604 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



MCZ 6600(8), 25882(1), 26389(4), 32293(1), 34990(3), 34993(6), 35151(3), 

 and Atlantis station 2959(1). 



USNM 10143(2), 40053(2), 100341(1), 100526(1), 100542(1), 102779(5), 

 102780(8), 102781(3), 102782(8), 102783(1), 102784(2), 102785(2), 102786(6), 

 163362(1), 164296(3). 



WHOI RHB454(13), RHB456(3), RHB483(2), RHB569(3), RHB572(7). 



Distinctive characters: A. hemigymnus and A. intermedins 

 form what may be called the hemigymnus complex. The former 

 appears to be confined to the Atlantic and Mediterranean Sea, and 

 A. intermedins to the Pacific and Indian Oceans. My opinion is 

 based on the specimens available. In each of these vast regions 

 there may be populations or even subspecies that could be distin- 

 guished, but this possibility requires verification through special 

 studies of hundreds of specimens from each of numerous localities. 



The following characters are possessed by both species: Lower 

 preopercular spine almost straight and directed nearly straight 

 downward; upper preopercular spine rather long, curved a little 

 upward and outward, notably extending past rear margin of bony 

 edge of preopercle; a single serrated postabdominal spine directed 

 posteriorly, the lower margin of spine almost in line with lower edge 

 of abdomen, usually a minute spinule dorsally on posterior basal 

 part of postabdominal spine. 



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

 2, p. 592, measurements made are given in table 3, p. 593. This species 

 is notable for its slender body behind the preanal group of photo- 

 phores, the compact nature of the anal and subcaudal groups of 

 photophores, and the wide spaces separating preanal, anal, and es- 

 pecially the subcaudal group of photophores from the anal group. 

 A white bar occurs between preanal and anal and another between 

 anal and subcaudal groups of photophores. These white bars are 

 separated by a dark bar. 



Range: This species appears to be replaced in the Pacific and 

 Indian Oceans by A. intermedins. A. hemigymnus is the only species 

 of this genus that has so far been reported from the Mediterranean Sea. 

 Numerous specimens were available for study in over 85 lots from the 

 following general localities : Mediterranean Sea (54) ; Azores (9) ; off 

 Iceland (4); vicinity of Bermuda (60); off New York (18); off South 

 Carolina (1); off Georgia (1); Bahamas and West Indies (110); Carib- 

 bean Sea (1). I have not seen any specimen of A. hemigymnus from 

 the Gulf of Mexico. The farthest north from which I have seen a 

 specimen was lat. 42°56' N., long. 30°19' W. (MCZ 34990) and to 

 a depth of 3,000 meters (Pappeuheim, 1914). It also occurs in the 

 South Atlantic. 



