DISCUSSION OF SPFX'IES AND THEIR DISTRIBUTION. 73 



dorsal base is two-thirds that of head. Origin of ventral under tenth scale of lateral line; 

 it (Iocs not reach to vent. Pectoral short, its Length nearly t vro-thirds that of head. Adipose 

 dorsal preseul : its origin over thirtieth scale of lateral line. Anal origin under eighteenth 

 scale of lateral line; the end of its base under thirtieth scale. Length of anal base equals 

 thai of head. Caudal is rather small and moderately lurked. 



Mediolateral photophores three, in straight, obliquely ascending line; anterolateral one; 

 posterolateral one, under soft dorsal and over and slightly in advance of break in row of 

 superanals, which is above root of last ray of anal. Number of superanals s+6. 



In most of tin' specimens of .1/. opalinum examined , the 6 or 8 scales on the top of the 

 caudal peduncle, immediately in front of the caudal tin. are luminous. 



MYCTOPHUM PHENGODES, (LttTKKN), Goodi and Bean. 



Scopelus phengodea, LOtken, Spolia Atlanta ea, n, 1892, 253, Fig. 11. 



A species resembling in general appearance our Myctophum punctatum, from which it 

 is distinguished by having a long, falcate pectoral, the tip of which extends almost to the 

 vertical from the vent, and is uearer to the row of mediolateral photophores than to the 

 anterolateral. This form has. asin .1/. punctatum, the posterolateral considerably in advance 

 of the soft dorsal, and has the precaudal photophores much farther apart (a character upon 

 which some stress is laid by Liitkeu, but which seems to us of le ss importance than the 

 position of the posterolateral photophore). Number of superanals, G-7 + 7-9. 



Radial formula: D. 12; A. 21; L. hit. 38. 



Liitkeu had it from the Atlantic, south of the equator, presumably from surface. 



MYCTOPHUM HUMBOLDTII (Risso). (Figure82.) 



Gasteropelecus Sumboldti, Risso, Icth. Nice, 358, pi. 10, lit;. 38. 



Scopelus Sumboldti, l,'i ;so, Mem. Aocad. So. Torino, wv, 1820, 206. pi. 10, fig. 2. — Gunther, Cat. Fish. Brit. 

 Miis., V. |n7. — Giglioi.i. Elenco, 100. 



Height of body is one-fifth of total length (without caudal), length of head two-sevenths. 

 Least depth of tail two fifths of height of body; depth of head 1?- in its length. Diameter 

 of eye a little less than one third of length of head; distance between posterior margin of 

 orbit and preopercular edge one-half diameter of eye. Snout short, obtuse, its upper pro- 

 tile descending in strong curve. Maxillary reaches nearly to angle of preopercnlum, and 

 slightly dilated behind. Origin of dorsal somewhat nearer to end of snout than to root of 

 caudal, above root of inner ventral rays; its hist ray before vertical from origin of anal. 

 Pectoral extends to posterior third of ventral. Scales smooth, stiff. Mediolateral photo- 

 phores, 2; anterolaterals, 2; posterolateral, 1, (over break in anal series) which, as in .1/. 

 punctatum, is considerably in advance of the vertical connecting the root of the soft dorsal 

 with those of the last rays of the anal. Caudal photophores somewhat apart as in .1/. phen- 

 godes. Superanals 7-9+4-9. Radial formula: I). 12-14; A. 20-22; L. lat, 40-42. 



This species was first described from the Mediterranean about Nice, but appears to be 

 rare. The British Museum had specimens from the eastern Atlantic. The Albatross 

 obtained a specimen (No. 43772, U. S. N. M.) upon the surface, at 7 p. m., from station 2727, 

 in 36° 35' N. lat., 74° 03' 30" W. Ion., and also a very line specimen (No. 43773, U. S. N. M.) 

 from station 2724, in 36° 47' N. lat., 73' 25' W. Ion., at a depth of 1,041 fathoms. 



Liitkeu had a number of specimens of M. Humboldtii {op. <it.. p. 254, tic;. 2) from the 

 following localities: X. lat. 34° 20', W. Ion., 18° 30'; N. lat, 12° 12', W. Ion. 28° 48'; S. lat. 

 7°6', W. Ion. 11°30'; S. hit 33° 30', W. Ion. 11°; S. lat 37° 40', E. Ion. 78° 34'; S. lat. 37°, 

 E. Ion. 5?; S. lat, 39° 54', E. Ion. 41° 30'; S. lat. 29 30', E. Ion. 12°; S. lat. 2.V Ml', E. Ion. 

 23°; S. lat. 12°, E. Ion. 103°50'; S. lat. 11° 15', E. Ion. 103° 50'; X. lat. 10°40,'E. Ion. 110°. 



Liitken unites M. lumps with M. Humboldtii, but since the latter has been as yet found 

 only in the northeastern Pacific, we prefer to hold them apart until specimens from the two 

 oceans have been studied side by side. The scales in lateral line are said to number 37-9. 



