FISHES OF HAWAIIAN ISLANDS. 
597 
scale of the series; each of these scales is greatly shortened in its lower half to make room for the 
special scale of the photophore, and is but little more than half the height of the other scales; the 
posterolateral is over, or very slightly in advance of the last antero-anal, the latter vertically over 
the fourth anal ray before the last and below the front of the adipose fin. 
The photophores are invariable in number and position, except those of the anal series. Our 
material includes 63 specimens. As each side must be tabulated separately, we have for consideration 
126 cases: 
The antero-anals are 8 in number in 7 cases, 9 in number in 88 cases, 10 in number in 31 cases. 
The postero-anals are 5 in number in 62 cases, 6 in number in 55 cases, 7 in number in 9 cases. Com- 
bining these gives a total range of 13 to 17, distributed as follows: 13 in 3 cases, of which 2 occur bilat- 
erally, 1 unilaterally; 14 in 37 cases, of which 24 occur bilaterally, 13 unilaterally; 15 in 74 cases, of 
which 60 occur bilaterally, 14 unilaterally; 16 in 10 cases, of which 6 occur bilaterally, 4 unilaterally; 
17 in 2 cases, of which none occur bilaterally, 2 unilaterally. 
The usual combinations are 94-5 (32 cases) 9+6 (48 cases) and 10+5 (23 cases), one or another of 
these combinations occurring on one or both sides of 56 out of the 63 specimens at hand. The 2 sides 
do not vary independently in this species. Perfect bilateral symmetry occurs in 46 specimens, and in 
6 others the lack of symmetry is plainly due to the dropping out of the second or the penultimate 
member of the anterior group. In no case does the difference in number of anals on the 2 sides 
exceed 1. 
General color dusky brown on upper half of head and body; sides of head and lower half of sides 
silvery, the latter everywhere coarsely specked with brown; anterior dorsal dusky, base of caudal 
blackish, other fins translucent. In the type, 7 scales on the back of the caudal peduncle are under- 
laid by pearly (luminous) spots, agreeing in this respect with M. opcilinum. None of the smaller speci- 
mens (47 inm. and less) shows any trace of this luminous area. 
M. mcirgaritatum agrees in outline very closely with Liitken’s figure of M. affine (Spolia Atlantica, 
II, Scopelini, 1892, p. 252). It seems to differ in the more numerous scales of the lateral line, in the 
more anteriorly placed break in the anal series, the more elevated posterolateral, and in the somewhat 
different range of variation in the number of anal spots. In M. affine, the antero-anals vary from 7 to 
10 (frequently 8 or 9); in M. margaritatum, the number 7 does not occur, and 8 very rarely, 9 and 10 
prevailing. In M. affine, the postero-anals vary from 4 to 6 (frequently 5 or 6); in M. margaritatum, 
no specimens have 4, but a few have 7. 
The species was taken at the following stations: Nos. 3878, south of Lanai; 3926, west of Oahu; 
3927, west of Niihau; 3929, southwest of French Frigate Shoals; 3930, near Laysan Island; 3931, near- 
Lay san Island; 3932, near Laysan Island; 3980, south of Oahu; 4010, west of Oahu; 4011, west of Oahu; 
4145, west of Niihau, and 4188, between Honolulu and San Francisco, lat. N. 28° 13 / 42+ long. W. 
145° W 00+ all at the surface. 
Myctophum evermanni, new species. Plate 70, Fig. 2. 
Type, 29 mm. long, from station 3980, south of Oahu, taken at the surface; type, No. 51521, U. S. 
Nat. Mus. 
Belated to M. boops and M. humboldti, but with a short postero-anal series of photophores (4 to 6), 
the first of the series much farther back than in related species, a little behind the last anal ray. In 
M. boops, Eichardson, and M. humboldti (Risso), the break in the anal series is but little behind the 
middle of the fin. 
Total length, excluding caudal, 22 mm. ; greatest depth of body 22 hundredths of this length; least 
depth of caudal peduncle 7; length of head 33; diameter of orbit 8; frontal width over middle of eye 9; 
length of snout 7; length of maxillary 23; distance from tip of snout to front of dorsal 51; from front 
of dorsal to adipose dorsal 36; from tip of snout to front of anal 50; base of anal 26; ventrals 16; 
pectoral broken. D. 15, the 4 anterior rays much shortened; A. 20; lateral line with 39 tubes; 
9 longitudinal series of scales where body is widest, not including the median series above and below. 
Head and body very slender, the caudal peduncle deeper in proportion; head tapering forward, 
the snout not bluntly rounded; maxillary very long, little widened posteriorly, half its length behind 
middle of eye; eye little longer than snout; preopercular margin not very oblique. 
Origin of the dorsal slightly behind insertion of ventrals, its posterior rays slightly overlapping 
the anal; vertical from front of adipose dorsal passing through the posterolateral photophore and the 
