ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 



Summary. 



247 



Obs. The Shetland Nudibranchs and Cephalopods have not been sufficiently 

 investigated. Loven's ' Index ' and a further list of Swedish Nudibranchs 

 which he lately sent me contain 60 species of that order, out of which 25 

 ,only have been identified as Zetlandic. He also gives 9 species of Cephalo- 

 pods, of which 5 only are Zetlandic. The southern distribution of our Nu- 

 dibranchs is very little known. For the preparation of the present list of 

 Nudibranchs I am in a great measure indebted to the late Mr. Alder and to 

 Mr. Norman. Forty-eight species of mollusca (marked f) have been discovered 

 in the Shetland seas since tho publication of Forbes & Hanley's ' History of 

 British Mollusca and their Shells. 7 



Shetland Final Dredging Report. Part II. On the Crustacea, Tuni- 

 cata, Polyzoa, Echinodermata, Actinozoa, Hydrozoa, and Porifera. 

 By the Rev. ALFRED MERLE NORMAN, M.A. 



THE especial object with which the Shetland dredging was recently under- 

 taken, under the auspices of the British Association, was the examination of 

 the fauna of the deep water which surrounds that most northern group of 

 our islands. The abyss of the sea there approaches near to land at a depth 

 rapidly descending to eighty or one hundred, and subsequently reaching 

 many hundred fathoms. The sea-bottom at such a depth would never have 

 been laid bare during those two great upheavals of the earth's surface which 

 appear to have been the last great geological oscillations over the area of the 

 north-west of Europe. At a time when all the channels and sea which now 

 separate our islands from each other, and from the rest of Europe, were raised 

 high and dry above the level of the ocean, and the whole formed part of one 

 great continent, the sea, if the calculations as to the extent of that elevation are 

 anything like the truth, must still have broken on the rocky shores of the 



