THE BARENTS SEA 127 



numerous, first of all Onchidiopsis glacialis, Trochus occidentalis, some 

 species of Velutina ( V. haliotoides, V. lanigera, Undata g. expansa, Columella 

 rosacea, Marsenina micromphald) and others. 



On sand fades a more or less abundant life on the sublittoral develops only 

 with silting. Life is very poor on large-grain sand and gravel. Only the so-called 

 Dentalium sand (40 to 69 m), consisting mainly of finely ground mollusc 

 shells, is abundantly populated by a rich fauna of molluscs (up to 60 species) 

 Dentalium entails and species of the genera Bela, Philine, Solariella, Cylichna, 

 Astarte, Cardium, Mactra and others. Other groups of animals are rather 

 scantily represented here. 



An abundant fauna of polychaetes, echinoderms and molluscs grows on 

 silty sands at shallow depths (4 to 1 5 m). Among the first-mentioned the most 

 frequent here are Ophelia limacina, Nephthys ciliata, Harmothoe imbricata, 

 Nychia cirrosa and Travisia forbesi ; of secondary importance are Chiridota 

 laevis, Strongylocentrotus droebachiensis and Asterias rubens. The molluscs 

 most frequently found include Nucula tenuis, Cardium ciliatum, Leda pernula, 

 Astarte banksi, A. borealis and Pec ten islanidcus, and of the crustaceans 

 Ну as araneus v. hoeki, Eupagurus pubescens and others. 



The fauna of the facies of large-size shell gravel at shallow depths (20 to 

 30 m) is not typical and on the whole very poor. Much deeper (50 to 140 m) 

 finer coquina accumulate, giving shelter to an extremely abundant fauna, 

 consisting mainly of sponges, polychaetes, bryozoans, echinoderms and crusta- 

 ceans (amphipods). The Porifera are especially well represented here (up to 

 26 species) : in the first place — Phavellia bowerbanki, Geodia baretti, Grayella 

 pyrula, Trichostemma hemisphaericum, Tentorium semisuberites, Tedania 

 suctoria, Tethya lyncurium, and others. Among the polychaetes Onuphis 

 conchylega, Glycera capitata, Maldane sarsi, Nicomache lumbricalis, Nereis 

 pelagica, Leodice norvegica, Protula media, Placostegus tridentatus, Flabelligera 

 affinis, Filigrana implexa, Lumbrinereis fragilis, Thelepus cincinnatus, Sabella 

 fabricii, Nephthis ciliata, Brada granulosa and others should be noted. 



Of the Sipunculoidea there are many Phascolion strombi. The bryozoans are 

 represented here by Flustra membranaceo-truncata, Fl. securifrons, some 

 species of Retepora, Idmonea atlantica, Menipea ternata v. gracilis, Bugula 

 murrayana, and others. 



Of the echinoderms the most frequent here are young Heliometra quadrata, 

 and Cribrella sanguinolenta, Pteraster pulvillus, Solaster endeca, Ophiocantha 

 bidentata, Ophiopholis aculeata, Ophiura sarsi, Strongylocentrotus droe- 

 bachiensis, and others. Haploops tubicola, Socarnes vahlii, Pardalisca cuspi- 

 data and others are the characteristic amphipods. Other groups are scarcer 

 on coquina. 



The fauna of the facies is both peculiar and rich. The clayey-sandy mud of 

 shallow depths (12 to 60 m) is inhabited by numerous burrowing fauna of 

 polychaetes, holothurians, molluscs, Cumacea and amphipods. The main 

 polychaetes are Pectinaria hyperborea, Nephthys ciliata, Brada villosa and 

 Scoloplos armiger. There are huge numbers of Myriotrochus rinki and 

 Chiridota laevis among Holothuriae. As for the other echinoderms there are 

 many Ophiura sarsi and Strongylocentratus droebachiensis. 



