﻿216 ANTIAECHA. 



distinguishable, and the tail is well shown. The caudal 

 scales are externally tuberculated and deeply overlapping ; 

 and the dorsal ridge-scales (/.) beyond the fin are very 

 distinct. The impression of one large fulcral scale is 

 seen upon the anterior margin of the dorsal fin (cL). 



Purchased, 1883. 



Pterichthys testudinarius, Agassiz. 

 [Plate Y. fig. 8; Plate VI. fig. 1.] 



1844. Pterichthys cornutus and P. testudinarius, L. Agassiz, Poiss. Foss. 



vol. ii. pt. i. p. 302 (names only). 

 1844. Pterichthys testudinarius, L. Agassiz, Poiss. Foss. V. G. R. p. 14, 



pi. iv. figs. 1-3. 

 1844. Pterichthys cornutus, L. Agassiz, ibid. p. 17, pi. ii. figs. l-o. 



[British Museum.] 

 1848. Pterichthys testudinarius, Sir P. Egerton, Quart. Journ. Geol. 



Soc. vol. iv. p. 312. 

 1848. Pterichthys cornutus, Sir P. Egerton, ibid. p. 313. 

 1855. Pterichthys testudinarius, F. M'Coy, Brit. Palseoz. Foss. p. 600. 

 1888. Pterichthys cornutus, ~R. H. Traquair, Geol. Mag. [3] vol. v. 



p. 509, and Ann. Mag. Nat. Hist. [6] vol. ii. pi. xvii. figs. 1-3. 



Type. Head and trunk ; Edinburgh Museum. 



Inferior surface of carapace narrowly ovate ; tail about equal in 

 length to the trunk. Pectoral appendages less than two-thirds as 

 long as the trunk, not expanded, tapering. 



Form. <Sf Log. Lower Old Red Sandstone : Lethen Bar, Nairn- 

 shire. ' 



P. 3202. One of the type specimens of P. cornutus, figured by 

 Agassiz, op. cit. pi. iv. fig. 2. Enniskillen Coll. 



P. 548, P. 3203. One of the type specimens of P. cornutus, in 

 counterpart, figured ibid. fig. 4. 



Egerton <$f Enniskillen Colls. 



P. 549, P. 3201. One of the type specimens of P. cornutus, in 

 counterpart, figured ibid. fig. 5. 



Egerton Sf Enniskillen Colls. 



28857 a. Ventral plates of trunk, visceral aspect, with right pec- 

 toral appendage and remains of tail. Purchased, 1854. 



49190. Trunk, ventral aspect, wanting the tail, with displaced head 

 and scattered plates of the carapace. The greater portion 

 of the specimen is shown, of the natural size, in PI. V. 

 fig. 8, and the various plates are indicated by the letter- 

 ing. Purchased, 1878. 



