1. ARGTBOl'ELECUS. 385 



regular scales ; . series of luminous (phosphorescent) spots run along 

 the lower side of the head, body, and tail. Head large, compressed, 

 and elevated, with the bones thin, but ossified. Cleft of the mouth 

 wide, vertical, with the lower jaw prominent. The margin of the 

 upper jaw is formed by the intermaxillary and maxillary*, both 

 these bones having a sharp edge, which is beset with a single series 

 of minute teeth ; lower jaw and palatine bones with a series of small 

 curved teeth. Eyes rather large, and, although lateral, directed up- 

 wards and very close together. Pectorals well developed ; ventrals 

 very small. The humeral arch and the pubic bones are prolonged 

 into flat pointed processes, which project in the median line of 

 the belly; a series of imbricate scutes runs from the humeral to 

 the pubic spine, forming a sort of serrature along the belly. The 

 dorsal fin is short, and occupies about the middle of the length of 

 the fish ; it is preceded by the first commencement of the formation 

 of a spinous dorsal, several neural spines being prolonged beyond the 

 muscles, forming a triangular osseous plate. Adipose fin rudimen- 

 tary ; anal fin short ; caudal forked. Gill-opening very wide, the 

 outer branchial arch extending forward to behind the symphysis of 

 the lower jaw, and beset with veiw long gill-rakers; branchiostegals 

 nine ; pseudobranchiae present ; air-bladder present. Pyloric ap- 

 pendages four. 



Mediterranean and Atlantic. 



1. Argyropelecus hemigymnus. 



Argyropelecus hemigymnus, Cocco, in Giorn. Sc. Sic. 1829, fasc. 77. 



p. 146 ; Bonap. Faun. Pal. Pesc. text ; Cuv. fy Val. xxii. p. 398. 

 Sternoptyx mediterranea, Cncco, in Giorn. il Faro, 1838, iv. p. 7. fig. 2 ; 



Bonap. Faun. Ital. Pesc. fig. 

 hemigymnus, Valenc. in Cuv. Regne Anim. 111. Poiss. pi. 103. fig. 3. 



B. 9. D. 7-8. A. 11. P. 9. V. 5. 



The height of the body equals the distance between the gill- 

 opening and the root of the caudal ; tail slender ; posterior corner 

 of the mandible and angle of the praeoperculum, each with a small 

 triangular spine; tail without spines. The pectoral fin extends 

 nearly to the origin of the anal. 



Mediterranean and Atlantic. 

 a-b, c-f. Two inches long. Messina. 

 g, h-i. One inch and a half long. Mediterranean. 

 k. Many specimens. 



* Valenciennes's descriptions are rather confused as regards the relal ive length 

 of the intermaxillary of these fishes : at p. 394 he compares the upper jaw of 

 the Mediterranean species (A. hemigymnus) with that of Gonosfoma on account 

 of the long intermaxillaries, whilst in reality Gonosfoma is distinguished by the 

 shortness of these bones ; and in the description of A. hemigymnus he calls the 

 intermaxillaries short. In all these fishes the intermaxillaries taper into a fine 

 fibrous point, and it is impossible to fix upon the exact spot where the bone ceases ; 

 the essential point is, that the maxillary is tothed in such a manner that its den- 

 tition is merely the continuation of that of the intermaxillary ; whether the inter- 

 maxillary extends a little more or less downwards towards the commissure, is of 

 very subordinate importance. 



vol. v. 2 c 



