398 Bulletin American Museum of Natural History. [Vol. XIX, 



PRISTID^. 



Sclerorhynchus Woodward. 

 Plate XXIV, Figure i. 

 Woodward (A. S.), Cat. Foss. Fishes, I, 1889, p. 76. 



In the collection there is found the greater portion of the 

 trunk of a sawfish, No. 4502 (3686). To what species this 

 may belong cannot now be determined. The shagreen gran- 

 ules of this trunk are small, and are furnished with two or 

 three longitudinal ridges and intervening furrows. In two of 

 the species of this genus here described, 5. sentus and S. 

 hiram, no shagreen is satisfactorily observable behind the 

 rostrum, while in 5. solomonis the shagreen appears to be 

 wholly smooth. Hence, while it is improbable that the trunk 

 belongs to the latter-mentioned species, it cannot be con- 

 nected with either of the others. The shagreen of the trunk 

 resembles that of Pristis perrotteti. 



The structure of the species of Sclerorhynchus here de- 

 scribed, especially the evidence that the gill-slits opened on 

 the lower side of the head, shows that the genus is to be re- 

 ferred to the Pristidas. 



To whatever species this trunk may belong, it gives us a 

 clear idea of the form of the body of the Upper Cretaceous 

 sawfishes. And this form is remarkably like that of Pristis. 

 As is to be observed from the figure (PL xxiv. Fig. i), the 

 body is long and slender. The portion at hand begins ap- 

 parently near the base of the pectoral fin and ceases about 

 the root of the caudal fin. The length of the part is 280 mm. 

 It is not certain that any portion of the pectoral fin is seen. 

 The depth of the body anteriorly is 47 mm. Both the dorsal 

 fins and one ventral are presented. All are triangular in form 

 and approximately of the same length. The base of the first 

 dorsal is 36 mm.; the height, 21 mm. The apparent height 

 of the ventral fin is 14 mm. At the base of each fin are seen 

 impressions of the cartilaginous supports of the fin. At the 

 base of the first dorsal there are at least 16 rays; at the base 

 of the second dorsal, a somewhat greater number; at the 

 base of the anal, at least a dozen. 



