among the Shetland Isles. 253 



bella nana, Pleurotoma brachystoma, Cylichna acuminata, Philine 

 quadrata, and P. nitida. 



3. Habits of Animals. — Species which were supposed to in- 

 habit shallow water only were found living at considerable 

 depths. In this category may be mentioned Natica catena, 

 which was dredged alive in from 40 to 50 fathoms. Capt. 

 Thomas informs me that he also dredged this species in the 

 Orkneys living at the same depth. A dead specimen of Stilifer 

 Turtoni was procui'cd with Natica catena. Bathymetrical con- 

 ditions are not of so much consequence to the Mollusca as a 

 suitable habitation and a good feeding-ground. We had the 

 good fortune of dredging in 170 fathoms — a greater depth 

 than had been previously explored in the British seas. This 

 was about forty miles N.N.W. of Unst. The ground was 

 stony intermixed with patches of sand. The greatest depth 

 recorded as having been dredged in our seas was 145 fathoms, 

 by Admiral Beechey, off the Mull of Galloway. The following 

 is a list of the Mollusca which I examined from our dredging 

 in 170 fathoms : — 



Living. — Brachiopoda : Terebratula cranium, young ; T. caput- 

 serpentis, young; Crania anomala. Conchifera : Anemia ephip- 

 pium, young ; A. patelliformis, var. striata ; Lima subauriculata, 

 young; Leda pygmcBa ; Montacuta substriata, on Spatangus meri- 

 dionalisl ; Venus ovata ; Lucinopsis undata, young; Saxicava ru- 

 gosa. SoLENOcoNCHiA : Dentalium entalis, v&r. anulatu. Gas- 

 tropoda: Trochus occidentalis ; Eulima bilineata ; Natica Mon- 

 tacuti ; Trophon Barvicensis. 



Dead. — Conchifera : Pecten septemradiatus, a fragment ; P. 

 tigrinus, ditto ; P. similis, a single valve ; Crenella decussata, frag- 

 ments ; Nucula nucleus, single valves ; N. tenuis, ditto ; Leda mi- 

 nuta, a single valve ; Limopsis aurita, small but fresh single valves; 

 Area pectunculdides, single valves ; Lucina borealis, perfect ; Axinus 

 Croulinensis, single valves ; Cardium fasciatum, ditto; C. minimum, 

 ditto ; Astarte sulcata, ditto ; Venus lincta, ditto ; Tellina balaus- 

 tina, a fragment ; Psammobia Ferroensis, ditto ; Mactra solida, var. 

 elliptica, single valves ; Scrobicularia prismatica, a fragment ; 

 Thracia papyracea, var. villosiuscula, young ; Necera cuspidata, a 

 fragment. Gastropoda: Tectura fulva, var. albula ; Pi'opilidium 

 ancylo'ides ; Emarginnla fissura ; Trochus amabilis, young; T. mille- 

 granus, ditto; Tiwritella terebra, var. nivea ; Natica Alderi ; Tri- 

 chotropis borealis ; Buccinopsis Dalei, a fragment ; Fusiis gracilis, 

 young; F. propinquus, ditto; Defrancia teres; D. linearis, var. 

 cequalis, a fragment ; Pleurotoma costata, ditto ; Cylichna alba, 

 ditto. Pteropoda : Spirialis retroversus ; Clio or Cleodora cuspi- 

 data, a fragment. 



Of these species sixteen were living, and thirty-eight dead — 



