268 Messrs, Hancock & Atthey on Reptile- and Fish-Remains 



was only seven times the length of the cranium, which is about 

 the proportion of these parts in Keraterpeton Galvani^ a com- 

 paratively short species, then Pteroplax must have been eight 

 or nine feet long. 



This new genus, though it seems, as above stated, to be 

 nearly related to Loxomma, resembles not a little, in the 

 general form of the skull, as far as it can be determined, 

 Dasyceps Bucklandi^ . The concavity of the occipital margin 

 and the two lateral cornua are very similar in both species ; 

 but in the latter these processes or horns are more robust, 

 and do not look so spine-like as in Pteroplax cormda. The 

 proportions and forms of the component bones, too, are very 

 different,- and the parietal foramen in Dasyceps is much nearer 

 the occipital margin, as are also the orbits, which are likewise 

 very much smaller. The resemblance, also, of these cranial 

 bones to those of Keraterpeton cannot be overlooked, so far 

 as they can be compared. The general form of the crown 

 of the head, with the narrow projecting frontals and concave 

 occipital margin, together with the " postero-internal cornua," 

 are all remarkably alike in the two foi-ms ; but, from the defi- 

 ciency of surface-sculptm-e in that animal, and its compara- 

 tive smallnes, it would seem that they cannot be considered 

 congeneric. 



Four left premaxillaries have been obtained; and all of them 

 have a portion of the nasal bone attached, as well as several 

 teeth more or less perfect. The premaxillary is about two 

 and a half inches long, and upwards of half an inch wide ; it 

 is arched most strongly towards the anterior symphysis, which 

 is oblique and coextensive with the width of the bone ; be- 

 hind, it is prolonged, the articular portion being wedge-shaped; 

 the surface is strongly sculptured into elevated anastomosing 

 ridges and depressions; and they all exhibit two strong, wide, 

 round grooves on the external surface, one of which passes 

 from the front, the other from behind, converging and meet- 

 ing at nearly a right angle, close to the alveolar margin. 

 These grooves are similar to what have been denominated 

 mucus-grooves in the Labyrinthodonts, and are exceedingly 

 like those figured and described by Prof. Owen on the muzzle 

 of Labyrinthodon lep)tognathus'\. And in this instance they 

 seem to indicate the boundary of the nasal bone, which is ap- 

 parently of a lozenge-form, probably somewhat prolonged 

 backwards. Half the circumference of an external nasal ori- 

 fice is distinctly perceptible in two of the specimens ; it is cir- 

 cular, and about one-quarter of an inch in diameter : the tAvo 



* Memoirs Geol. Survey, 18-59, p. 52. 



t Trans, Geol, Soc. ser. 2. vol. vi. p, 417, pi. 43. %. 1, 



