408 



MEMOIRS OF THE CARNEGIE MUSEUM. 



fringed with fulcra. Anal fin with seven rays; pelvics midway between the anal and 

 the pectoral pair; the latter comprising about twelve much elongated rays. Scales 

 thin, with five or six very long and sharp denticulations along the posterior border, 

 and covered with exceedingly delicate horizontal striations on the inner surface. 

 Teeth minute. 



The holotype of this species is shown from the left lateral aspect in Plate LXVIII, 

 Fig. 2, somewhat larger than natural size. A portion of the squamation having 

 adhered to the opposite half of the containing matrix, the scales are seen from 

 the inner side in the only part of the specimen which is now preserved. They are 

 semitranslucent, and the remarkably strong denticulations are visible through the 

 thickness of the overlapping series. 



Family PYCNODONTID^. 



Genus Mesodon Wagner. 



25. Mesodon macropterus (Agassiz). (Plate LXI, figs. 1 and 2.) 



(For synonymy cf. A. S. Woodward, Cat. Foss. Fishes Brit. Mus., Pt. Ill, p. 199.) 



This species is represented in the collection of the Carnegie Museum by two 



relatively large-sized individuals (Cat. Nos. 4733, 4891), which measure about 



22 cm. in total length, but are slightly injured in the region of the head; also by a 



pmx 



Fig. 3. Mesodon macropterus. (After A. S. Woodward, "Outlines of Vertebrate Paleontology," p. 105, 



1898, fig. 74.) 



