Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/368

Rh Such can scarcely be regarded as true members even of our southern-most ichthyological fauna, of which are rather characteristic Zeus aper, Trigla pini, Pagellus centrodontus, Cepola rubescens, Atherina presbyter, Blennius ocellaris, Cantharus griseus, Trygon pastinaca and Clupea pilchardus; the last, though found on most parts of our coast, being only prevalent in the south-west.

In like manner our northenmost ichthyological province includes at its extremity occasional visitants which there reach the south-eastern limit of their range, as Cottus quadricornis, Scorpæna Norvegica, Gymnetrus arcticus, Scymnus borealis, Chimæra monstrosa and Brosmus vulgaris; the two latter are constant and the last an abundant inhabitant of the Zetland Seas. Certain species also, which though they range throughout our seas, are only abundant in the north, may be regarded as true members of this province—as Anarrhicus lupus, Merlangus carbonarius, Cyclopterus lumpus and Myxine glutinosa, and even the cod (Gadus Morrkua), and the herring (Clupea harengus).

The assemblage of fishes, of which the British Seas may be regarded as the centre, is partly composed of species which are not known elsewhere, and therefore essentially of a British type and partly of such as are characteristic of the seas bounding the shores of the central portion of Western Europe, and which may be styled the Celtic region. That great extension of sub-marine land surrounding the British Isles, a map of which has been given by Sir Henry De la Beche, in his 'Researches in Theoretical Geology' (where the important bearing of such a tract on many geological phenomena is admirably explained), may be regarded as the true country of the Celtic sub-marine fauna, of which such fishes form a part. Leptoœphalus Morrisii, Lepadogaster cornubiensis, Liparis Montagui, Clupea alba, and Raniceps trifurcatus are examples of the first or British division of this type, whilst a host of species, including Trigla gurnhardus, Cottus bubalis, Aspidophorus cataphractus, Scomber scomber, Blennius pholis, Crenilabrus tinca, Merluchius vulgaris, Lota molva, Solea vulgaris, Pleuronectes maximus and rhombus, Anguilla conger, Ammodytes tobianus and lancea are well-known members of the second.

To the oceanic type belong such of our occasional visitors as have very wide ranges, as Naucrates ductor (the pilot-fish), Echineis remora (the sucking fish), Trichiurus leptura, Xiphias gladius (the sword fish), Scomber pelamys (the bonito), and many of our sharks.

The marine Articulata of the British Seas have been so little studied, so far as their distribution is concerned, that it is difficult to give even the slightest sketch of it. Materials, however, are gradually accumulating, and so far aa the Crustacea are concerned—the division most importtant to the geologists, sedng that their remains are often preserved in