Natural Hhtory of East Finmarh. S 



urosome ornamented with a wonderful series of simple, furcate, 

 or three-branched large horn- like processes, wliich are 

 arranged as follows : — As regards the dorsal surface : on 

 each side of the centre of the hinder margin of the cephalo- 

 some is a backward-directed, simple, lancet-shaded^ setose 

 process, flanked on the inner side bj two minute similar 

 processes ; each of the four following segments is furnished 

 with a similar pair of lancet-shaped processes, but devoid of 

 the more minute flanking processes. This dorsal decoration 

 is, however, inconspicuous and of little moment compared 

 with the large appendages borne on the lateral margins, 

 which are as follows : — On each side of the cephalosome there 

 is near the base of the antennule a small simple process * ; 

 this is followed bj a trifid process, then by a bifid process, 

 this again by another trifid process ; these four processes 

 increase in size from the first to the last. The first, second, 

 and third segments of the metasonie bear on their side a trifid 

 process similar to the last of those on the cephalosome. On 

 the fourth segment of the metasonie and on the first three of 

 the urosome the smaller of the three horns of the trifid process 

 disappears, and the two that remain are more entirely separated 

 from each other at their base and have acquired still greater 

 size; so that the lower and larger of them attains on these 

 segments a length which equals about three quarters of the 

 breadth of the segment from which they spring. 



The branches of the caudal furca are very long, nearly 

 equalling the length of the three preceding segments ; at 

 half their length there is a spinule on the outer margin, and 

 they terminate in a strong and greatly produced stiliform 

 seta, at the base of which are two or three minute setae. The 

 length of the furca and its attached setae is nearly if not quite 

 equal to that of the entire rest of tlie animal. 



Length 0'8 millim. 



This is a most extraordinary and beautifully constructed 

 species. Only one other genus of the Harpacticoida has yet 

 been found which surpasses Ancorabolus with respect to the 

 remarkable development of tlie body ornament : tliat species 

 is the wondeiful Fontostratiotes ahi/ssicola, G. S. Brady, of 

 the 'Challenger' Expedition, which was dredged on the bed 

 of the North Atlantic, lat. 37" 29' S., long. 27° 31' N., in 

 2200 fathoms. 



Ancurabolus mirabilis was first dredged in 1888 in the 

 Firth of Clyde, when I was a guest of Sir John Murray in 

 his steamer the ' Medusa.' It was blowing rather hard for 

 dredging, and we ran under the lee of the east side of Little 



* This first small simple process appears to be sometimes absent. 



1* 



