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 Lepto- 

 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, Benjx) — 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- 

 ihalma (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, &c. Two of them 

 {Callionymus maculatus and Ammodytes siculus) were previously 

 known as occurring in the Mediterranean ; and the eyes of three 



