550 Prof. W. N. Parker. Chi the Anatomy and [May 28, 



accident. The tail is almost certainly not primarily diphycercal, 

 and shows signs of a possible origin from a heterocercal form. 



The epidermis on the whole most nearly resembles that of Perenni- 

 branchiate Amphibians, and gives rise to simple multicellular glands 

 (which are most numerous on the snout), as well as to very numerous 

 closely-packed goblet-cells, which produce the gluey secretion as well 

 as the main substance of the capsule which surrounds the animal during 

 the torpid state. The epidermis forms a regular and continuous 

 layer over the derma, in which the cycloid imbricating scales are 

 imbedded. Pigment cells are present in both layers of the integu- 

 ment, and the derma encloses nests of leucocytes here and there, 

 small cells, apparently migratory leucocytes, being seen in places 

 amongst the ordinary epidermic cells. 



Integumentary sense organs, similar to those of Fishes and larval 

 Amphibians, are present not only on the head and lateral line, but 

 in various other regions of the trunk also ; they are most numerous 

 on the head. In young animals they are all superficial, and do not 

 project below the general level of the epidermis, and this condition 

 is retained in those situated on the trunk. On the head, the 

 epidermis becomes involuted along certain lines to form grooves, 

 which then become converted into sub-epidermic tubes, in which the 

 sensory organs are situated, and which communicate with the exterior 

 by an aperture at one end. The relations of the sensory organs of 

 the trunk are therefore similar to those seen in young stages of Fishes 

 and in Amphibian larvae, while in the case of the head, they resemble 

 those which are typical for adult Fishes. End-buds, similar in 

 structure to the taste-bads of Fishes and Amphibians, are present on 

 the tongue and oral epithelium, but are absent on the lips, and, as in 

 Amphibians, do not occur on the surface of the body. 



As regards its general structure, the olfactory organ most nearly 

 resembles that of Elasmobranchs, but the presence of posterior nostrils 

 raises it to a higher level. The position of the anterior nostrils 

 beneath the upper lip is probably to be accounted for as an adapta- 

 tion in connexion with the torpid state (vide infra). The space 

 between the eyeball and its muscles and the orbit is filled with a 

 delicate connective tissue; there are no orbital glands or eyelids. 

 Four straight and two oblique muscles are present. The cornea is 

 continuous with the derma on the one hand, and the sclerotic on the 

 other ; the latter is fibrous in young animals, and islands of cartilage 

 first appear at the points of insertion of eye-muscles, and then 

 gradually extend so as to chondrify the whole sclerotic. The eye 

 resembles that of Amphibians ; a processus falciformis and campa- 

 nula Halleri are absent, and no ciliary muscles were observed, though 

 possibly present ; almost all the pigment of the eye is ectodermic. 



No specialised glands are present in connexion with the greatly 



