958 REPORT—1850. 
Jeffreysia opalina, Rissoa lactea and Murex corallinus ; or oceanic forms of 
Tanthina, Hyalea and Spirialis; or species probably of arctic origin, ex- 
tending only to our north-eastern coasts, as Fusus norvegicus and Turtoni, 
Natica Kingii, Hypothyris psittacea and Goniaster equestris. The number 
of doubtful or not sufficiently investigated forms is also very small. A con- 
siderable number of genera have no, or few, representative members in the 
Scottish and English columns of western sublittoral species ; these are either 
extra-limital, as Hyalea, Haliotis and Hypothyris; or excessively rare in 
our seas, as Avicula, Stylifer, Cidaris and Astrophyton ; or oceanic, as Tan- 
thina and Spirialis ; or wholly or mainly littoral, as Littorina, Otina, Cono- 
vulus, Truncatella, Jeffreysia, Skenea (proper), Patella, Pleurobranchus, 
Teredo, Xylophaga, Petricola, Venerupis, Ceratisolen, Turtonia, Galeomma, 
Mytilus, Asterina. In Odostomia we have a genus which is not fairly re- 
presented on account of the excessively critical character of its species. Five 
genera of Gasteropoda, three of Lamellibranchiate acephala, three of Pallio- 
branchiate acephala, and three of hard Echinodermata, all having members 
in the Scottish portion of the regions explored, are without representatives in 
the English western and southern provinces. On the other hand, seven 
genera of Gasteropoda and eight of Lamellibranchiate acephala having 
English representatives, are altogether wanting on the western and northern 
coasts of Scotland. All our brachiopods found within the area explored are 
Scottish species; the number of monomyarious Lamellibranchiata is slightly 
in favour of Seotland over England, which, however, shows a considerable 
majority of dimyaria. The proportion of Gasteropoda in the Scottish seas 
is, however, so great, that the total number of testacea is in favour of the 
north. This is to be attributed partly to the greater variety of depths and ” 
ground, and partly to the presence in the north of isolated colonies of arctic 
forms which swell the ranks of the inhabitants of those regions to beyond 
their natural proportions. 
This table shows the total number of species of each genus of British tes- 
tacea and hard Echinodermata, compared with the number of species recorded 
in the following tables of depths; the Scottish and English regions of the 
areas to which this Report is devoted, having the number of their species 
dredged in separate columns. In order to facilitate the comparison, and to 
show cause for the differences between the latter or district columns and the 
first or general enumeration, columns showing the number of species normally 
living in the Littoral and Laminarian zones, of obscure forms said to live within 
the area explored, and of British species found only beyond the limits of 
these areas, are inserted between. I have added for general comparison a 
column showing the number of species identical with existing British forms, 
of which we find fossil remains in the later British tertiaries, taking my data 
from the valuable monographs by Mr. Searles Wood. In two other columns, 
I have inserted in the one the total number of Scandinavian species of each — 
genus in the British list, irrespective of identity, founding the list on Léven’s — 
researches; and in the other, the total number in like manner of Mediterra- © 
nean species, founding the list on the works of Phillippi, on my A2gean lists, — 
and on the dredging papers of Mr. MacAndrew. These two columns, when — 
compared with the others, will afford not a few indications of the respective 
influences of the northern and southern elements in the British marine fauna. 
The numbers of the Scandinavian Echinodermata are taken from the excel- 
lent memoir by Duben and Koren. 
