﻿130 1CHTHYODOKTTLITES. 



Genus PHYSONEMUS, M'Coy. 



[Ann. Mag. Nat. Hist. [2] vol. ii. 1848, p. 117.] 



Syn. Xystracanthus, J. Leidy, Proc. Acad. Nat, Sci. Philad. 1859, p. 3. 

 Drepanacanthus, Newberry & Worthen, Pal. Illinois, vol. ii. 

 1866, p. 120. 



Spines much laterally compressed, strongly arched, often hook- 

 shaped ; base of insertion broad. Sides of exserted portion more or 

 less ornamented with tuberculated longitudinal ridges ; small den- 

 ticles present upon the concave edge. 



According to Newberry and Worthen, the form of the inserted 

 portion in the so-called Drepanacanthus proves that the spine was 

 arched forwards. 



Physonemus arcuatus, M'Coy. 



1848. Physonemus arcuatus, F. M'Coy, Ann. Mag. Nat. Hist. [2] 



vol. ii. p. 117. 

 1855. Physonemus arcuatus, F. M'Coy, Brit. Palaeoz. Foss. p. 638, 



pi. iii. i. fig. 29. 

 1883. Physonemus arcuatus, J. W. Davis, Trans. Roy. Dublin Soc. [2] 



vol. i. p. 367, pi. xlvii. fig. 8. 



Type. Woodwardian Museum, Cambridge. 

 The type species. 



Form. Sf Loc. Lower Carboniferous Limestone : Armagh and 

 Gloucestershire. 



P. 2239. Base of spine ; Armagh. Egerton Coll. 



P. 2519. Distal portion of spine ; Armagh. This is probably the 

 specimen assigned provisionally to Chalazacanthus verru- 

 cosus by J. W. Davis, loc. cit. p. 371. Enniskillen Coll. 



P. 2520-21. Two more imperfect specimens, both "decorticated"; 

 Armagh. Enniskillen Coll. 



38022. Similar specimen ; Black Rock, Bristol. Purchased, 1863. 



Physonemus attennatus, Davis. 



1883. Physonemus attenuatus, J. W. Davis, Trans. Roy. Dublin Soc. 

 [2] vol. i. p. 369, pi. xlvii. fig. 10. 



Type. Formerly in the Enniskillen Collection 1 . 



Form. 6c Loc. Lower Carboniferous Limestone : Armagh. 



1 See Introduction. 



