e 



s 



Q 1 



135 



II. Body very low and elongate. No pseudobraiichire : — 



1. Doisal fin in the after lialf of the body, arising opposite the 

 origin of the anal : anal long ... ... ... Cyclothone. 



2. Dorsal fin in the middle of the body, well in advance of the anal : 

 anal moderately long ... ... ... ... PnoTrcHTHTS. 



3. Dorsal fin placed far forward, hardly a bead-length behind the 

 occiput: anal short : no gill-rakers ... ... ... Chaoliodus 



Argyropelecus, Cocco. 



Argyropeleciis, Cocco, Giorn. Sci. Sicil. 1829: Cavier and Valenciennes. Hist. Nat. Poiss. XXII. p. 332- 

 Giiuther, Cat. Fislies, V. p. 389 : Goode and Bean, Oceanic Ichthyology, p. 125 : Jordan and Erermann Fishes N 

 Amer., p. 603. 



Pleurothyris, Lowe, Fishes of JLadeira, p. 64. 



Head and body elevated and compressed : tail narrow, abruptly delimited 

 from the trunk, like the handle of a hatchet. Body covered with a thin silvery 

 skin, which is superficially wrinkled, as if thin scales had been loosely attached 

 to it. Series of " bull's-eye "-like luminous organs along the ventral border of 

 head, body, and tail. A series of imbricate scutes forms a serrature along the 

 middle line of the belly, from the throat to the ventral fins. 



Cleft of the mouth wide, vertical, with the lower jaw prominent, and the 

 margin of the upper jaw formed by the premaxilla and maxilla : minute teeth in 

 a single row in the jaws and palatines. The jaw-bones, like all the bones of 

 the head, are very thin, but well-ossified. 



Eyes rather large, lateral but directed upwards and very close together. 



Gill-opening very wide, very long gill-rakers on the outer side of the first 

 branchial arch. Nine branchiostegals. Pseudobranchi^ present. 



Dorsal fin short, situated about the middle of the back, preceded by a thin 

 transparent triangular osseous plate in which the ends of several neural spines 

 are visible. Anal short. Caudal forked. Adipose dorsal rudimentary. 



Pectorals well developed, situated near the ventral profile : ventrals small : 

 both the humeral arch and the pubic bones project strongly, as flat spines, in the 

 niiddle line of the belly. 



An air-bladder. Four pyloric appendages. 



Distribution : Atlantic, Mediterranean, Bay of Bengal. 



111. Argyropelecus heinigijimiiis, Cocco. 



ATyyropelecus hemigymnxts, Cocco, Giorn. Sci. Sicil. 1829 : Bonaparte, Fann. Ital. Pesc, text : Cnv. & Val., Hist. 

 Nat. Poiss. XXII., p. 398 : Giinther, Cat. Fishes, V., p. 385, and Challenger Ueep-Sea Fishes, p. 167 : Vaillant, Exp. 

 Soi. Travaillenr et Talisman, Poiss., p. 103 : Goode and Bean, Oceanic Ichthyology, p. 126, fig. 147 : Jordan and 

 Everniann, Fishes N. Amer. p. 604. 



Sternoptyx mcditerranea, Cocco, Giorn. II Faro, 1838, IV., p. 7, fig. 2: Bonaparte, Faun. Ital. Pesc, fig. 



Stemoptyx hemigymnus, Cuvier, U^gne Animal, Poiss., pi. 103, fig. 3. 



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



Greatest height of the body about 2- times the greatest height of the tail, 

 and about half the total length without the caudal fin. Major (vertical) diameter 



