IMPERFECTLY-KNOWN SPECIES OE OSTRACODA. 433 



Frontal tentacle (fig. 27) three-jointed, the median joint very short and constricted at 

 the base, distal joint conical, with a much-attenuated apex ; secondary branch of the 

 antenna (fig. 26) three-jointed, cylindrical, ending in a long seta, the two basal joints 

 bearing a few marginal hairs; teeth of the bifid extremity of the vermiform limb 

 (fig. 28) corrugated, their apices formed by a small spine, which is overhung by a 

 knobbed columnar process: abdomen fringed distally with closely-set hairs; post- 

 abdominal laminee (fig. 29) bearing three very stout, blunt, and strongly curved distal 

 ungues, which bear two marginal rows of closely-set lancet-shaped spinules (fig. 30) ; 

 in front of the ungues is a series of about nine long ringed and pinnated setae. ° Male 

 unknown. 



Hal. Eock-pools, Stewart Island. 



This fine species closely resembles in external aspect G. orbicularis, of which a 

 single specimen from Valparaiso was described by me (loc. cit.), but C. ovulum is much 

 larger, and differs in many points as regards the soft parts. 



Ctclasterope tenera, sp. n. (Plate XLIV. figs. 27-29.) 



Female. Shell, seen from the side (fig. 27), almost circular, slightly narrower towards 

 the front, length about one-seventh greater than the height, very thin, membranous, 

 and slightly wrinkled ; anterior and inferior margins beset with distant, rigid hairs. 

 Secondary antennal branch (fig. 28) simple, three-jointed, with a long apical seta; 

 falcate process of the mandible bearing numerous marginal spines and teeth;' 

 the post-abdominal claws are three in number (fig. 29), very unequal in length, and 

 armed with closely-set short marginal spinules. Length 1-5 mm. 



Hob. Lyttelton Harbour, 1-5 fathoms. One specimen only. 



Cyclasterope zealandica (Baird). (Plate XT, ITT figs. 15-23.) 

 Cypridina zealandica Baird (i), p. 257, pi. xvii. fios. 11-13. 



Shell of the female (figs. 15, 16), seen from the side, very broadly ovate, length 

 about one-fourth greater than the height, the outline forming a perfect oval except at 

 the antennal notch, which is small and shallow ; seen from above, ovate, compressed, 

 greatest width in the middle, and equal to half the length ; extremities rather wide and 

 evenly rounded, slightly emarginate at the contact of the valves. Shell calcareous, 

 finely punctate and, towards the anterior extremity, faintly wrinkled in a transverse 

 direction (fig. 23). Length 5 mm., height 4 mm. Secondary branch of the antenna 

 (fig. 19) cylindrical, three-jointed, geniculated, the first joint bearing a tuft of marginal 

 setse near its extremity, second joint with three small marginal setae externally and a 

 long seta on its internal distal angle, last joint obliquely truncate and mucronate at 

 its apex ; ungues of the post-abdominal lamina? (fig. 21) stout, subequal, and strongly 



