OSTRACODA COLLECTED IN THE SOUTH SEA ISLANDS. 493 



serratures are very variable, but the anterior extremity is often minutely serrated, and 

 the posterior portion of the ventral margin generally has a series of somewhat larger 

 teeth. Seen dorsally, the outline presents considerable variation, being sometimes wide 

 in the middle and very boldly and evenly curved ; in other cases the greatest width is in 

 front of the middle, and the posterior portion is tapered. I have not been able to make 

 out the meaning of these differences. In such specimens as I have dissected the 

 rounded, tumid shells were, contrary to my anticipation, males. The more tapered 

 form, with anterior tumidity, may perhaps be the female, but of this I am not sure. 

 The figures given in the "Challenger" Report represent tolerably well the centrally 

 tumid form only. 



Bairdia tenera, G. S. Brady (PI. I. figs. 11, 12). 



Bairdia tenera, Brady, " Entomostraca collected in Ceylon," Jour, of Linn. Soe. (Zoology), 

 vol. xix. p. 304, pi. xxxix. figs. 13-15. 



Shell, seen from the side, subreniform, highest in the middle, height somewhat less 

 than two-thirds of the length; anterior extremity wide, obscurely angulated at its 

 junction with the dorsal margin, and obliquely rounded below ; posterior extremity some- 

 what produced in the middle, but scarcely beaked, obliquely rounded off below ; dorsal 

 margin nearly flat for the greater part of its course, and sloping abruptly towards both 

 extremities ; ventral distinctly sinuated in the middle, and minutely dentated towards 

 the posterior extremity. Seen from above, compressed, ovate, widest in the middle, not 

 quite thrice as long as broad ; extremities obtusely pointed. Surface of the shell smooth, 

 beset with numerous very fine but rigid short hairs, and marked with closely-set im- 

 pressed puncta. Length '85 mm. 



Habitat. — Pools on reef, Lufi-Lufi ; and Apia, Upolu.* 



Bairdia Crosskeiana, G. S. Brady. 



Bairdia Crosskeiana, Brady, " Ostracoda of Challenger Expedition," p. 58, pi. ix. fig. 3 a-e. 

 Habitat. — Mud-flats, Suva ; pools on reef, Lufi-Lufi ; and Apia, Upolu. 



Bairdia foveolata, G. S. Brady. 



Bairdia foveolata, Brady, "Ostracoda of Challenger Expedition," p. 55, pi. viii. fig. 1 a-f, and 

 fig. 2 a-f. 



Habitat. — Noumea, shore-sand, and dredged in 2-6 fathoms ; mud-flats, Suva ; Sava- 

 Sava Bay, 4 fathoms ; Lufi-Lufi, Samoa, pools on reef ; Apia, Upolu, tidal pools ; Mango 

 Island, Fiji, fringing reef ; Vuna Point, Taviuni, between tide-marks. 



This species is largely represented in many localities. Like B. amygdaloides, it is in 

 the living condition beautifully marked with blotches of a chocolate-brown colour, and is 



* The single specimen from which the species was first described was unfortunately lost by the draughtsman who 

 made the drawings, but these Samoan shells seem to agree almost exactly with the description, and I have but little 

 hesitation in referring them to the same species. 



