188 PROCEEDINGS OF THE MALACOLOGICAL SOCIETT. 



Mr. E. A. Smith, and the Rev. R. B. Watson, have taken part in this 

 great work. 



Describinjr the dredging operations, Sir Wyville Thomson writes : 

 '' The three most interesting species brought home by the 

 ' Challenger ' were Terebratula Wyvillt, Davidson ; TcrchratuUna 

 Wyvilli, Dav. ; and Discina Atlaiitica, King. Terebratula Wyvilli 

 was obtained at six different stations, and appears to abound over a 

 wide geographical area, at depths varying from 1035 to 2900 fathoms; 

 the greatest depth whence any living Brachiopod has been brouglit up." 



Of Terehratulina Wyvilli (the largest species of the genus hitherto 

 discovered, either recent or fossil) one specimen only was dredged, on 

 the 25th March, 1873, off Culehra Island, to the north-west of St. 

 Thomas's in the West Indies, at a depth of 390 fathoms. Discina 

 Atlantica was brought up at six or seven different stations, and is a 

 widely-spread abyssal form. 



AVliile dredging and trawling in very deep water off Uermuda, 

 Wyville Thomson mentions taking several species of Trochus and 

 other Molluscs in 1075 fathoms, and Crania at 435 fathoms. 



Of all the Molluscs obtained during the expedition, the most 

 valuable was the unique specimen Guivillea alahastrina (alt. 6f in., 

 diam. 3 in.), a pure white alabaster Volute, of exceptional form, 

 dredged from a depth of 1600 fathoms in the Southern Ocean. 



Mr. Edgar Smith, in his General Remarks on the LamcUibi'anchiata 

 ("Challenger" Reports — Zoology — vol. xiii. part 1, p. 3), is struck 

 by the small number (only about 500 species) obtained, and that they 

 arc represented by very few specimens, there being of many of them 

 but a single, or a few odd valves, often badly preserved. 



By far the most special interest attaches to the deep-water forms, 

 one of which was obtained from about 2900 fathoms in the mid- 

 North Pacific. . This, a small fragile shell, which has been named 

 Callocardia (or Fesicomya) Pacifica^ is almost ideiitical with a second 

 species [C. Atlantica) dredged from 1000 fathoms off the Azores; and 

 a third species, C. Adamsii, obtained S. W. of Sierra Leone from a depth 

 of 2450 fathoms. 



Mr. Edgar Smith not only gives a list of species occurring in widely- 

 separated geographical localities, but also in extremely varied bathy- 

 metric positions ; Lima multicostata being found living in 2 and in 

 1075 fathoms depth ; Pecten ritreus in 140 and at 700 fathoms ; Area 

 pteroessa in 390 and 2050 fathoms ; Venus mesodesma (a shore species) 

 dredged in 1000 fathoms; Pecten PhiUppi and Dacryditim vitreum 

 both obtained in less than 40 fathoms, and also from 450 and 1000 

 fathoms. 



A large number of species, Mr. Smith thinks, are equally well 

 adapted for living in deep or in shallow water, and their shells appear 

 to be very little affected by the difference of the depth or the nature 

 of the bottom. Dr. Davidson has also mentioned the same thing in 

 regard to the Brachiopoda; one species [Terehratida vitrea) ranging 

 from 5 to 1456 fatlioms. 



Mr. Edgar Smith points out that the absincc of light, however, 

 tends to produce shells without colour, and that the deep shells are 



