Page:Proceedings of the Royal Society of London Vol 1.djvu/68

Rh with in other large lakes of the neighbourhood, although these be known to communicate with the former by subterraneous channels. The specimens which have as yet reached either the public or private collections are so few, that all the descriptions hitherto given by Laurenti, Scopoli, Herman, Schneider, and Gmelin, have been found equally defective and erroneous, especially as to the anatomical con- struction, which, indeed, those able naturalists have scarcely had opportunities of investigating. This defect probably gave rise to a difference of opinion concerning the class to which this animal is to be annumerated; some considering it as a species arrived at its degree of perfection, while others maintain that it is the larva of some kind of lizard hitherto unknown.

The principal object of this paper is to offer so circumstantial a description of the different parts of this animal as to enable physio- logists to determine the point hitherto undecided. The specimen from which this description was taken measured about thirteen inches in length, and one inch in diameter; the fore part of the head was flat and narrow, somewhat resembling the bill of a duck: the upper lip projected considerably beyond the lower one. No external traces of nostrils, ears or eyes could be discovered. Of the latter, however, some indications are thought to have been perceived on a living spe- cimen. On each side of the occiput was an opening, like those of fishes; and over them certain branchial appendages, similar to those in tadpoles and other larvæ of amphibious animals; whence probably arose the difference of opinions concerning the nature of this animal. From the description here given, we are to infer, that the construc- tion of these parts, when carefully examined, differs materially from those as well of fishes as of tadpoles or other larvæ.

The body is round, equally thick throughout between the fore and hind feet: the fore feet are about one inch long, each having three toes without nails, the hind feet about two lines shorter with only two toes: behind the latter the body grows narrower, and terminates in the tail, which is compressed on the sides, and ends nearly in a point. The skin is coriaceous; but looking at it with a magnifier, it exhibits a number of minute glands underneath the epidermis, similar to those in water-lizards, &c. Its colour when alive is a light red; but when kept a while in spirits, it becomes of a dusky brown.-A detailed account is also given of the muscular fibres under the skin.

Upon opening the body by a longitudinal section, the whole ca- vity was found almost filled by the liver, extending from the thorax down to the pelvis, so as to cover the greatest part of the other viscera. The heart consists of a single ventricle, and an auricle as large as the ventricle. The situations, dimensions, and structure of these, as well as of the stomach, intestines, gall-bladder, spleen, kidneys, pancreas, &c., are minutely described: and as it was found to have something particular in its formation, the author dwells somewhat more at large on the air-bladder, or pneumatic apparatus, which he met with in the thorax, immediately below the heart. This he found to he a simple bag, without any cellular structure, as in the