ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 263 



the main followed the arrangement of Bell's ' British Stalk-eyed Crustacea ; ' 

 but the law of priority in nomenclature is not sufficiently attended to in 

 that work, and it is necessary therefore, in numerous instances, to substitute 

 the earlier names under which the species was described ; and moreover so 

 greatly has the study of even these larger and better known Crustacea 

 advanced during the last few years that, of the seventy-eight species of this 

 subclass here recorded, no less than thirty-one are undescribed in the 

 work referred to. In the Amphipoda and Isopoda I have followed the 

 general arrangement of the recently published work upon ' The British Ses- 

 sile-eyed Crustacea,' by Messrs. Bate and Westwood. In the Ostracoda, two 

 admirable guides exist in Herr G. r O. Sars's ' Oversigt af Norges marine 

 Ostracoder, 1865,' and Mr. G. S. Brady's " Monograph of the recent British 

 Ostracoda" (Trans. Linn. Soc. vol. xxvi. 1868). In the Copepoda, I have 

 derived great assistance from Dr. Claus's ' Die frei-lebenden Copepoden,' and 

 from the smaller memoirs by the same author. Descriptions of most of 

 the remaining species in the following catalogue must be sought in the 

 various papers, monographs, and works which will be found referred to in 

 the text. 



Order BRACHYURA. 



Stenorhynchus rostratus (Linn.) (S.pfalanyiwn, Penn.). 5-70 fathoms, hard 

 ground, frequent. 



longirostris (Fabr.) ($. tenuirostris, Leach). A few specimens off Balta &c. 



Inachus Dorsettensis (Penn.). Yery rare. One specimen in 1864, and a few 

 more in 1867. 



dorhynclms, Leach. Bressay Sound, off Balta, <fec. 



leptochirus, Leach. Not rare in deep water. 



Hyas araneus (Linn.), Large in laminarian zone. 



coarctatus, Leach. The most abundant of the higher Crustacea in the 



Shetland seas. 



Eurynom.e aspera (Pennant). Rare. 



Xantho rivulosus (Risso). One young specimen dredged (1867) near the Island 

 of Balta. Small examples have been taken in Sweden by Loven and 

 Goes. 



Cancer pagurus, Linn. 



Carcinus mcenas (Linn.). Remarkably large. 



Portunus depurator (Linn.). Yery rare, only two specimens. 



liolsatus, Fabr. Frequent. 



pusillus, Leach. Frequent. 



tuberculatus, Roux, Crust, de la Mediterranee, pi. xxxii. figs. 1-5, = 



Portunus pustuhitus, Norman, Brit. Assoc. Rept. 1861 (1862), p. 151. 

 This fine addition to our fauna was first procured by me in 1861, and 

 has been taken every year since. It is the most abundant of the genus 

 in the Shetland seas, living in 80-120 fathoms. The fact of this fine 

 Mediterranean species occurring in the deep Shetland seas, in company 

 with many other southern forms, which are not known in intermediate 

 localities between the Mediterranean and the most northern portion of 

 the seas, is highly interesting. Portunus tuberculatus is distinguished 

 by its tubercular, pustulose carapace, by the acuteness of the latero- 

 anterior teeth, and the great size of the posterior tooth, which is double 

 the length of the preceding ones, and by the last legs having the swim- 

 ming-blade furnished with a raised median line. 



