DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 73 



dorsal base is twothirds that of head. Origin of ventral under tenth scale of lateral line; 

 it does not reach to vent. Pectoral short, its length nearly two-thirds that of head. Adipose 

 dorsal present; 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 

 that of head. Caudal is rather small and moderately forked. 



Mediolateral photojthores 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 rootof lastray of anal. Xumber of superanals S+C. 



In most of the specimens of M. opalinum examined , the or S scales on the top of the 

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



MYCTOPHUM PHENGODES, (Lutken), Gooi>k mid Bean. 



ScoiH'his phengodes, Lutken, Spolia Atlaiitica, ii, 1892, 253, Fig. 11. 



A species resembling in general appearance our Myetophnm piiiicfatHm, 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 nearer to the row of mediolateral photophores than to the 

 anterolateral. This formhati, aahi 31. puncfatiDn, 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 Liltken, but which seems to us of less importance than the 

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



liadial formula: D. 12; A. 21; L. lat. .38. 



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



MYC'TKPIIUM IIITXIBOLDTII (Rlsso). (Figure S2.) 



Gasteropelecus HiimboliUi, Risso, Ic.th. Nice, 358, pi. 10, fig. 38. 



Scopelus Humboldti, RiGiO, Mem. Accad. Sc. Torino, xxv, 1820, 266, pi. ID, lig. 2.— Uimtueu, Cat. Fish. Brit. 

 Mus., V. 407.— GiQLiOLl, Elenco, 100. 



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

 Least depth of tail two-flfths 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 iiosterior margin of 

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

 file descending in strong curve. Maxillaiy reaches nearly to angle of preoperculum, 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 last ray before vertical from origin of anal. 

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

 phores, 2; anterolaterals, 2; ])osterolateral, 1, (over break in anal series) which, as in M. 

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

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

 (jodcx. Superanals- 7-9 -f 4-9. Radial formula: D. 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 spei-imen (No. 43772, TJ. S. N. M.) upon the surface, at 7 p. m., from station 2727, 

 in S(<°3r>' N. lat., 74° 03' 30" W. Ion., and also a very fine specimen (No. 43773, TJ. S. N.M.) 

 from station 2724, in 30^47' N. lat., 73= 2.5' W. Ion., at a depth of 1,641 fathoms. 



Liitken had a number of specimens of M. Humboldtii {op. cit., p. 254, fig. 2) from the 

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

 70 C, W. Ion. 113 30'; S. lat 33^ 30', W. Ion. 11^; S. lat 37° 40', E.lon. 78° 34'; S. lat. 37°, 

 E. Ion. 50; S. lat. 39° 54', E. Ion. 41° 30'; S. lat. 29° 30', E. Ion. 12°; S. lat. 25° 40', E. Ion. 

 230 ; S. lat. 12°, E. Ion. 103'^ 50' ; S. lat. 11° 15', E. Ion. lOS^ 50' ; N. lat. 10° 40,' E. Ion. 110°. 



Liitken unites M. hoops with .1/. EumholdUi. 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. 



