MARINE SILVER HATCHETFISHES — SCHULTZ 609 



directed a little outward and posteriorly but not extending beyond 

 bony edge of preopercle; 2 post abdominal spines, the anterior one 

 directed ventrally and curving a little forward, the rear spine much 

 longer and stronger, directed posteriorly and curving ventrally; pos- 

 terior spine sometimes with 1 or 2 spinelets on the ventral side; the 

 angle between postabdominal spines about 70° to 100°; space between 

 anal group and subcaudal group of photophores rather narrow, about 

 equal to width of last 3 anal photophores; supra -abdominal, preanal, 

 and anal photophores not in a straight line; caudal peduncle crossed 

 with a white or pale bar between anal and subcaudal groups of photo- 

 phores; translucent part of abdominal keel notably wider than width 

 of middle two anal photophores. 



Description: Counts made are given in table 1, p. 591, and table 

 2, p. 592; measurements made are given in table 3, p. 593. 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 postorbital length of bod}^. When it reaches 

 a standard length greater than 25 mm., this deep bodied species 

 develops a series of spines under the subcaudal photophores, a double 

 series in front of subcaudal photophores, and a double group around 

 the anus and 3 flat bonylike spines between the 2 parts of the anal 

 fin; the bony ridges on head and dorsal blade also develop series of 

 bony serrae; these occur on both males and females. 



The four subcaudal photophores of equal size are in a straight 

 line, whereas the first and last two anal photophores are notably 

 larger than the middle three and dorsal edges are not in a straight 

 line. 



In alcohol there is a white bar across caudal peduncle between 

 anal and subcaudal group of photophores up to a length of about 

 50 mm., after which it darkens like rest of body; base of lower lobe 

 of caudal fin with a blackish posterior extension at least one-fourth 

 the length of lower caudal fin rays. 



Some specimens are difficult to distinguish from olfersi if the post- 

 abdominal spines are damaged. However, aculeatus has a deeper 

 body; the depth is less than 1.1 in postorbital length, whereas in 

 olfersi it is 1.2 or greater. 



Range: This species occurs in abundance in the Atlantic and 

 Pacific Oceans and is also found in the Indian Ocean. Specimens 

 were examined from the following localities: Pacific localities: Japan 

 (1), Philippines (1), Galapagos (15), in Pacific off Colombia (1). 

 Atlantic localities: Grand Banks (5), off New York (51), off Deleware 

 (10), middle North Atlantic (2), off North Carolina (2), off South 

 Carolina (1), vicinity of Florida (9), Gulf of Mexico (3), Bahamas 

 (1), Cuba and West Indies (9), Burmuda (43), Caribbean (16), off 

 Azores (2). 



