RECENT BRITISH OSTRACODA. 



451 



ventral margin sinuated in front, very convex behind. The valves are bordered by a 

 broad, flattened flange, which bulges conspicuously near the middle of the ventral margin, 

 and is lost on the dorsum ; the flange is marked by numerous closely set radiating hair- 

 like lines. Outline, as seen from above, elongate fusiform, more than thrice as long as 

 broad, narrowed in front, slenderly acuminate behind, the right valve overlapping the 

 left. Shell of the male scarcely different from that of the female. Lucid spots five, 

 forming an oval patch a little below and in front of the centre of the valve ; spots parallel, 

 the three central ones linear-oblong, the terminal ones oval or lenticular. Shell perfectly 

 smooth, thin and structureless, pellucid, slightly olivaceous, with arborescent markings 

 of a deeper tint. Hinge-margins straight, quite simple. Last pair of feet in the male 

 subprehensile, last three joints very robust, terminal claw very strong. Distal portion of 

 the male copulative organs large, irregularly triangular, subtruncate at the apex ; anterior 

 margin straight, posterior deeply sinuated. No eyes. 

 Length of female 2^ in. 



Hab. Off Holy Island, Northumberland, in 45 fathoms ; off Scarborough, and in dredgings from Shetland 

 (G. S. B.) ; Dogger bank {Rev. A. M. Norman) ; Aberdeenshire coast [Mr. Dawson) ; off Cumbrae, 

 Bute, and Ormeshead, and at low water-mark in the Isle of Man [Mr. D. Robertson) ; the Minch 

 [Mr. J. G. Jeffreys). 



This species was first described by the Rev. A. M. Norman, from specimens taken in 

 deep water a hundred miles off the coast of Northumberland, and shortly afterwards by 

 G. O. Sars from Norwegian specimens. Though widely distributed, it seems to be, in 

 point of numbers, rather a scarce species, the only British gatherings in which it has 

 occurred at all abundantly being those from the Aberdeenshire coast and from off 

 Scarborough. It occurs in the Arctic seas, and also in a fossil state in the Scotch glacial 

 clays. 



2. Btthocythere constricta, G. O. Sars. (Plate XXXV. figs. 47-52.) 

 Bythocythere constricta, G. O. Sars, loc. cit. p. 85. 



Carapace tumid, expanded into an obtusely angular lateral protuberance behind, 

 slightly constricted in the middle ; ventral surface nearly flat. Shell of the female, as 

 seen from the side, subrliomboidal, rather higher behind than in front ; greatest 

 height equal to rather more than half the length ; obliquely rounded in front, produced 

 behind above the middle into a short, obtusely rounded (sometimes bluntly toothed) 

 process. Dorsal margin nearly straight ; ventral sinuated in front, convex behind. Out- 

 line, as seen from above, ovate, widest behind the middle, strongly acuminate behind ; 

 greatest width equal to considerably more than half the length. Shell of the male, 

 as seen from the side, much more elongated, highest behind ; greatest height equal to 

 less than half the length; posterior extremity obliquely truncate, and less produced 

 above. Surface of the shell marked with rather distant, round punctations, wiiich are 

 connected with each other by more or less distinct, depressed lines, thus producing a 

 faint reticulation ; ventral surface longitudinally striated, and bearing numerous floccu- 

 lent white papillse; infero-posteal angle armed (frequently) with 3-5 minute teeth. 

 " Penultimate joint of the upper antennae longer than the preceding. Second joint of 



3 p 2 



