﻿514 ACTINOrTERTGII. 



Genus ATHERSTONIA, A. S. Woodward. 



[Ann. Mag. Nat. Hist. [6] vol. iv. 1889, p. 241.] 



8 yii. Hypterus, R. Owen, Catal. Foss. Kept. S. Africa, 1876, p. ix. (name 

 only). 



Trunk fusiform, elongated but robust. Mandibular suspensorium 

 very oblique and gape wide ; [teeth unknown] ; head and opercular 

 bones externally rugose and tuberculated. Fins powerful, with 

 broad, laterally compressed rays, frequently articulated and dis- 

 tally bifurcated ; anterior pectoral fin-rays unarticulated in their 

 proximal half ; pelvic fins with an elongated base-line, the dorsal 

 arising between the pel vies and the anal, and the last-named fin 

 remote, much extended. Scales large or of moderate size, exter- 

 nally marked with oblique striae, and subdivided into smaller scales 

 at the base of the dorsal, anal, and pelvic fins ; dorsal margin with 

 a continuous series of very large, deeply overlapping ridge -scales. 



Atherstonia scutata, A. S. Woodward. 



1876. Hypterus bainii, R. Owen, Catal. Foss. Rept. S. Africa, p. ix. 



(name only). 

 1889. Atherstonia scutata, A. S. Woodward, Ann. Mag. Nat. Hist. [6] 



vol. iv. p. 242, pi. xiv. figs. 1-3. 



Type. Nearly complete fish ; British Museum. 



The type species, attaining a length of about 0*35. Head with 

 opercular apparatus occupying about one-fifth of the total length. 

 Pelvic fins arising somewhat nearer to the pectorals than to the 

 anal ; the latter much larger than the dorsal, and for the greater 

 part behind this fin. Flank-scales slightly deeper than broad ; 

 none posteriorly denticulated. Scale-ornament consisting of sharp 

 striae, often bifurcating and intercalated, slightly oblique on fehe 

 principal scales of the flank. 



Form, fy hoc. Beaufort Beds (Lower Karoo Series) : Cape Colony, 

 South Africa. 



P. 4735. Type specimen ; Colesberg. 



Presented by the Hon. W. Gfuybon Ather stone, M.D., 1884. 



46007. Imperfect trunk, labelled Hypterus bainii in Owen's hand- 

 writing : Alice, near Fort Beaufort. 



Presented by the Trustees of the Albany Museum, 1873. 



36260. Portion of trunk with dorsal ridge-scales and fin; Brak River, 

 Fort Beaufort, Presented by A. G. Bain, Esq., 1862. 



