1876.] Biology of the 'Valorous' Cruise j 1875. 



187 



MOLLTJSCA. 



The total number of marine species procured during the ' Valorous ' 

 cruise was 181, viz. 122 in Davis Strait, and 59 in the North Atlantic, 

 besides fragments of several undetermined species. The most complete 

 and modern list of Grreenlandic species is that which Dr. Morch, the 

 eminent conchologist of Copenhagen, prepared for the Manual of ' The 

 Natural History, Greology, and Physics of the Arctic Eegions, 1875/ 

 This Manual was published by authority of the Lords Commissioners of 

 the Admiralty for the use of the North-Polar Expedition. Dr. Morch's 

 list gives 155 marine species from G-reenland, after deducting doubtful 

 species and varieties. I am now enabled to add to that list 33 species, 

 viz. 21 already described, and 12 undescribed or new. These last, with 

 one exception (Pleurotoma ruhescens), were from depths exceeding 1000 

 fathoms. I obtained altogether from Davis Strait and the North Atlantic 

 no fewer than 37 undescribed species (Brachiopoda 2, Conchifera 16, Sole- 

 noconchia 7, Gastropoda 11, Pteropoda 1, Cephalopoda 0), all except the 

 Pleurotoma from great depths. The only land-shell which occurred to me 

 in Greenland was Vitrimc ]pellucida, Mliller, = V. angelicce (Beck), MoUer, 

 which is a native of all the four old quarters of the globe. Several species 

 from deep water were familiar to me from my dredgings in the ' Porcu- 

 pine ' off the west of Ireland and in the Bay of Biscay, as well as from 

 the newer tertiary deposits in Sicily — thus showing a range of distribu- 

 tion from 56° to 38° N. lat., or between 1200 and 1300 miles. One of 

 the most remarkable instances of such distribution, both in space and 

 time, consisted in the rediscovery in comparatively high latitudes of two 

 exquisite and peculiar species which cannot be referred to any known 

 genus, and for which I will propose the name of Seguenzia, in honour of 

 my friend Signer Seguenza, Professor of Geology and Palaeontology at 

 Messina. The genus evidently belongs to the Solarium family, but is 

 distinguished by having a broad and deep open furrow (rather than a 

 cleft) in the upper part of the last whorl. I have three species, all 

 undescribed (S.formosa, S. elegans, and carinata), the first of which 

 has no umbilicus, the other two being deeply umbilicated. The newer 

 Tertiaries of Sicily also contain several other species of northern Mol- 

 lusca in a fossil state which do not appear to inhabit the Mediterranean. 

 Some of these (e. g. Mya truncata, Saocicava Norvegica, and Buccinum 

 undatum) are comparatively shallow-water species ; and as their trans- 

 port or migration southwards cannot be accounted for by the action of 

 deep submarine currents, it is difficult to conceive how they could have 

 lived in that part of the Mediterranean where Sicily now stands, unless 

 the climate of that region had changed in the same way as must have been 

 at one time the case in Great Britain. Possibly the North Pole may 

 formerly have been placed in Scotland ! 



The consideration of the Mollusca in Davis Strait gives rise to 



