REPORT ON THE LAMELLIBRANCHIATA. 



Area {Barbatia) corpulenta, 



Mytilus edulis, 

 Mytilus magellanicus 



Modiolaria cuneata, 

 Lima squamosa, 



Lima lata, . 



Lima multicostata, 



Lima goliaih, 



Lima loscomhii, 



Pecten vitreus, 



North-East Australia, iii 1 400 fathoms ; south of 



Amboyna, in 200 to 3G0 fathoms; Mid Pacific, in 



2425 fathoms; and near the Lshind of Juan Fernandez, 



in 1375 fathoms. 

 Cosmopolitan. 

 Falkland Islands, Kerguelen Island, and Fiji, all in 



shallow water. 

 Port Jackson and the Cape of Good Hope, shallow water. 

 Tenerife, in 70 fathoms, and the Philippine Islands, in 



10 fathoms. 

 St. Paul's Eocks, Atlantic, in 104 fathoms, and 



Philippine Islands, in 82 fathoms. 

 Port Jackson, in 2 to 1 8 fathoms ; Tongatabu, in 1 8 



fathoms ; and off Bermuda, in 1075 fathoms. 

 South Japan, in 775 fathoms, and South Patagonia, in 



245 fathoms. 

 A British species ; from the Azores, in 450 fathoms, and 



Tristan da Cunha, in 100 to 150 fathoms. 

 West coast of Patagonia, in 140 to 400 fathoms ; South 



Japan, in 345 fathoms ; and Philippine Islands, in 



100 to 700 fathoms. 



A perusal of the above will show that some of the species were obtained not only at 

 widely distant localities, but also at very different depths. Venus mesodesma (a shore 

 species) was dredged in 1000 fathoms. Area pteroessa in 390 and 2050 fathoms, Lima 

 midticostata in 2 and 1075 fathoms, Pecten vitreus in 140 and 700 fathoms, Necera ohesa 

 in 40 and 1000 fathoms, Ervilia castanea in 70 and 1000 fathoms, and Dacrydium 

 vitreum and Pecten pldlippii, both of which have been obtained in less than 40 fathoms, 

 were hauled up respectively from 1000 and 450 fathoms. I might multiply examples of 

 the different ranges in depth at which various species have been obtained by the 

 Challenger and other expeditions, but those which I have cited are sufficient to show 

 that the same species is equally well adapted for living in deep or shallow water, and, 

 as far as I have noticed, the shells appear to be very little aflfected by the difierenee 

 of the depth or the nature of the bottom.^ As a rule, very deep-water "benthal" 

 species certainly have a tendency to be without colour, and of thin structure, no 

 doubt resulting from the absence of light, the difficulty of secreting lime, the scarcity of 

 food, and other unfavourable conditions of existence. 



1 Mr. Davidson has also mentioaed instances of Bracliiopods " capable of existing at a great variety of depth," one 

 species (Terebratuki vitrea) ranging from 5 to 1456 fathoms. Zool. C'liall. Kxp., part i. p. 6, 1880. 



