KEMAINS OF REPTILES AND FISHES. 107 



that the latter is. Be this as it may, both kinds of scales are 

 found scattered in the vicinity of the head and spine. 



AcANTHODOPSis Egertoni, n. sp. 



A crushed head, with the pectoral spines attached, a detached 

 jaw or two, a few separate spines, and some scattered scales are 

 all the remains that have occurred of the large species alluded 

 to. The head, which could not have been less than 2J inches 

 long, has one of the mandibular rami well displayed, with the 

 teeth attached ; but they are, unfortunately, in a very imperfect 

 state. The ramus is very similar in character to that of A. 

 Wardi ; but the dentigerous bone does not appear to be striated ; 

 the styliform process is not much arcuated at the proximal ex- 

 tremity, and tapers gradually to the anterior point. The teeth 

 are arranged in the same manner as in the smaller species, that 

 is, with the larger in the centre, and smaller at the extremities 

 of the jaw; with the aid of a detached mandible we are able to 

 ascertain that there are seven or eight in each ramus ; they are 

 not nearly so wide at the base as in the previous species, and 

 they are more regularly and finely striated. Some of the bones 

 of the head are finely and regularly tuberculated ; these are pro- 

 bably the orbital plates. The similar plates of the other species 

 appear to be irregularly granular. 



The spines attached to the head are upwards of 2^ inches 

 long, though they are not entire ; but the largest detached spe- 

 cimen in our possession is quite an inch longer, though in it, 

 too, the point is broken. This must have been longer than the 

 largest mentioned by Sir P. Egerton ; it is upwards of Jth of an 

 inch broad, and is flat and curved like the others, resembling 

 the blade of a scimitar ; towards the base the inner margin is 

 thickened and angulated, and a depressed line or groove extends 

 from end to end a little within the anterior or arched margin ; 

 a few fine longitudinal lines are seen near to and almost parallel 

 with the opposite margin ; the point appears to be rounded, but 

 is not quite perfect in any of our specimens. 



The scales which are found associated with the head and spines 



