POLYIPNUS. 237 
Argyropelecus affinis sp. n. 
Argyropelecus hemigymnus G. B., 1896, Oc. Ich., Pl. XXXIX., fig. 147. 
DeVIl == 9); A.13. 
In this species the head is longer, the body is less deep, the clavicular 
symphysis is less prominent, the caudal section is of greater comparative 
depth, and the lanterns between the operculum and the caudal are more 
nearly in a continuous series than in A. hemigymnus. The depth of the body 
is about two fifths of the length from the snout to the end of the caudal, 
and the greatest depth of the caudal region is nearly two thirds of that of 
the body. Head length about one third of the distance from the snout to 
the base of the caudal. Spines below the preopercles, the mandibles, at 
the upper ends of the scapulars, and the spine below the ends of the 
claviculars small. The dorsal blade resembles that of the other species of 
the genus; it includes a similar number of spines with slightly protruding 
ends, but has not the serrations between them asin A. caninus. The 
lanterns appear to be about the same in number as on A. hemigymnus but 
differ in arrangement; instead of the three very distinct and widely sepa- 
rated groups between the ventrals and the caudal (the ventral, the anal, 
and the subcaudal group), there is a nearly continuous series. 
Station. Latitude. Longitude. Depth. 
2117 15° 24’ 40” N. 63° 31’ 30” 683 fathoms 
The outlines of this species make a considerable approach from those of 
A. lychius toward those of the genus Polyipnus, which, though unrepresented 
in the collection immediately concerned in this report, has particular 
interest here in connection with the faunal affinities, and from the fact that 
besides the species hitherto recorded from the Indo-Pacific the genus is also 
represented by an undescribed one from the Atlantic. With the description 
of the latter a number of items are added to the diagnosis of the genus. 
PoLyIPNUs. 
Polyipnus Giint., 1887, “ Challenger” Report, Deep Sea Fishes, 170. 
Form intermediate between that of Argyropelecus and that of Ichthyococeus, 
much compressed, tapering in the caudal region; body covered by large 
very thin scales. Eyes large, lateral. Mouth of medium width; maxillary 
