412 
ACTINOPTEKYGIT. 
P. 1939, P.1942, P. 3936 b, P. 3938. Two fine specimens in 
counterpart, and a more imperfect fish, all labelled by 
Agassiz. Egerton <$f Enniskillen Colls . 
P. 9445. Fish 0‘09 in length, in counterpart. Purchased. 
P. 1939 a, P. 3936 a. Two small specimens from the Gazola 
Collection. Egerton Sf Enniskillen Colls. 
P. 5135. Two imperfect small specimens. 
Presented by Mrs. M. E. Fort, 18bh. 
The following specimens are too imporfoct for determination, but 
the first was referred to Myripristis by Agassiz : — 
P- 644-a. Two imperfect heads with opercular apparatus, the first 
intended to bo tho typo specimen of Myripristis toliapicas, 
Agassiz, recorded by namo only in ltep. Brit. Assoc. 1844 
(1845), p. 307 ; London Clay, Sheppey. The incomplete 
cranium in the second specimen seems to be quito different 
from that of Myripristis. Egerton Coll. 
Genus HOLOCENTRUM (Artedi), Cuvier. 
[Regne Animal, ed. 2, vol. ii. 1829, p. 150.] 
Trunk moro or less elongated and laterally compressed. Frontal 
region of skull gently rounded, not ridged; cleft of mouth small, 
mandible not prominent, and teeth minute. Opercular bones and 
suborbitals serrated; operculum with two spines; angle of p re " 
operculum produced into spine. Vertebra; 10 or 1 1 in the abdominal, 
15 or 16 in the caudal region. Pelvic fins with ono spine and 
7 divided rays, arising behind the origin of the pectorals. Dorsal 
fin much extended, divided into two portions, the foremost spinous , 
anal fin not much extended, with 4 spines, of which tho third is 
relatively stout and long ; caudal fin deeply cleft. Scales large and 
ctenoid, more or less uniform. 
A figure of the skeleton of an existing species of this genus is 
given by Agassiz, Poiss. Foss. vol. iv. pi. B. fig. 1. The existing 
species live at tho surface of tropical seas. 
Holocentrum macrocephalum , Blainville. 
1796. Holocentrus sogo , G. S. Volta, Ittiolit. Veron. p. ccx. pi. fi- fig' 
( errore ). 
1796. Ch&todon saxatilis, G. S. Volta, ibid. p. cclxv. pi. lxiv. fig- 1 
(errore). 
