166 
NAL ORE 
[ Dec. 9, 1869 
THE DEEP-SEA DREDGING EXPEDITION, 
IN H.M.S. “PORCUPINE” 
NATURAL HISTORY (continued) 
ope tais being a preliminary report, I will make only a 
few remarks as to the Mollusca obtained in the ex- 
pedition, and with respect to that part of the sea-bed 
which I investigated :— 
1. Zhe Mollusca are mostly Arctic or Northern.—This 1 
have shown in my narrative as regards the western coasts 
of Ireland, which have hitherto been supposed to belong 
zoologically to what Professor Edward Forbes called the 
““Lusitanian” province ; and the present remark applies 
not only to deep water, but to shallow water, and even the 
bays. In Prof. Wyville Thomson’s cruise to the south- 
west of Ireland occurred two species, which I was quite 
unprepared to see. These were Solarium Siculum, and 
an unmistakeable fragment of Casstdaria Tyrrhena. The 
former inhabits the Mediterranean, Madeira, Canaries, 
and the coast of Portugal ; and the latter has not been 
noticed north of Brittany. Such exceptions, as well as 
Ostrea cochlear, Murex imbricatus, and Platydia ano- 
miotdes, it is difficult to account for; but as all these 
species are said to inhabit deep water, the Equatorial 
current may have carried them northwards in an embryonic 
state ; or it is possible that they may be likewise Northern 
species, and have not yet been discovered in high latitudes. 
We are nearly ignorant of the Arctic Mollusca, owing to 
the difficulty of exploration ; and those who assume that 
the marine fauna of the circumpolar seas is poor or wants 
variety, ought to see the vast collection made by Prof. 
Torell at Spitzbergen. The greatest depth at which he 
dredged there was 280 fathoms. The soundings taken in 
1868 by the last Swedish Expedition reached 2,600 fathoms, 
when a Cuma and a fragment of an Astarte came up 
in the Bulldog machine. Soundings, however, are very 
insufficient for zoological purposes. Judging by the results 
of our own expedition this year, which have increased to 
such a wonderful extent our list of the British marine 
fauna living beyond the ordinary line of soundings, it may 
fairly be taken for granted that the Arctic marine fauna is 
much less known than ours. I have not the slightest doubt 
that by another expedition to Spitzbergen, provided with 
improved machinery, and under the charge of the Professor 
at Lund or some other able zoologist, the species obtained 
would be double the present number. It is evident that 
the majority, if not the whole of our submarine (as contra- 
distinguished from littoral or phytophagous) Mollusca 
originated in the North, whence they have in the course of 
time been transported southwards by the great Arctic 
current. Many of them appear to have found their way 
into the Mediterranean, or to have left their remains in 
the tertiary and quaternary formations of the south of 
Italy ; some have even migrated into the Gulf of Mexico, 
as I will presently mention. 
I cannot see much (if any) difference between the 
Mollusca from the warm and cold areas of Dr. Carpenter. 
The number of species from the cold area, which also 
occurred in the warm area, is forty-four. Other species 
from the cold area, and not from the warm area, are eleven. 
Of these last, five are undescribed, and one is apparently 
sub-fossil and may be a relic of the glacial epoch; so 
that there remain five only which are Arctic and North- 
American, but which were not found in the warm area. 
2. Additions to the British Mollusca.—Although I am 
aware that the discovery of what are called “new” 
species does not rank high asa scientific fact, it is still 
interesting to all zoologists as well as collectors; and it 
must not be forgotten that the important subject of 
zo6-geographical distribution depends in a great measure 
on such discoveries, and especially on the relation of any 
local fauna to other faunse. The number of species new 
to our seas and procured in this expedition is no less than 
117, Of these, fifty-six are new to science, and eight 
were supposed to be extinct as tertiary fossils. Sixteen 
genera are new to the British seas, including five which 
are undescribed. Some of the species and genera, how- 
ever, are represented by single specimens, and a few by 
fragments. These whet one’s appetite instead of satisfy- 
ing it. The total number of species of our marine Mol-. 
lusca, inclusive of littoral species but exclusive of the 
Nudibranchs (none of which latter were met with except 
in the bays), is 451, according to the latest work on the 
subject, ‘ British Conchology :’ so that more than one- 
fourth has been added in the course of a few months. 
All that I could do by continual dredgings in compara- 
tively shallow water during the last sixteen years was to 
add about eighty species to the number described by 
Forbes and Hanley. I regard the present (although a 
large) addition as merely an earnest of future acquisitions. 
Almost every square mile of the sea-bed yields different 
species, some being apparently local or restricted in their 
distribution. In fact the treasury of the deep is inex- 
haustible. 
3. Relation to North-American Mollusca —The late 
Dr. Gould, in his ‘ Report on the Invertebrata of Massa- 
chusetts’ (1841), gave 176 species of marine Mollusca as 
inhabiting that coast. Mr. Mighels, Prof. Stimpson, and 
others have since described a few more species, making the 
total number about 200, I attifie; leas 6ohaieddnts 
of these as British, a dozen being from the present expe- 
dition. The size of North-American specimens is, so 
far as I have observed, smaller than that of our speci- 
mens of the same species, perhaps showing that their 
common origin was in the Arctic seas of Europe and not 
of America. 
4. Relation to Mediterranean Mollusca.—In my last 
Report on Shetland dredgings, published a short time ago 
by the British Association, I discussed this subject so 
fully that it is needless to go further into it, except by 
calling the attention of the Society and all scientific men, 
particularly geologists, to the importance of ascertaining 
what has caused or is still causing the remarkable con- 
cordance which is observable between the marine Mollusca 
in the deeper parts of the North-Atlantic and Medi- 
terranean. I cannot help now thinking that this con- 
cordance may be explained by the existence of an 
undercurrent into the Mediterranean through the Straits 
of Gibraltar, being probabiy a branch of the great Arctic 
current. Dredging researches ought to be carried on in 
the lower part of the Bay of Biscay, and off the coasts 
of Portugal and Spain into the Straits for the purpose of 
determining this vexed and highly interesting question. 
Dr. Carpenter’s last cruise to the west of Shetland, at a 
depth of 290 fathoms added a remarkable species to our 
Mollusca in Platydia anomioides, a rare Mediterranean 
Brachiopod. The specimen is twice the size of those 
from the Mediterranean. Octopus Cocco of Verany is 
another remarkable discovery, and was dredged in 345 
and 632 fathoms between latitudes 60° and 62° N. It 
was only known as Mediterranean, where it is stated by 
Verany to inhabit a depth of 100 métres or nearly 55 
fathoms. The dimensions of our largest specimen of 
this Caphalopod considerably exceed those given by 
Verany. I may here mention that my friend Captain 
Spratt, who co-operated with Prof. Edward Forbes in his 
Atgean exploration, has most obligingly placed at my 
disposal a very small quantity of material which he 
dredged in 1846, forty miles east of Malta, at a carefully 
ascertained depth of 310 fathoms. It contains among 
others the following remarkable species of Mollusca, all 
of which were found in the Porcupine expedition, and may 
be considered northern forms :—Leda pellucida (Phil.), 
Leda acuminata (Jeffr. M.S.), Dentalium agile (Sars), 
Flela tenella (Jefir.), Eulima stenostoma (Jeftr.), Trophon 
Barvicensis (Johnst.), Pleurotoma carinata (Biv.), and 
Philine gquadrata (S. Wood). This shows how imperfect 
is our knowledge of the Mediterranean fauna, 
