120 
ICHTHYODOKULITES. 
P. 8254. Two specimens ; Allemagne. Enniskillen Coll. 
A fragment of an Asterolepid appendage from the Devonian of 
Russia has been erroneously assigned to this genus under the name 
of Pristacanthus mcirinus , E. von Eichwald (Bull. hoc. Imp. Hat. 
Moscou, vol. xvii. 1844, p. 826 ( marianus ), and ibid. vol. xix. 1846, 
pt. ii. p. 294, pi. x. figs. 10, 11, and Leth. Rossica, vol. i. 1860, 
p. 1605). 
Genus C^LORHITNCHUS, Agassiz. 
[Poiss. Eoss. vol. v. pt. i. 1844, p. 92.] 
Syu. Cylindr acanthus, J. Leidy, Proc. Acad. Nat. Sci. Philad. 1856, 
p. 12. 
Spine very long, slender, and gradually tapering, rounded in sec¬ 
tion, and without denticles ; external surface longitudinally ridged 
and grooved, each ridge corresponding to a wedge-shaped plate, 
which forms a small sector of the spine. Central cavity relatively 
small, sometimes in part simple, but usually divided by a median 
partition; a division plane passing through the middle of the 
partition, thus allowing the spine to be readily split into two sym¬ 
metrical halves. 
This ichthyodorulite was originally mistaken by Agassiz for the 
rostrum of a Xiphioid Teleostean, and its truly dermal nature was 
first demonstrated by W. C. Williamson \ A Cretaceous example 
in the Willett Collection, Brighton Museum, suggests that the fossil 
may he referable to an undetermined Chimseroid 1 2 . 
1784. u Petrification inconnue,” Burtin, Oryctogr. Bruxelles, pi. vi. 
figs. A-E. 
1844. Ccelorhynchus rectus, L. Agassiz, Poiss. Foss. vol. v. pt. i. p. 92 
(name only). 
1850. Ccelorhynchus/, F. Dixon, Foss. Sussex, p. 112, pi. x. figs. 14-17, 
pi. xi. fig. 26. J 
1861. Ccelorhynchus rectus, R. Owen, Palaeontology, ed. 2, p. 172, 
woodc. fig. 80. 
1871. Ccelorhynchus burtini and C. rectus, H. Le Hon, Prelim. Mem. 
Poiss. Tert. Belg. p, 14. 
1871. Ccelorhynchus burtinii and C.. rectus, P. J. Van Beneden, Bull. 
Acad. Roy. Belg. [2] vol. xxxi. p. 500. 
Coelorhyiaciras rectn§ ? Agassiz. 
1 Phil. Trans. 1849, p. 471, pi. xliii. figs. 35-37, and ibid. 1851, p. 667. 
2 A. S. Woodward, Ann. Mag. Nat. Hist. [6] vol. ii. (1888), p. 223. 
