440 MR. G. S. BRADY'S MONOGRAPH OF 



Sars's description. The three-jointed character of the urticating seta (flagellum) is not 

 noted by Sars, and I cannot say whether it holds good throughout the genus ; it is, how- 

 ever, very distinct in all the specimens which I have examined of C. nigrescens. The 

 genus is distinctly characterized, externally, by the peculiarly beaked hinder ex- 

 tremity. 



1. Cytheuura nigrescens (Baird). (Plate XXXII. figs. 50-55, and Plate XXXIX. 



fig. 7.) 



Cythere nigrescens, Baird, Brit. Entom. p. 171, tab. xxi. figs. 4, 4 a. 

 Cytherura nigrescens, G. O. Sars, loc. cit. p. 71. 



British tj'pe. Distribution : Recent — Norway, Great Britain, Ireland. Fossil — Glacial, Norway, Scot- 

 land, Ireland. 



Carapace of the female, as seen from the side, subovate, greatest height in the middle 

 and equal to half the length ; rounded in front, behind produced about the middle into a 

 short obtuse beak ; superior margin well arched, inferior slightly incurved. Outline, as 

 seen from above, compressed ovate ; greatest breadth behind the middle, and equal to 

 less than half the length ; extremities acuminate. The male similar, but rather more 

 elongated. Valves smooth or sparingly punctate, and bearing a few small scattered 

 hairs, marked with long, hair-like, radiating lines on the anterior and posterior margins ; 

 pellucid at the extremities ; central areola convex in front, deeply concave on its hinder 

 margin, often mottled with deep black. Last joint of the upper antennse very short ; 

 the penultimate and antepenultimate nearly equal and much longer than the preceding. 

 Terminal claws of the feet robust and much curved. Second joint of the last pair of feet 

 about as long as the united lengths of the two following. " Apical portion of the male 

 copulative organs small, subtriangular, with acute angles." 



Length ^ in. s->» - • 



Hab. Littoral, and in depths up to 10 fathoms. In rock-pools at Sunderland and Arranmore; dredged 

 amongst mud in Roundstone and Birterbuy Bays ; in oyster-ooze from Stranraer, and in shell-sand 

 from South Wales (G. S. B.) ; in rock-pools, Herm, Guernsey, and Arran ; and in shell-sand from 

 Berwick and Isle of Skye (Rev. A. M. Norman) ; Lerwick, Shetland, Isle of Man, and Oban (ilfr. D. 

 Robertson) ; Minch {Mr. J. G. Jeffreys) ; Loch Erribol [Mr. D. 0. Drewett) . 



When living between tide-marks this species is always more or less marked with 

 ])lack ; sometimes the central areola forms one deep-jet-black patch, but more frequently 

 is flecked with irregular black stria? or spots. Specimens dredged from beyond low- water 

 mark, though showing the outline of the areola, are altogether destitute of colour. The 

 form figured (54, 55) from the Minch was dredged in a depth of about 50 fathoms, and 

 may possibly be distinct ; but it approaches C. nigrescens so closely that, for the present, 

 I prefer to regard it as a variety only of that species. 



2. Cytherura angtjlata, n. sp. (Plate XXXII. figs. 22-25.) 



Carapace, seen laterally, subquadrangular, greatest height in the middle, and equal to 

 about half the length, evenly rounded in front, produced behind above the middle into a 

 rather long, obliquely truncate beak ; superior margin evenly arched, inferior slightly 



