NA TURE 



\August 1 6, 1877 



ocean than it is in the shallowest water. Instead of 300 fathoms 

 or 1,800 feet, which Forbes assumes to be the extreme boundary 

 of submarine life, we must now take 3,000 fathoms, or 18,000 

 feet, and even much lower depths. It may be well to distinguish 

 two zones of depth exceeding that which I have termed "the 

 line of soundings" ; and I would propose the name "abyssal" 

 for depths between 100 and 1,000 fathoms, and "benthal" (from 

 the Homeric word BeVflos, signifying the depths of the sea) for 

 depths of one thousand lathoms and more. 



The first knowledge that I had of the mollusca from the 

 lowest or " bentlial " zone I owe to Dr. Wallich, who kindly gave 

 me a few siiall shells which he got in a sounding of 1,622 

 fathoms in N. Lat. 55" 36', VV. Long. 54° 33', off the coast of 

 Labrador, during his cruise in H.M.S. Bittldog in 1S60. These 

 consisted of undescrihed species of Aclis, Homalogym, and 

 Pliiirotoma, Pletirotoma tenukostata of M. Sars, and fragments 

 of Saxuava rugosa, Linne, and of other shells which are un- 

 known to me. Among these was a dead but perfect specimen 

 of C)-cndla faba, Fabricius, which is a common inhabitant of the 

 laminarian zone in Arctic seas, and may have been voided by 

 a fish or sea-bird. This would account for the occasional 

 occurrence at great depths of other shallow-water shells and 

 fragments. 



I liad the good fortune to take part in the two Porcupine ex- 

 peditions of 1869 and 1S70, and in the Valorous cruise of 1S75 J 

 and the mollusca of tlie Z^/z/z/z/y {1S6S), ChalUnger {x'&iyji,), 

 and Vivingen (1S76) expeditions have been submitted to my 

 inspection. I am consequently enabled to form some idea of 

 the bathymetrical distribution of the mollusca thus obtained, 

 with the aid of my dredging experience for upwards of forty 

 years. 



Perhaps the best way of communicating this idea to others will 

 be by giving the subjoined list of the species of deep-sea mollusca 

 dredged by me in the Valorous, all of which are found at depths 

 exceeding 1,000 fathoms. The range of depth there and else- 

 where in the North Atlantic and Mediterranean will be noted, 

 as well as some geological and other observations. Four only 

 of such deep dredgings were made during the cruise, viz , in 

 1,100, 1,750, 1,450, and 1,785 fathoms. The first two were in 

 Davis Strait, and the other two between Cape Farewell and W. 

 Long. 26° on the return voyage. 



Kellia symmetros, J 



Axinus cycladius, .?. V. Wood 

 A. eumyarius, M. Sars 



A. Croulinensis, J. 



A. incrassatus, J. 



Diplodonta Torelli, J. 



Isocardia cor, L 



Tellina calcaria, Chemnitz ... 



Poromya rotundata, y 

 Pecchioliaabyssicola,A/. Sars 



P. gibbosa, y. 



P. tornati, J 



Neaera striata, y 



N. exigua, y. 



N. notabilis, J. 



N. circinnata, y. 



N. papyria, y 



N. angularis, y. 



SOLENOCONCHIA. 



Dentalium candidum, y. 



D. capillosum, y. 



D. ensiculus, y. 



D. subterfissum, J. 



D. vagina, J. 



I Siphodentalium vitreum, M. 



Sars 



S. affine, M. Sars 



S, Lofotense, M. Sars 

 Cadulus tumidosus, y 



C. Olivi, Se 



C. cylindratus, y 



Gastropoda. 

 Propilidium a.ncy\6Hts,Forl>es 



Puncturella profundi, y. 

 Scissurella crispata, Fleming. 



S. tenuis, J. 



Cyclostrema basistriatum, y 



Acirsa prselonga, y 



Eulima stenostoma, y 

 Natica affinis, Gmclin 



N. sphseroides, y. 



Seguenzia forinosa, y. 



S. carinata, J. 



Cerithium procerum 



Trophon Fabricii, Peck 



Fusus attenuatus, y 



F. Sabini, Gray 



Pleurotoma tenuicostata, M. 



Sars 



P. exarata, Moll 



Cylichna alba, Brown 



Utriculus lacteus, y. 



U. substriatus, y. 



Action exilis, J. 



Scaphander puncto-striatus, 

 Mighels and Adams 



Range ( 

 depth ii 

 fathoms 



488-1750 



30-1750 Coralline-Crag fossil. 



114-1456 

 20-1785 

 40-i7^0j 

 30-1450 Fragment only at greatest 



I depth. 

 40-1785 Fry only at greatest 

 depth. 

 1-1750 Sicilian foisil. Frag- 

 j ments only at greatest 

 I depth. 



1450 1 

 110-1450 



1450 



1785 

 435-1450 



1450 



1450 

 994-1450 



1450 

 290-1785 



410-2435 

 220-1785 

 740-1785 

 1000- 1476 



1450-1785 



150-1750 

 100-1450 

 20-1750 

 UO-1450 



539145° 

 1215-1476 



60-1450 



740-1750 

 7-1095 

 1450 

 50-1095 

 994-1450 

 50-1456 

 5-1100 



1750 

 325-1785 



690-1095 



400-1450 



35-1450 



690-1215 

 100-1450 



Fragments only at great- 

 est depth. 

 Fragment only. 

 Fragment only. 



Fragment only at greatest 

 depth. 



Fragment only 

 I 'alorous. 



Sicilian fossil, as Rostri- 

 septa parva, Seg. 



Sicilian fossil. 



Sicilian fossil. 



Fragments only at great- 

 est depth. 



A young shell. 



Sicilian fossil, as S.mono- 

 cingulala, Seg. 



C. Danielseni, Friele. 

 Fragment only at greatest 

 depth. 



Fragments only at great- 

 est depth. 



40-1622 

 5-1230 



7-1400 Sicilian fossil. 

 1443-1450 Fragment only at greatest 

 depth. 

 1750 

 49-1450 Sicilian fossil. 

 26-1450 Sicilian fossil. Frag- 

 I ment only at greatest 

 depth. 



Besides undeterminable fragments of other and probably new 

 species. 



