Zoological Collections* 335 



Length of the hand - - _ . 14. 



Breadth of ditto - -4, 



Length of the longest nail - - - - •?.', 



Length of that portion of the tail which is free, and curved 



beneath the body - - - _ 12 



The shell which covers the body is of a consistence somewhat more 

 dense and inflexible than sole leather of equal thickness. It is composed 

 of a series of plates of a square, rhomboidal, or cubical form ; each row 

 separated by an epidermal or membranous production, which is reflected 

 above and beneath over the plates; the rows include from fifteen to twen- 

 ty-two plates ; the shell being broadest at its posterior half, extending 

 about one half round the body ; this covering is loose throughout, except- 

 ing along the spine of the back and top of the head ; being attached to 

 the back immediately above the spine, by a loose cuticular production, 

 and by two remarkably bony processes (to be described hereafter) on the 

 top of the os frontis, by means of two large plates, which are nearly in- 

 corporated with the bone beneath ; but for this attachment, and the tail 

 being firmly curved beneath the belly, the covering would be very easily 

 detached. The number of rows of plates on the back, counting from the 

 vertex, (where they commence) is twenty-four ; at the twenty-fourth the 

 shell curves suddenly downwards, so as to form a right angle with the 

 body ; this truncated surface is composed of plates nearly similar to those 

 of the back ; they are disposed in semicircular rows, five in number : the 

 lower margin, somewhat elliptical, presents a notch in its centre, in which 

 is attached the free portion of tail, which makes an abrupt curvature, and 

 runs beneath the belly parallel to the axis of the body ; the free portion of 

 tail consists of fourteen caudal vertebra;, surrounded by as many plates, 

 similar to those of the body ; the extremity of the toil being depressed, 

 so as to form a paddle ; the rest of the tail compressed. The caudal ver- 

 tebrae extend up to the top of the back, beneath the truncated surface, 

 where the sacrum is bent to meet the tail. The superior semicircular mar- 

 gin of the truncated surface, together with the lateral margins of the shell, 

 are beautifully fringed with silky hair. 



Head: posterior half, broad, anterior half, before the eyes, tapering ; 

 the occiput is covered by the five first rows of the back plates, with which 

 they are continuous ; the occiput not distinguishable externally. The an- 

 terior half of the top of the head is covered, first, by a row of large plates, 

 five in number, which are firmly attached to the bone beneath ; particu- 

 larly the two outer ; — secondly, by a smaller row, six in number, anterior 

 to which, that is to say, the top of the snout, is covered with smaller 

 plates irregularly disposed. 



External ear, consists of a circular, somewhat patulous opening, directly 

 posterior to the eye, surrounded with an elevated margin ; and communi- 

 cating with a bony canal, to be more fully described hereafter. Eye, mi- 

 nute, totally black ; and, like the ear, nearly hidden by long silky hair 

 Mouth, the rictus small. Nn$e, the extremity of the snout is furnished 



