596 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



3a. Lower edge of pectoral shield smooth or with only a few weak spines or 

 scallops; greatest depth of pigmented body contained 2.1 to 2.4 times 

 in standard length. (Atlantic Ocean and ? Indian Ocean.) 



affinis Garman 



3b. Lower edge of pectoral shield with spines or sharply pointed scallops; 



greatest depth of body contained 1.9 to 2.1 times in standard length. 



(East Pacific and Hawaiian Islands.) .... pacificus, new species 



2b. One or two postorbital spines (usually two on adults) ; dorsal blade high, 



length of exposed part of last spine contained 1.5 to 1.9 times in base of 



soft dorsal; palatines toothless or with only a few feeble teeth; origin of 



base of soft dorsal notably above level of pigmented base of dorsal 



blade; greatest depth of pigmented part of body 1.9 to 2.0 times in 



standard length. Ventral edge of pectoral shield with sharp-pointed 



scallops. (Atlantic.) gigas Norman 



lb. Supra-abdominal, preanal, anal, and subcaudal groups of photophores 

 not in a straight or continuous line. 

 4a. A single postabdominal spine. 



5a. Postabdominal spine with both edges serrated, directed backward and 

 a little ventrally with a minute spinule on dorsoposterior base; lower 

 preopercular spine nearly straight, directed almost straight downward; 

 upper preopercular spine, rather long, curved a little dorsally, notably 

 extending past rear bony edge of preopercle; preanal, anal, and sub- 

 caudal groups of photophores notably separated by wide spaces, the 

 distance between the anal and subcaudal groups greater than the over- 

 all width of the group of anal photophores. 

 6a. Tip of longest spine in dorsal blade with one to three hooks or points; 

 ventral edge of bony pectoral shield smooth. (Atlantic and 



Mediterranean.) hemigymnus Cocco 



6b. Tip of longest spine in dorsal blade smooth, without hooks; ventral 

 edge of bony pectoral shield with a few minute points, these are 

 strongest in small specimens (15 mm. and shorter in standard 

 length). (Central and Western Pacific and Indian Oceans.) 



intermedins Clarke 

 5b. Postabdominal spine smooth edged, directed ventrally, and curved some- 

 what anteriorly; preopercle at lower angle with a spine pointing straight 

 downward and curved a little outward, the upper preopercular spine 

 small, pointing outward, its tip not extending past rear margin of 

 bony edge of preopercle. (Atlantic Ocean and Lord Howe Island in 



the Pacific Ocean) amabilis (Ogilby) 



4b. A pair of smooth postabdominal spines. 



7a. Upper preopercular spine short, directed a little outward, not reaching or 

 scarcely reaching past bony posterior edge of preopercle; lower pre- 

 opercular spine directed downward and slightly curved forward and 

 outward. 

 8a. Posterior postabdominal spine longer and heavier than anterior one, 

 directed posteroventrally and sometimes with 1 or more spinlets 

 on the ventral edge; angle between postabdominal spines 70 to 

 100 degrees; anterior postabdominal spine directed ventrally and 

 curving forward, its length as long as or longer than lower pre- 

 opercular spine; greatest depth of pigmented part of body 1.0 to 

 1.1, and length of dorsal blade 4.5 to 6.5 times, both in post- 

 orbital length of body. (Atlantic, Western and Eastern Pacific, 

 and Indian Oceans.) . . . aculeatus Cuvier and Valenciennes 



