REMAINS OF REPTILES AND FISHES. 87 



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 premaxillary bones, which were wanting in Dr. Young's 

 specimens, are present in some of ours ; 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 uncommon 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 premaxillary bone is unusually long. The maxilla is 

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

 considerably behind. The mandibles are long, narrov/ bones, 

 with the margins nearly parallel and the distal extremity rounded. 

 The surface of all these bones is rugose, with irregular reticu- 

 lated ridges, or wrinkles and punctures. 



All the bones of the jaws frequently occur detached. A large 

 series of such have been procured, many of which are associated 

 with the scales of the fish. The anterior laniary teeth are nearly 

 always present in both the praemaxillEe and mandibles ; but the 

 additional large teeth of the latter are seldom present. In four 

 or five instances, however, they are distinctly displayed ; and in 

 one specimen there are five laniary teeth, including the anterior 

 one. 



In the detached state the form of these bones can be well ob- 

 served. The maxillaries are usually -A-ths of an inch long, and 

 about ^o-ths of an inch wide at the broadest part. They are 

 flat thin bones, produced and pointed in front, and widened i-a- 

 ther suddenly behind, as already stated ; the alveolar border is 

 nearly straight ; the upper border in front is parallel with the 

 alveolar border for some little distance backwards ; it then sud- 

 denly ascends to the posterior margin, which slopes backAvards 

 and downwards. There is, at a little distance from the ante- 

 rior extremity, a well-developed narrow articular process, which 



