﻿31 2 ARTHRODIRA. 



Vetensk.-Akad. Handl. vol. xx. no. 9 (1884), p. 5, pi. ii. fig. 6. — 

 Lower Devonian ; Dickson Bay, Spitzbergen. [Royal State Museum, 

 Stockholm.] 



The hinder portion of the head evidently of one of the Coccosteidao, 

 from the Devonian of the Government of Orel, Russia, has also been 

 described under the name of Siphonodus panderi, G. Fischer do 

 Waldheim, Bull. Soc. Imp. Nat. Moscou, vol. xxv. (1852), pt. i. 

 p. 175, pi. iii. figs. 1-3. In this specimen, the ossified parachordal 

 cartilage is seen, with the tubular canal originally occupied by the 

 anterior extremity of the nofcochord. 



The singular mandibular rami, described as follows, may also 

 pertain to this family : — 



Diplognathus mirabilis, J. S. Newberry, Ann. New York Acad. 

 Sci. vol. i. (1878), p. 188, and Trans. New York Acad. 

 Sci. vol. v. (1885), p. 27, and Palseoz. Fishes N. America 

 (Hon. U.S. Geol. Surv. no. xvi. 1889), p. 159, pi. xi. 

 figs. 1-4, pi. xii. figs. 1-3. — Cleveland Shale ; Lorain Co., 

 Ohio. [Columbia College, New York.] 



Family ASTEROSTEIDjE. 



An imperfectly known family, as yet incompletely definable. 

 Nasal openings large and mesially placed, scarcely, if at all, in 

 advance of the orbits. 



Genus ASTEROSTSUS, Newberry. 

 [Rep. Geol. Surv. Ohio, vol. ii. pt. ii. 1875, p. 35.] 



A genus comprising species of small size, known only by the 

 cranial shield. Head long and narrow, flattened, having the con- 

 stituent elements fused in the adult ; orbits placed far forwards and 

 forming broad notches, between which is a pair of large, oval nasal 

 openings ; a pineal foramen somewhat more posteriorly. Cranial 

 roof ornamented with large, rounded, stellate tubercles, very irre- 

 gular in size and arrangement. 



This diagnosis is based upon a personal examination of the 

 specimens in the Columbia College, New York, and the American 



