﻿ACANTHODID^. 13 



49668-9. One very stout specimen and an imperfectly preserved 

 caudal region, with impression of the head and abdominal 

 region; Thurso. Purchased, 1879. 



43967. Crushed fish, showing all the fin-spines ; Thurso. 



Purchased, 1872. 



38583. Slab with remains of several individuals. Purchased, 1864. 



Acanthodes mitchelli, Egerton. 

 [Plate I. fig. 7.] 



1860. Acanthodes antiquus, Sir P. Egerton, Rep. Brit. Assoc. 1859, 

 Trans. Sect. p. 116 (name only). 



1861. Acanthodes mitchelli, Sir P. Egerton, Rep. Brit. Assoc. 1860, 

 Trans. Sect. p. 77 ; and Figs. & Descrips. Brit. Organic Remains 

 (Mem. Geol. Surv.), dec. x. p. 61, pi. vii. 



1864. Acanthodes mitchelli, J. Powrie, Quart. Journ. Geol. Soc. vol. xx. 



p. 419. 

 1870. Acanthodes mitchelli, J. Powrie, Trans. Edinb. Geol. Soc. vol. i. 



p. 288, pi. x. fig. 1. 

 1888. Mesacanthus mitchelli, R. H. Traquair, Geol. Mag. [3] vol. v. 



p. 512. 



Type. Complete fish ; British Museum. 



A very small species, attaining a maximum length of 0*065. 

 Body elongated and slender, the greatest depth being contained 

 about six times in the total length ; cranial roof very coarsely 

 rugose or consisting of large, irregular, tesserae-like membrane bones. 

 Pelvic fins large, situated somewhat nearer to the anal than to the 

 pectorals ; a pair of minute spines in advance of the pelvic pair. 

 Pelvic spines about half as large as the pectorals, and two thirds as 

 long as the anal. Dorsal fin arising behind the anal, larger than 

 the latter. 



Form. Sf Loc. Lower Old Red Sandstone : Forfarshire. 



P. 560, P. 1330. Type specimen and a smaller more imperfect fish ; 

 Farnell, Forfarshire. The minute intermediate ventral 

 spines are shown in Egerton's outline sketch, but not in 

 the detailed enlarged figure, and apparently not in the 

 original specimen. The second fossil exhibits these 

 spines. Egerton Coll. 



35909. Two contorted fishes ; Farnell. 



Presented by James Powrie, Esq., 1861. 



38594. Almost complete fish, lateral aspect, shown, of the natural 

 size, in PI. I. fig. 7. 



Presented by James Powrie, Esq., 1864. 



