86 Dr. H. Riley on the Squaloraia. 



The anterior piece on the right side, is evidently continuous with the cranium ; 

 the middle one on the left presents the appearance of a joint : but we do not 

 recollect to have seen jointed feelers. In the common Skate are two small 

 bones in this position, and in tlie Squalus Squatina, the only specimen of 

 a Squale in our possession, are three large bones or pieces extending from 

 the upper to the lower jaw, and placed considerably anterior to the temporo- 

 maxillary articulation. Two of these pieces are articulated with the upper jaw 

 at one end, and by the other with the third piece, which extends itself to the 

 lower jaw. 



Although these analogies are very imperfect, we cannot help thinking that 

 if more extensive means of comparison were in our possession, we should find 

 that they belonged to the latter category. 



Behind the cranium in the cervical region, are several detached elongated 

 pieces, which we are inclined to. consider as remains of the branchial appa- 

 ratus ; on the left behind the orbit, is a portion lying at right angles with the 

 vertebral column, another is parallel, a third is to be seen to the right. 



What remains of the vertebral column, is less injured than the other parts. 

 The processes of the vertebrae have disappeared, leaving the bodies which 

 are circular very perfect. They are concave anteriorly as well as posteriorly, 

 as may be seen at the places where they have been fractured. 



This column, or the cycleal elements of it are cylindrical, its transverse 

 diameter seems rather to increase towards the posterior extremity. 



The vertebrae are extremely numerous, and are injured in a few places, 

 which prevents our counting them very accurately. There are about 260 

 in the whole, of which 28 are cervical, counting as far back as the middle 

 of the transverse piece, corresponding to the scapular region; 143 dorsal, 

 counting to the middle of the pelvis ; and the remainder, 90, belong to what 

 remains of the tail. 



Their transverse diameter is six times more than their antero-posterior 

 diameter. 



In the Rays the cervical portion is consolidated inferiorly into one entire piece, — in the Squales it 

 consists of distinct vertebrae; indeed the analogies of fornn in this column with that of the Squales, 

 are much closer than with any other genus with which we are acquainted ; for in the Squales, 

 as in the common Shark for instance, the cycleal elements of the vertebrae or the bodies are quite 

 round. In them the vertebral canal can hardly be said to be formed at the expense of the bodies, 

 which present a very superficial groove only, at their superior surfaces for the reception of the 

 spinal marrow, the canal being principally made up by the epial elements, in other words, by the 

 plates and spinous processes, which in many of this genus are very easily detached. 



This canal is more deeply grooved in the bodies of the vertebrae of the Rays, whilst the plate 

 and spinous processes are in general wider and stronger, and more firmly attached. 



