Dr. A. Giinther on Additions to the British Fauna. 289 
rarely to fall into the hands of a naturalist, generally to be cut 
up as bait for the lobster-pot. The British species of Lepio- 
cephalus is not better known than the allied forms from the 
Mediterranean and tropical seas. Others, like Centrolophus, are 
known from single examples only. Their development, as well 
as that of many of the more common forms which spawn in the 
open or deep sea, is perfectly unknown. 
In seeking information concerning this part of the British 
fauna, we are not hunting after a shadow: there is evidence 
enough to show that the depths of the British seas are inhabited 
by a fish-fauna very‘different from that of the coasts, and that 
this fauna is composed of two elements—first, of those which 
may be regarded as indigenous, and, secondly, of such forms as 
are frequently, perhaps constantly, carried by currents from 
-more southern parts of the Atlantic northwards, even to the 
coasts of Norway (Antennarius, Batrachus, Beryx)—not to men- 
tion those fishes which by their strong power of swimming are 
enabled to reach our shores in their migrations, as Ausonia. 
The causes of our incomplete knowledge of these fishes are 
evident : zoologists were either not aware of the existence of 
such a fauna, or satisfied with the stray specimens thrown in 
their way by accident; while the difficulties surrounding the 
examination of the deep-sea fishes are so great as to render all 
progress in attaining to a knowledge of them extremely slow. 
Still it may be hoped that, after the attention of naturalists has 
been directed to the subject, no opportunity will be lost of 
advancing it. 
Such an opportunity occurred to Mr. J. Gwyn Jeffreys, who, 
during his exploration of the marine invertebrate fauna of the 
Hebrides, preserved the specimens of fishes which were brought 
up in the dredge from a depth of from 80 to 90 fathoms. Small 
as the number of specimens is, the result of their examination 
proved to be most interesting and satisfactory, inasmuch as they 
belong to four species new to the British fauna, two being new 
to science, viz. Ammodytes siculus (Swains.), Motella macroph- 
thalma (sp. n.), Callionymus maculatus (Bonap.), and Gobius 
Jeffreysii (sp. n.). On former occasions I have pointed out that 
the geographical range of deep-sea fishes appears to be extended 
in proportion to the vertical depth inhabited by them, and that 
they are either distinguished by an increased size of the eye to 
collect as many rays of light as possible, or by a rudimentary 
condition of that organ, as is the case in fishes inhabiting caves. 
This is in some measure verified by the species collected by Mr. 
Jeffreys, which, however, it must be remembered, inhabit a 
much less depth than Regalecus, Plagyodus, &. Two of them 
(Callionymus maculatus and Ammodytes siculus) were previously 
known as occurring in the Mediterranean; and the eyes of three 
