this period no change took place 

 in its gills or lungs. Dr. Garden was the first person 

 who discovered the Siren, and he sent an account of it 

 to Linntens through our countryman John Ellis. These 

 three naturalists, and the celebrated Jolm Hunter, con- 

 sidered it to be a perfect animal, and Linnieus estab- 

 lished a distinct order for it amongst the Amphibia, 

 which he called Meanles. Pallas, Count Lacepede, 

 and some others, considered it only a tadpole of some 

 large species of Salamander ; and the celebrated ana- 

 tomist Camper even went so far as to place it amongst 

 the fishes. Cuvier, however, established most satis- 

 factorily that the Siren was a perfect animal, and a 

 true Amphibian, which respires at will throughout its 

 life, either in the watur by means of branchiae, or in 

 the air by means of lungs. The blood-globules of the 

 Siren were ascertained by Professor Owen to be, like 

 those of the Proteus mentioned above, of a very large 

 size ; and it appears now a well-established fact, that 

 these globules are of a gi'eater relative magnitude in 

 the Perennibranchiate amphibians, or those which have 

 persistent branchial apparatus, than in any other ani- 

 mals of the class to which they belong. 



As we have mentioned, at p. 86, the order Psi;u- 

 DOlCUTllVAS will take its place in the article FisiiiiS. 



END OF REPTILIA 



