Chlamyphorus truncatus. 157 



production, and by two remarkable bony processes (to be de?- 

 scribed hereafter) on the top of the os frontis, by means of two 

 large plates, which are nearly incorporated with the bone be- 

 neath ; bi)t for this attachment, and the tail being firmly curved 

 beneath the belly, the covering would be very easily detached. 

 The number pf 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 semi- 

 circular rows, five in number : the lower margin somewhat ellip- 

 tical, presents a notch in its centre, in which is attached the free 

 portion of tail, which makes an abrupt curvature, and runs be- 

 neath the belly parallel to the axis of the body; the free portion 

 of tail consists of fourteen caudal vertebrae, surrounded by as 

 oaany plates, similar to those of the body ; the extremity of the 

 tail being depressed, so as to form a paddle; the rest of the tail 

 compressed. The caudal vertebrae extend up to the top of the 

 back, beneath the truncated surface, where the sacrum is bent to 

 meet the tail. The superior semicircular margin of the truncated 

 surface, together with the lateral margins of the shell, are beauti- 

 fciUy 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 distir- 

 guishable externally. The anterior 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 ; particularly 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 mar- 

 gin, and communicating with a bony canal, to be more fully de- 

 scribed hereafter. Eye^ minute, totally black ; and, like the ear, 

 nearly hidden by long silky hair. 



Mouthy the rictus small. Nose; the extremity of the saout is 



