GADOIDS. 179 
The amount of specializing modification undergone by bathybial Gadoids 
is less comparatively than that seen in groups like the Pediculates or even 
the Brotuloids. Special light producing organs have not yet. been discov- 
ered; though probably the lateral system is more or less luminous in a 
number of the genera. No species deprived of sight are known as yet; the 
eye generally is large and well developed. Such modifications as exist are 
most apparent in the lateral system and in its surroundings on the skull, 
where the changes do not differ in any noticeable extent or character from 
those- obtaming on most other deep sea fishes, except perhaps in case of 
Phycis regius Walb., on which the aural and the occipital portions of the 
system are considerably differentiated, in connection with electric functions, 
this being the species capable of giving off a very perceptible discharge as 
recorded by Prof. A. Agassiz, 1888, in the Three Cruises of the “Blake,” IL, 
p. 23. The system in this species and others of the group has been worked 
out as far as was possible from the alcoholie specimens and is figured on 
Plate LX XXI. fig. 2, Plate LXXXII., and Plate LXXXIII. fig. 1. Fila- 
mentary developments no doubt serving as tactile organs occur on many 
species, but neither in such extent nor condition as should serve to separate 
the Gadoid much from other deep sea forms, or, for that matter, from 
various pelagic or shoal water species, 
The specimens in this collection were generally taken from localities in 
which the bottom was muddy and in temperatures the average of which is 
about 48.2 degrees Fahrenheit, or of which the recorded extremes were 
57.3 degrees and 36.8. The greatest range noted for a single species is that 
of Phyciculus longipes, 56.2 to 389 degrees, which species ranged vertically 
from the 127th fathom to the 695th. This range in depth is much ex- 
ceeded in the group by species of the northwestern Atlantic, Antimora rola 
G. B., from a depth of 506 to one of 1454 fathoms and Lemonema melanurum 
G. B., taken at a depth of 208 fathoms and downward to that of 1437, which 
gives these species vertical ranges of 1128 and 1259 fathoms respectively, 
the greatest in the family and each more than a mile. In the case of these 
fishes as in that of others it is very evident that of the two, temperature 
and pressure, it is temperature and not pressure that is the determining 
factor in vertical distribution. This is shown by Antimora viola captured 
’ 
by the steamer “ Albatross” at some thirty different stations for which 
both depth and temperature of the bottom are given. The depths vary 
more than a thousand fathoms while the temperatures corresponding to 
