666 Beady and Norman — Monograph of the Marine and Freshwater Ostracoda 



extremity imperfect, but showing a very peculiar unguis, which is slightly curved, 

 ciliated, and bearing a small secondary spine on the convex margin. 



A few specimens were dredged by the "Talisman" off the West Coast of 

 Morocco in 1882 and 1883, in depths ranging from 836 mfetres; and another 

 specimen " off the Coasts of the Soudan," in 2333 metres (Marquis de Folin). 



2. Streptoleberis rectirostris, n. sp. 



(Plate Lix., figs. 11-13.) 



Shell in general form sub-quadrate, but less high behind than in front • 

 gi'eatest height anterior, while the greatest width is posterior ; ventral margin 

 strongly convex in front, and sweeping evenly to the bottom of the antennal 

 sinus, behind only very slightly arcuate, and sloping gently upwards to the 

 extremity of the posterior projection, which is slightly below the middle ; dorsal 

 margin passing from the extremity of the rostrate process, without arcuation, 

 obliquely upwards and backwards to the point of greatest height, thence along 

 the central dorsal portion it is straight, or even slightly concave, behind this it 

 slopes suddenly downwards to the point where it meets the ventral margin, and 

 forms with it the posterior sub-central blunt projection. The rostrate process is 

 directed straight forwards, and is sub-triangular, of moderate length, and rounded 

 at the extremity. It forms with the arcuate backward-sloping ventral margin 

 a widely gaping, shallow antennal sinus. Valves very finely punctate, and 

 furnished with a longitudinal acute ridge slightly below the centre, running 

 backwards till it nearly reaches the posterior extremity ; in front a branch runs 

 downwards from this ridge to near the ventral margin, and then bending back- 

 wards it encircles that margin ; opposite the oi'igin of this ridge another runs 

 obliquely ujDwards and backwards, and ultimately jDassing downwards loops with 

 the first described ridge, and with it encloses a sub-triangular space, which is 

 the most gibbous portion of the shell ; in front of the ridges described, and 

 just behind the sinus, a much narrower ridge traverses the valves vertically ; 

 at the hinder extremity, beyond the looping-ridge described above, the valves 

 are suddenly and greatly depressed. The greatest height is three-fifths of the 

 length, and slightly greater than the greatest width. Seen from above the form 

 is slightly cuneiform, excessively wide behind, where it is suddenly trmrcate 

 (the posterior extremity of the shell only slightly projecting in the centre of 

 the truncate extremity) ; the sides thence converge without convexity, forwards, 

 until slightly before the rostrum they more suddenly converge, and beyond this 

 the rostrate process is seen protruded, with its length and breadth sub-equal. 

 Length, 1'6 mm. ; height, "9 mm. 



