Home new and pecidtdr Mollusca. 329 



cctast.s of United States, from low-water mark to 50 fms. 

 (Mi^lids and others) ! Spitzber<^en (Torell) ! Iceland (Morch, 

 \'crkruzen) ! Norway, 5-2/30 fms. (G. O. Sars and others) ! 

 ' Li^'-htnini:;' Expoditidii, 170 fins. ' Porcnpinc ' E.\[)cdltion, 

 18()1>, off ithe west of Ireland, 420 fms. ; north of the Hebri- 

 des, 203-345 fms. 



There are at least fonr varieties, viz. oiohicca of Miglielsaud 

 Adams (not of Hinds), and CJ/Iindracea, Bcckii, and livida of 

 MiiUer (ex typ.), all published in 1842. P. Beckii of Reeve, 

 in Cumin<^"s eollection, is a very different and tropical species. 

 Specimens from 57 fatiioms are of a pale colour, and those from 

 deeper water are white. Allied to the variety livida is P. 

 gi(jas of Beck, which is Bela hwigata of Dall, and probably 

 P. schantaricum of Middendorf!'. Reeve renamed the present 

 species P. groenlandica and P. rugulatus : he supposed that it 

 was the Defrancia suturalis and D. rugidata of MoUer ; but 

 the latter gave no such names to any of his sjiccies. Appa- 

 rently not P. hicarinata of S. V. Wood. 



Pleurotoma rubescens, JefFr. 



Holsteinborg, 10 fms. (a single but living specimen). 

 Described in Proc. Roy. Soc. vol. xxv. p. 183. 



Pleurotoma decussata, Coutliouy. 



Pleurotoma decussata, Couth, in Boston Joum. Nat. Hist. ii. p. 183, 

 pi. iv. f. 8 (18.3U). 



Godhavn, 5-20 fms. ; Waigat Strait, 15-25 fms. ; Station 3, 

 100 fms. ; 5, 57 fms. Greenland (Moller, Morch) ! N'.E, 

 America, from the Gulf of St. Lawrence to Cape Cod, 10- 

 64 fms. ' Porcupine ' Expedition, between the north of Scot- 

 land and the Faroes, 560 fms. 



I have now been able to ascertain that this species is the 

 same as Defrancia viridula of Moller (1842) ; and I was 

 therefore wrong in supposing that the latter was not American 

 (see Proc. Roy. Soc. vol. xxv. p. 189). It is the P. scalaris 

 and P. leiicostoma of Reeve, who imagined that Vahl had de- 

 scribed them under the names of Defrancia scalaris and D. 

 reticulata ; but Vahl did n(jthing of the kind. I would not 

 have noticed Reeve's numerous mistakes if Morch had not 

 recognized his so-called species. 



Pleurotoma tenuicostata^ M. Sars. 

 nuicostata, Sars in Vid. Selsk. Forhanc 



Station 12, 1450 fms. ' Lightning ' Expedition, 500 and 



Pleurotoma tenu{costat<i, Sars in Vid. Selsk. Forhandlinger for 1868, 

 p. 2r>{). 



