134 THE DEPTHS OE THE SEA. [chaf. iv. 



The northern species above referred to are 34 in num- 

 ber, and include Dacridiwm vitreum. Nucula pumila, 

 Lcda lucid a, L.Jeigicla, Verticordia abyssicola, Necera 

 jugosa,N. obesa, Tectura fulva> Fissurisepta papilloma, 

 Tor ell i a vestitcbyPleurotoma turricula, Admete viridula, 

 Cylichna alba, Cylichna oca/a, Jeffreys n. sp., Bulla 

 conulus, S. Wood not Deshayes (Coralline Crag), 

 and Scaphander librarius. Leila lucida, Ne&rajtigosa, 

 Tectura julva, Fissurisepta papulosa, Torellia cestita, 

 as well as several other known species in this dredging, 

 are also fossil in Sicily. Nearly all these shells, as 

 well as a few small echinoderms, corals, and other 

 organisms, had evidently been transported by some 

 current to the spot where they were found ; and they 

 must have formed a thick deposit similar to those of 

 which many tertiary fossiliferous strata are composed. 

 It seemed probable also that the deposit was partly 

 caused by tidal action, because a fragment of Melam- 

 j)i(s mi/osolis (a littoral pulmonibranch) was mixed 

 with deep-water and oceanic Pectinibranchiates and 

 Lamellibrancliiatcs. None of the shells were Miocene 

 or of an older period. 



"This remarkable collection, of which not much 

 more than one-half is known to conchologists, not- 

 withstanding their assiduous labours, teaches us how 

 much remains to be done before we can assume that 

 the record of Marine Zoology is complete. Let us 

 compare the vast expanse of the sea-bed in the North 

 Atlantic with that small fringe of the coast on both 

 sides of it which has yet been partially explored, and 

 consider with reference to the dredging last men- 

 tioned what are the prospects of our ever becoming 

 acquainted with all the inhabitants of the deep 



