CCELACAXTHIDm. 
399 
Superficial ornament of irregular striae; fin- 
rays articulated in-distal half; supple¬ 
mentary caudal much elongated. 
No parafrontal pits; superficial ornament of 
irregular striae and tubercles; fin-rays 
articulated for a long extent distally ; 
supplementary caudal stout. 
Parafrontal and suborbital pits for enlarged 
mucus-follicles ; otherwise resembling 
TJndina . 
No parafrontal pits; superficial ornament of 
sparse tubercles, spinous on the scales ; 
supplementary caudal stout. 
B. Fin-rays long and slender, articulated only 
for a short space distally ; supplementary 
caudal fin apparently rudimentary or 
absent. 
Parafrontals with pits for enlarged mucus- 
follicles ; scale-ornament consisting of a 
prominent median spinous tubercle, with 
smaller tubercles above and below .... 
No parafrontal pits ; superficial ornament of 
spinous tubercles . 
Dipl nr us (p. 409). 
TJndina (p. 409). 
Libys (p. 413). 
Coccoderma (p. 415). 
Ueptanema (p. 415). 
Macropoma (p. 416). 
Of the genera thus enumerated, those named Graphiurus, 
Diplurus , and Coccoderma seem least entitled to distinction, being 
separated from TJndina (so far as known) only by characters of slight 
importance. 
Genus CCELACANTHUS, Agassiz. 
[Poiss. Foss., Feuill. 1836, p. 83, and vol. ii. pt. ii. 1844, p. 170.] 
Syn. Hoplopygus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 1844, p. 178. 
Conchiopsis, E. D. Cope, Proc. Acad. Nat. Sci. Philad. 1873, 
p. 341. 
Rhabdoderma , 0. M. Reis, Palseontographica, vol. xxxv. 1888, 
p. 71. 
The typical genus. Teeth absent on the margin of the jaws, but 
a few hollow, conical teeth within. Supplementary caudal fin 
prominent; the rays of all the fins long and slender, unjointed for 
a considerable length proximally, closely articulated, but without 
expansion, distally ; denticles absent upon all the rays. External 
bones and scales superficially ornamented with series of tubercles 
or fine ridges of ganoine. 
