DREDGING ON THE COASTS OF SHETLAND. 75 
and Mr. Norman. I could not resist the temptation of repeating my visit, last 
year, to the “ultima Thule” (if the ancients knew Shetland and called it by 
that name) ; and I was much pleased to have Professor Allman as my colleague, 
This-time we stayed at Balta. The vessel I hired, although neat to the eye, 
turned out to be a poor and unseaworthy craft, and consequently was not of 
much use. We were greatly disappointed; and our dredging was cut short 
by the rudder-post being broken in a heavy sea. I succeeded, nevertheless, 
im procuring a live specimen of Limopsis aurita (Brocchi), only known before 
as a miocene fossil and from the Coralline Crag; and Mr. Waller detected in 
some of the dredged sand, which I sent to him for examination, two fresh 
valves of Lima Sarsii (Lovén), a new species of Rissoa (to which he proposes 
to give my name), and Cleodora infundibulum (8. Wood), the latter also a 
Coralline Crag species, and hitherto unnoticed as recent. This year were 
obtained two more species of Mollusca new to the British fauna, viz. 
Arca obliqua (Philippi) and Scaphander librarius (Loven), besides four 
perfect specimens of Limopsis aurita (three of them living), three speci- 
mens of Lissoa Jeffreysi, the same number of Cithara haliaéti (one living), 
and a few very rare species, such as Spirialis Macandrei and Avinus Crouls. 
nensis, Two species (Aclis unica and Odostomia cylindrica), which had 
been considered southern forms, occurred for the first time in these northern 
latitudes, I had likewise an opportunity of confirming and extending some 
observations which I had made on former occasions as to the nature of the 
sea-bottom and bathymetrical conditions, as well as with respect to the 
bearing of these dredging-operations on certain geological phenomena. 
The detailed result of all the explorations during the last few years in 
the Shetland seas, so far as they relate to the Mollusca, will be stated at 
the end of this Report. The first Table contains a list of species which 
I have added from this source to the British fauna since the publication of 
Forbes and Hanley’s work. They are twenty-two in number. The second 
gives only a single species, which is as yet unknown elsewhere, either as recent 
or fossil, The third comprises the species (seven in number) which areunknown 
elsewhere, except in a fossil state; and the fourth such as are confined to this 
part of the British seas, being twenty-three innumber. All these last-mentioned 
species are Scandinavian—a result which might have been expected from 
the geographical situation of the dredging-ground. The distance between 
the Whalsey or Out-Skerries and the opposite coasts of Norway is scarcely 
150 miles; and this is reduced by from 20 to 50 miles where the dredgings 
were mostly carried on. 
Besides the Mollusca, some of the rarest and finest Echinoderms (e.g. 
Astrophyton Linkii, Echinarachnus placenta, and Cidaris papillosa) are only 
to be found as British in this part of our seas. Mr. Spence Bate and Mr. 
Norman have described from this source several new Crustacea, Mr. Alder 
some Nudibranchs and Zoophytes, and Professor Busk species of Polyzoa 
which had been previously considered as belonging only to the Coralline 
Crag; and Mr. Brady has noticed a great many forms or species of Forami- 
nifera heretofore said to be peculiar to the chalk and tertiary strata. 
Beyond twenty miles seaward of Unst the tides are scarcely, if at all, felt ; 
and the dredgings afforded no evidence of any marine current. In calm 
weather, the rope when hauled up was perpendicular, or (as sailors call it) 
* straight up and down.” The depth was about 85 fathoms, and it varied 
but little for several miles further out to sea or in a parallel line. Here and 
for many square leagues north, east, and west there seems to be a still or 
quiescent region at the bottom of the ocean, unaffected by the storms which 
