ART. XXXV -ON THE GENUS ERISICHTIIE. 



By E. D. Cope. 



ErisicWie is a genus of fishes which was described by the writer in 

 1873, and subsequently referred to the Saurodontidce. In the Final lleporC 

 of the United States Geological Survey of the Territories,* the typical 

 species, E. nitida, was again described, and also figured, so far as the 

 material permitted, and the existence of a second species, E. angulata^j 

 was pointed out. Subsequent accumulation of material enables me to 

 add to the knowledge of the structure of the genus and to increase the 

 number of known species. 



The E. nitida Cope was originally represented by a few portions of the 

 skull; among other pieces, the premaxillary and dentary bones being 

 present. The latter element was correctly determined, but the premax- 

 illary was called maxillary in my description. A fine specimen of this 

 species, obtained the present season from the Niobrara Cretaceous of 

 Kansas, by Charles H. Sternberg, includes the greater part of the cra- 

 nium. From this and other specimens I discover that the anterior por- 

 tion of the skull, probably the ethmoid bone, is produced into a long 

 beak, in general form similar to the sword-like snout of the Sword-fishes 

 of modern seas. I had already been in receipt of fragments of these 

 beaks, associated with loose teeth of the genus Erisichthe, but it was 

 Prof. B. F. Mudge who first pointed out that both belong to one and 

 the same genus.l The specimen above mentioned includes also the 

 maxillary bones, so that their true character is now clear. A remark- 

 able feature of the genus is displayed in the mandibles. E ich of these 

 is compound in the region usually composed of the simple dentary bone. 

 It there consists of three parallel elements, an internal and an external 

 embracing a median element. The inner bears a baud of teeth en brosse 

 on its inner and superior aspect, and the external a few teeth of similar 

 character on its superior edge. The large lancet shaped teeth are borne 

 by the middle element, excepting some of the largest near thesyniphysis. 

 Two of these on the inner side of the ramus originate in the internal 

 bone. The maxillary bone forms the greater part of the arcade of the 

 mouth, and ha3 no superior articulation with the facial part of the skull. 

 It is attached by a simple sutural articulation with the premaxillary, so 



* Vol. ii, 1875, p. 217, pi. xlviii, tigs. 3-8. 



t Porthetts aiujnldtus, Geolog. Survey N. Caioliua, by \V. C. Kerr, p. 152. 



X Bulletiu U. S. Geol. Survey Terrs. 



821 

 6 BULL 



