704 DR RAMSAY H. TRAQUAIR'S DESCRIPTION OF 



become smaller posteriorly, but all are expanded at their extremities, these form- 

 ing apparently a continuous line, to which the fin rays are articulated. 



In the tail may be seen, in the same specimen, two sets of ossicles, an upper 

 supporting the large azygos scales of the body prolongation, these being probably 

 of the nature of neurapophyses ; and a lower set supporting the rays of the 

 caudal fin, and which may be regarded as the interspinous bones, or those in 

 conjunction with the inferior spinous processes of the caudal vertebrse. These 

 caudal interspinous bones are stout anteriorly, but become very small behind, 

 where they assume a distinct hour-glass shape, being expanded at each extremity, 

 and narrow in the middle, and where it may also be beautifully seen how each 

 interspinous bone supports several fin rays. This must necessarily be the case 

 in all the fins, seeing that the number of rays very considerably exceeds that of 

 their supporting ossicles. 



Head. — Figs. 2, 3, and 4 represent various views of the head of the specimen 

 already alluded to in the description of the interspinous bones and of the caudal 

 rays. 



Fi«\ 2 is a profile view of the head, in which the eye is at once struck by the 

 strength of the jaws, the extent of the gape, the very anterior position of the 

 orbit, and the projection of the snout. 



Fig. 3 is a view of the bones on the top of the cranium, and fig. 4 represents 

 the snout seen from the front. 



Referring to fig. 2, which in fact represents a cast of the inner surface of the 

 cranial buckler, the bone having splintered off along with the matrix, leaving the 

 sutures standing up as prominent lines, the lines radiating from the ossific centres 

 beino* also well displayed, we find that some of the numerous bones exposed 

 are easily enough recognised. Posteriorly, we have the parietals (7) very short, 

 and nearly square shaped, articulating with each other in the middle line, as in 

 Lejridosteus and Polypteras, there being no supraoccipital interposed as in most 

 Telostei. In advance of them, and forming a large part of the vault of the 

 cranium, we have the frontals (11). From the frontals we pass on to the single 

 nasal bone (15), which forms the prominent point of the snout above the mouth. 

 Opposite this prominence the nasal bone is notched on each side for the olfactory 

 opening and from the prominence itself pass beautifully radiating lines over the 

 whole surface of the bone. On each side of the nasal bone is situated the pre- 

 frontal (14, figs. 3 and 4,) which completes the olfactory notch of the former bone 

 into a nearly round opening, It articulates internally with the nasal, below with 

 the intermaxillary, and behind with the bone to be next described as post-frontal. 

 Externally, it forms the anterior part of the orbital margin of the cranial shield. 



The bones (12) behind the pre-frontals, and forming the posterior part of the 

 orbital maro-in of the cranial shield, I can imagine to be nothing else than the 

 post-frontals, though they are certainly situated rather far forwards. They 



