ICHTHTODORULITES 
151 
Pier 
11 . 
Traquair.) 
Harpaeanthus firnbriatus (Stock).—M. Carb. Limest., Gilmeiton. (After 
V. Dermal defences of doubtful position. 
Genus EDESTUS, Leidy. 
► 
■J' 
\ 
% 
.V* 
7 ^ 
crc. 
Proc. Acad. Nat. Sci. Philad. vol. vii. 1856, p. 414.] ^ ‘ 'f - 
Syn. Protopirata, H. Trautschold, Zeitscbr. deutsch. geol. Gesell.vol. xl, 
1888, p. 753. /j^ . <c6 . 
Spine broad, laterally compressed, elongated and gently arched ; 
convex margin armed with a series of large broad denticles, serrated, 
and enveloped in ganoine : sides of the spine destitute of surface- 
ornament and ganoine, being only marked by oblique transverse 
sulci, each arising from the point of separation of two denticles, and 
often implying the complete division of the spine into a series of 
segments, easily detached one from another ; concave margin with¬ 
out denticles. jNo distinct base of insertion. 
Originally regarded as portions of the jaw of a fish by J. Leidy 1 and 
Newberry 2 , and compared with the rostral prolongation of Pristis by 
L. Agassiz 3 , these remarkable fossils were first suspected to be Elas- 
1 Proc. Acad. Pat. Sci. Philad. vol. vii. (1856), p. 414. 
2 Pal. Illinois, vol. ii. (1866), p. 84. 
3 Proc. Amer. Assoc. Adv. Sci. 1855 (1856), p. 229. 
