OSTRACODA COLLECTED IN THE SOUTH SEA ISLANDS. 495 



Anterior extremity narrow, scarcely rounded, bearing three or more small blunt, forward- 

 pointing spines ; posterior obliquely truncated, narrow, lying altogether below the middle 

 line, the obliquity looking downwards, divided into about six strong, sharp teeth ; dorsal 

 margin straight in the middle, sloping abruptly and almost in a right line at each 

 extremity ; ventral margin straight. Seen from above the outline is very irregular, 

 oblong-ovate, twice- as long as broad, widest in the middle, extremities wide, truncated, 

 and spinous. Shell-surface marked everywhere with rather large, irregular, subangular 

 impressed puncta ; abruptly depressed within the anterior margin and over the posterior 

 extremity. Length "56 mm. 



Habitat. — One perfect specimen of this curious species was found in a gathering 

 from pools on the inner reef at Apia, Upolu ; another single valve in shore-sand from 

 Porcheron's Beach, Noumea. 



The uneven outline of the shell, as seen dorsally, seems to indicate a distortion or 

 malformation; but, apart from this, the characters are so peculiar that there can be no 

 doubt as to its specific distinctness. 



Bairdia nodulifera, n. sp. (PL I. figs. 13-16). 



Shell, seen from the side, subreniform, highest in the middle, height equal to more 

 than half the length. Anterior extremity obliquely rounded and minutely serrated below 

 the middle, posterior produced below the middle into an obtusely angular beak, above 

 which it slopes forwards with a distinct sinuation, the curve encroached upon by two slight 

 rounded projections and minutely serrated below the middle ; dorsal margin boldly arched, 

 ventral slightly sinuated in the middle. Seen from above, compressed, ovate, widest in the 

 middle, more than twice as long as broad; lateral margins evenly and moderately convex, 

 twice or thrice emarginate near the extremities ; extremities obtuse, subtruncate. Surface 

 of the valves smooth, marked with closely set, small, circular impressions ; within the 

 anterior border are three or four large, but not very prominent, rounded tubercles, and 

 the posterior margins have a somewhat similar armature. These tubercles are not at all 

 conspicuous when seen laterally, but the marginal irregularities produced by them, when 

 seen dorsally or ventrally, are very characteristic. Right valve smaller and more angular 

 than the left. Length - 8 mm. 



Habitat. — Levuka, between tide-marks. One specimen only seen. 



Bairdia tuberculata, G. S. Brady. 



Bairdia tuberculata, Brady, " Ostracoda of Challenger Expedition," p. 60, pi. x. fig. 3 a-d. 

 Habitat. — Port of Noumea, 3-6 fathoms. 



Bairdia expansa, G. S. Brady. 



Bairdia expansa, Brady, " Ostracoda of Challenger Expedition," p. 58, pi. xi. fig. 2 a-e. 



Habitat. — Lufi-Lufi, reef and shore-pools ; Apia, Upolu, reef and shore-pools 

 Noumea, between He Pore-Epic and shore, 2-6 fathoms. 



