﻿ONYCH0D0NTID.E. 



391 



1890. Glyptokemus kinnairdi, R. H. Traquair, Proc. Roy. Soc. Edinb. 

 vol. xvii. p. 389. 



Type. Fishes ; Museum of Practical Geology. 



A very slender species, attaining a maximum length of about 0*4. 

 Head with opercular apparatus more than twice as long as its 

 maximum depth, comprised about five times in the total length. 

 Parietal region long and narrow, exceeding the frontal region in 

 length ; jaws much elongated ; principal jugular plates rapidly 

 tapering and acuminate in front, three and a half times as long 

 as their maximum breadth. Pelvic fins remote, arising midway 

 between the pectorals and the extremity of the caudal. Scales 

 relatively smaller than in G. minor, these and the head-bones orna- 

 mented with sharper, more irregularly developed reticulating rugae 

 than in the latter species. 



This is the type species of the so-called Glyptolcemus. 



Form, fy Loc. Upper Old Red Sandstone : Fifeshire. (?) Upper 

 Devonian : Belgium. 



26117 a. Head and imperfect trunk, ventral aspect, showing a 

 fragment of the left pectoral fin ; Dura Den. The speci- 

 men is associated with the anterior half of the head of 

 another individual, and remains of Holoptychius. 



Purchased, 1851. 



P. 6285. Fragment of trunk ; Dura Den. EnnisJcillen Coll. 



Family ONYCHODONTID^l. 



Scales cycloidal, deeply overlapping. Head and opercular appa- 

 ratus with well-developed membrane- bones. Dentary bone of 

 mandible thin and deep, bearing a single close series of large conical 

 teeth, flanked by an outer series of very minute teeth ; an azygous 

 scroll-like element occupying a groove in the dentaries at their 

 symphysis. Teeth plicated only at the base, with a central cavity ; 

 dentary teeth tipped only, presymphysial teeth completely enve- 

 loped with enamel. 



The single known genus of this family, Onychodus, has hitherto 

 been found only in a fragmentary condition. The form and pro- 

 portions of the trunk and fins thus await discovery. 



