REPORT ON THE OSTRACODA. 143 



margin is broken also by the projecting mucronate processes of the lateral alse ; end view 

 irregularly quadrilateral, widest near the base, height equal to about two-thirds of the width 

 only ; dorsal line nearly flat, ventral deeply excavated in the middle, and ending in broad, 

 well-rounded angles ; lateral margins sinuated in the middle. The surface of the shell is 

 onamented in a manner very similar to that of Bythocy there arenacea, but the ventral area 

 is depressed, and marked with longitudinal furrows. Length, l-66th of an inch ("39 mm.). 



Found only at Balfour Bay, Kerguelen Island, in a depth of 20 to 50 fathoms 

 (Station 149). 



[PI. XXXIII. fig. 4, a-d. a Shell seen from left side, b from above, c from below, d 

 from front. Magnified 80 diameters.] 



4. Bytkocythere velifera, n. sp. (PL XXXIII. fig. 5, a-c). 



Valves, seen from the side, subrhomboidal, height equal to more than half the length, 

 anterior extremity oblique, subtruncate, only slightly rounded, j)osterior looking obHquely 

 downwards, almost straight, and endina; above in an acute anoie, dorsal maroin straip'ht, 

 slightly curved downwards at the hinder end, ventral margin formed for the most part by 

 a huge lateral ala which occupies the larger part of the inferior half of the valve, its lower 

 border being nearly straight, the anterior joining the surface of the valve with a forwards 

 curve, the posterior almost at a right angle ; seen from below the lateral alse form the 

 entire central part of the shell, the extremities constituting two broad mucronate projec- 

 tions, the margins of the lateral alte sweep forwards in a full curve from the posterior 

 angle which is sKghtly produced, while behind they converge in a sinuated line, but 

 almost at a right angle ; the width of the complete shell would seem to be greater than 

 the length, but single valves only have been seen. Surface smooth, and slightly undu- 

 lated. Length, l-48th of an inch ("52 mm.). 



A few detached valves only found in Torres' Straits, lat. 11° 35' S., long. 144^^ 3' E., 

 155 fathoms. 



[PL XXXIII. fig. 5, a-c. a Left valve seen from side, h from above, c from front. 

 Magnified 50 diameters.] 



5. Bythocythere (?) exigua, n. sp. (PL VI. fig. 7, a-d). 



Carapace, seen from the side, subovate, smaller in front than behind, highest in the 

 middle, the height being equal to more than half the length ; anterior margin narrow, and 

 imperfectly rounded, posterior broader, and more distinctly rounded ; dorsal margin 

 arched, slightly gibbous in the middle, ventral nearly straight behind the middle, then 

 rather suddenly bent upwards towards the front ; seen from above, the outline is broadly 

 oval, widest in the middle, margins fully curved, anterior extremity obtuse, scarcely 

 pointed, posterior narrow, subtruncate and emarginate in the middle, width equal to the 

 height ; end view almost cii'cular, slightly keeled in the middle of the ventral margin. 



