ALEPOCEPHALOIDS. 283 
ALEPOCEPHALOIDS. 
This group contains the family Alepocephalide and several types, Ronde- 
letia, Anomalopterus and Cetomimus, of questionable relationships to the 
family and to one another, probably representing different families, but placed 
here until more is known about them. Approximately the ascertained horizon- 
tal distribution of the Alepocephalida extends in the Atlantic, including the 
Mediterranean, from ten degrees of south to fifty degrees of north latitude, 
in the Pacific from the equator northward forty-eight degrees, and in the 
Indian Ocean from Australia northward. The least depth that has been 
reported for any of the species is 200 fathoms and the greatest is 2949. 
The greatest range for an individual species is that of Alepocephalus rostratus 
Risso, off the north African coasts, from data secured by expeditions sent 
out by the French government; this species was taken at various stations 
between a depth of 453 fathoms and one of 1998, a vertical range of 1545 
b] 
fathoms. Between Japan and Australia the “Challenger” researches 
gave the family a range extending from a depth of 345 to one of 2150 
fathoms; and in the northern portions of the Indian Ocean the “ Investiga- 
tor” secured specimens at various depths, from 240 dewn to 1000 fathoms. 
There is less uncertainty regarding the habitat of this family than in 
respect to that of some of the others. Structure, blackness of integument, 
food, and the condition of the specimens on arrival at the surface all favor 
the conclusion that these fishes dwell close to the bottom, hundreds of 
fathoms below the surface. - The large eye is a distinguishing feature of the 
Alepocephalid and its possession must be regarded as proof of the presence 
of light either in the bodies of the other inhabitants of the sea bottom, 
fellows, enemies, prey, etc., or in the medium in which the family lives, one 
or the other or both. In the absence of luminous organs, except, it may be, 
in Xenodermichthys, the principal dependence for recognition of others of 
the same species at a distance, probably lies in ability to recognize similarities 
and differences in form, outlines, positions of fins, and the like, and these are 
made visible by the luminosity of the integuments of the object or by the light 
in the water around it, presumptively by both of them. The surfaces of these 
fishes are more or less phosphorescent, but aside from this it would appear 
that the large eye, with the lack of special light organs and of special devel- 
opments of the organs of touch, should be taken as evidence that the Alepo- 
