1901.] NATURAL SCIENCES OF PniLADELPHFA. 621 



A. ray. The least depth of tlie caudal peduncle is equal to the 

 anterior interorbital region. 



The photophores are as follows: 3 mandibulars on each side of 

 the mandibles ; 2 operculars near the lower part of the margin of 

 the preoperculum ; 5 thoracic on each side; 4 ventrals on each 

 7«ide; 8 anals, a gap, then 9 more, in all 17 on each side; 3 pec- 

 torals on each side; 1 antero-lateral on each side a little posterior, 

 though above, the bases of the V., but nearer to the latter than to 

 the lateral line; 3 medio-laterals on each side, forming an oblique 

 ^ieries on each side, the lower a little anterior to the last ventral 

 photophores, and the uppermost immediately below the lateral line 

 and in advance of the first anal photophore; a single photophore, 

 the postero-lateral, almost on the lateral line and above and ante- 

 rior to the eighth anal photophore; 2 caudals upon each side inferi- 

 orly, and a single siipercaudal at the origin of the rudimentarv 

 caudal rays. The caudal, though somewhat damaged, was forked, 

 the lobes most likely rounded, and the lower a trifle the larger. The 

 lateral line consists of a single well -developed pore on each scale of 

 its course, which is supei'ior, and parallel with the dorsal profile of 

 the back. Scales 42 (?). Radii of D. 12. Radii of A. 22. 



My first impression was to regard this specimen as Myctophum 

 reiniger Goode and Beau, but a careful examination has revealed 

 the facts mentioned above ; and if, as Goode and Bean contended, 

 " the arrangement of the luminous spot is of the greatest value 

 in the classification of these fishes," there can be no reasonable 

 doubt that it is Liitken's Scopelus phengodes. 



Although the localities where Liitken obtained his examples were 

 all in southern latitudes, and very remote from that where the 

 present example was taken, I identify it with the above species 

 without any hesitation, as it agrees perfectly with the essential 

 characters given. Specimens from widely remote localities in the 

 case of deep-sea and oceanic fishes do not always necessarily form 

 u barrier to their identity as one and the same species. 



That M. phengodes and 31. reviiger are allied is also evident by 

 their long P., the large eye and .shape of the head, as seen on com- 

 parison with an example of the latter species. 



The example described above is in the collection of the Academy 

 of Natural Sciences of Philadelphia. It po ssesses a median 

 infero- caudal photophore. 



