Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/242

128 the opportunity of recording the opinion of another distinguished naturalist, Mr. Gwyn Jeffreys, who has made European conchology his especial study, and has particularly worked out the deep-sea fauna with a view to a comparison with fossil species upon this question. We have visited the Crag district together; and he has examined all the more important Crag collections, while with the same object in view he has also extended his researches to the Pliocene collections of the Continent. The special results of his elaborate inquiry will be found in the tabular list, pp. 137-146. The list of Coralline-Crag Mollusca so revised gives a total of 316 species, of which Mr. Jeffreys considers 264 to be living and 52 extinct, thus giving a percentage of 84 recent, and apparently only of 16 extinct species.

Of these 265 living species of Mollusca, Mr. Jeffreys has determined 185 to be still living in the British seas, and 80 to be species living now only in extra-British seas. Of the latter, 14 species live in northern seas only, 65 in southern only, and 1 lives in both northern and southern seas. Dividing the living species into zoological provinces, I find their distribution is as under:—

Bivalves. Univalves. Total. Peculiar.

Arctic 19 15 34 2 Scandinavian 75 60 135 0 British 101 84 185 2 West European 90 81 171 1 Mediterranean 103 97 200 17 Mid-Atlantic 49 50 99 4 Deep Atlantic 41 51 92 10

Of the 5 species of Brachiopods in the Coralline Crag, 1 only is extinct. Two are British species with an extensive range. Mr. Gwyn Jeffreys has dredged the Argiope cistellula in from 20 to 80 fathoms water; and the Terebratulina caput-serpentis ranges from the shore to 632 fathoms. The Discina atlantica has been dredged in the deep Atlantic (7560-13,500 feet). The Lingula Dumortieri has been dredged in the seas of Japan. As a rule, Brachiopoda may be considered to indicate deep water.

Bryozoa.—According to Mr. Busk, there are not less than 95 species of Bryozoa found in the Coralline Crag; 30 of these species are now living, and 65 are extinct. Of the former, 26 still inhabit the British seas; and of the other four, 3 are found on the west coast of Africa and at Madeira, and 1 is probably living in the Australian seas. Of the 26 British species, 9 have a southern range, some as far as Patagonia and the Falkland Islands. There is one remarkable exception to this southern character; the Retepora Beaniana has been found on the coast of Norway by Mr. M. Andrew, and in the Arctic sea by Sir Edward Belcher. Mr. Busk considers it to be a wholly northern