350 Messrs. Hancock & Atthey on Rejytile- and Fish-Remains 



In all respects our specimens agree well with Dr. Young's 

 description of this species in the ' Journ. Geol. Soc' {loc. 

 cit.). The scales are usually well preserved ; all the fins, as 

 well as the tail, can be determined; and the gill-opercles, 

 mandibles, and upper jaws, in a more or less entire state, with 

 the teeth attached, are all displayed. 



The scales vary, of course, greatly in size ; on the smallest 

 fish they cannot be more than a quarter of an inch long, while 

 large detached scales measm-e an inch in length. They are 

 all, however, so perfectly similar that it is impossible to deny 

 their specific identity. The coarseness of the surface-sculp- 

 ture and the thickness of the scale vary, as might be expected, 

 with its size ; but no other difference can be detected. It is 

 therefore only left us to follow the prudent caution of Dr. 

 Young, and to wait for further information before doing any- 

 thing so rash as to divide specifically the thin and delicate 

 from the thick and comparatively coarse scales. There is one 

 character, however, which seems to have escaped the notice of 

 this paleontologist, and which is pretty distinct in one or two 

 of our examj^les. The dorsal and ventral fins are protected in 

 front by a series of thick enamelled scales, which are brilliantly 

 glossy and minutely punctured, not at all like the body-scales, 

 but similar to those in front of the fins, in Megalichthys. The 

 first or proximal scale is very stout, if not a solid cylinder, and 

 is three-quarters of an inch long ; it looks almost like the base 

 of a spine, but is probably composed of two lateral plates. 

 This is succeeded by a double longitudinal series of elongated 

 rectangular pieces, which extend apparently almost to the 

 distal margin of the fin. 



The premaxiliary bones, which were wanting in Dr. Young's 

 specimens, are present in some of om'S ; and they, as well as 

 the mandibles, have a large, slightly curved laniary tooth at 

 the distal extremity. This is succeeded by a series of numerous 

 small conical teeth, of the same size and character as those of 

 the maxilla. These, as well as the small mandibular teeth, 

 are placed at pretty regular intervals, though it is not uncom- 

 mon to observe two or three pressed close together. Traces of 

 two or three additional laniary teeth can be observed in the 

 mandibles, situated on a line a little within the row of smaller 

 teeth. 



The premaxiliary bone is unusually long ; the maxilla is 

 shorter than the former, and is narrow in front and expanded 

 considerably behind. The mandibles are long, narrow bones, 

 with the margins nearly parallel and the distal extremity 

 rounded. The surface of all these bones is rugose, with irre- 

 gular reticulated ridges or wrinkles and pimctiires. 



