﻿330 CKOSSOPTERYGII. 



trunk affords evidence of two " lateral lines " on each side, 

 the upper arising near the superior border of the oper- 

 culum, and the lower near the inferior extremity of the 

 clavicular plate. Purchased, 1851. 



24839. Three imperfect young individuals, laterally compressed, 

 associated upon one small slab ; Dura Den. The head 

 and clavicular plate are in each case preserved, but the 

 extremity of the tail is wanting and all the scales and 

 bones are much abraded. So far as preserved, the bones 

 of the head and opercular apparatus agree with those of 

 No. 2Ql\7b, and a marginal series of small conical teeth 

 is seen in the jaws. One pelvic fin is shown, apparently 

 displaying a trace of the lobation ; the first dorsal occurs 

 directly opposite to this ; and the large second dorsal 

 seems to arise somewhat behind the origin of the equally 

 large anal. Purchased, 1850. 



24839 a. Several fragments of small individuals ; Dura Den. 



Purchased, 1850. 



26122. Type specimen of Platygnathus jamesoni, Agassiz, being, as 

 pointed out by Traquair (loc. cit. 1888), the caudal ex- 

 tremity of a species of Holoptychius, and almost certainly 

 referable to H. flemingi ; Dura Den. By Agassiz the 

 second dorsal fin is described as the anal, while the true 

 anal and the inferior lobe of the caudal are regarded as 

 two dorsals or perhaps one large dorsal accidentally 

 divided. Purchased, 1851. 



(Other remains of this species are associated with Phanerojpleuron 

 andersoni, and catalogued on p. 247.) 



Scales of undetermined species of Holoptychius have been recorded 

 from the Old Red Sandstone of England 1 , and the following is a 

 similar specimen : — 



P. 5327. Imperfect impression of small scale, in conglomerate ; 

 Tortworth, Gloucestershire. 



Presented by the Earl of Ducie, 1887. 



i E. I. Murchison, Silur. Syst. (1839), pp. 175, 601 (from Crickhowell) ; 

 W. H. Baily, Eep. Brit. Assoc. 1864 (1865), Trans. Sect., p. 49, and Geol. Mag. 

 vol. i. (1864), p. 293. The so-called scales of Holoptychius from Devonshire 

 described by J. Phillips (Palseoz. Foss. Cornwall, Devon, &c, 1841, p. 133, 

 pi. lvii. figs. 256, 257) do not pertain to this genus. 



