OSTEOLT-'PIDiE. 
375 
The attenuated caudal lobe is distinctly exhibited, and is 
fringed above by a series of short fin-rays. 
Purchased , 1879. 
33140. Trunk with pelvic, dorsal, and anal fins, and the base of 
the caudal; Thurso. The specimen is shown, of the 
natural size, in PI. XIII. fig. 3, and the fins indicated by 
the lettering. Adjoining each dorsal fin is a very large, 
antero-posteriorly elongated ridge-scale. 
Purchased , 1857. 
42440. Imperfect head and trunk, wanting the extremity of the 
tail and the anal fin ; South Head, Wick. Large conical 
teeth, simple in section, are shown in the jaws ; and the 
lobation of the paired fins is distinct. Peach Coll , 
Genus DIPLOPTERUS, Agassizi. i ' ^ 
[Poiss. Foss. vol. ii. pt. i. 1835, p. 113.] 
Cranial roof-bones in advance of the parietals fused into a con¬ 
tinuous shield, with a median frontal foramen ; an anterior azygous 
jugular plate present. Teeth rounded in transverse section. Dorsal 
fins opposed to the pelvic pair and the anal respectively. Tail 
almost diphycercal; caudal fin unsymmetrically rhomboidal, the 
upper lobe somewhat smaller than the lower. Scales smooth and 
punctate. 
Diplopterus agassi&i, Traill. 
1841. Diplopterus agassis, T. S. Traill, Trans. Hoy. Soc. Edinb. vol. xv. 
p. 89. 
1844. Diplopterus macrocephalus , L. Agassiz, Poiss. Foss. V. G. R. 
p. 54, pis. xvi., xvii. [British Museum and Forres Museum.] /nttAeCI- ■ 
1844. Diplopterus affinis , L. Agassiz, ibid. pp. 55, 138, pi. xxxi.a. 0 ^^^ . 
fig. 27. .2 
1844. Diplopterus borealis, L. Agassiz, ibid. p. 55, pi. xviii. fig.l (pfio-,2). 
T. S. Traill Collection.] cL&. 
1848. Diplopterus gracilis, F. M‘Coy, Ann. Mag. Nat. Hist. [2] vol. ii. 
p. 305. [TV oodwardian Museum, Cambridge,! 
1 This generic name is preoccupied (Latreille, 1847, and Boie, 1826), and 
M‘Coy accordingly proposed the slightly modified, though essentially identical, 
form Diplopter ax. As, however, the fish in question has been universally 
quoted tor fifty years under the name of Diplopterus. we are unwilling to 
suggest a change which would necessitate future ichthyologists adopting a dual 
nomenclature. 
