REPORT ON THE OSTE.ACODA. 53 



The two valves figured iu PI. VII. are the only examples of this si^ecies. lu the same 

 dredging, from a depth of 2050 fathoms (Station 246) were also found some specimens of 

 the next described species Bairdia minima, and it is not unlikely that one species 

 may prove to be only a fuUy-developed stage of the other. This, however, cannot 

 be decided -ndthout comparison with a larger series of specimens iu various stages of 

 growth. 



[PL VII. fig. 4, a-c. a Left valve seen laterally, h right valve seen laterally, c the 

 same seen from above. Magnified 30 diameters.] 



8. Bairdia minima, n. sp. (PI. VII. fig. 6, a-g). 



Shell, seen laterally, oblong, subovate or subtriangular, somewhat gibbous, greatest 

 height situated near the middle, and equal to nearly two-thii-ds of the length ; extremities 

 rounded, anterior broad, posterior somewhat angular and narrower ; dorsal margin strongly 

 arched and sHghtly angular or gibbous at its highest point, ventral nearly straight ; seen 

 from above, the outline is broadly and regularly ovate, widest in the middle, and tapering 

 evenly to the extremities which are pointed ; the width and height of the shell are equal ; 

 end view very broadly ovate or subcircular. [The specimen sho-mi in figures e-g difi"ers 

 only in being somewhat more compressed laterally, and may, perhaps, belong to a male, 

 figures a~d representing probably the female.] Shell perfectly smooth. Length, lr35th of 

 an inch ("75 mm.). 



Habitat. — Port Jackson, Australia, 6 fathoms, and from a depth of 2050 fathoms, 

 lat. 36° 10' N., long. 178° 0' E. Station 246. 



The characters of this species are not very well marked, and it may fairly be doubted 

 whether it be not only a young stage of some larger animal, perhaps of Bairdia 

 ahyssicola. 



[PI. VII. fig. 6, a-g. a-d specimens from Station 246. a Carapace seen from left 

 side, h from above, c from below, d from front, e-g specimens from Port Jackson ; e 

 seen from left side, /from below, g from front. All magnified 50 diameters.] 



9. Bairdia ovata (?), Bosquet (PL VII. fig. 3, a-d). 



Bairdia ovata, Bosquet, Crustaces fossiles duLimbourg, 1853, p. 63, pi. v. fig. 6, a-d. 

 Bairdia ovata, Brady, Trans. Zool. Soc. Lond., 1865, vol. v. p. 364, pi. Ivii. fig 7, a~c. 



Valves ovate, broadly and evenly rounded in front, more or less produced at the 

 infero-posteal angle. The left valve is almost perfectly egg-shaped, very broad in front, 

 the margins sweeping in one continuous curve, with a very bold dorsal, and a slight 

 ventral arch to the posterior angle, which is subacute. The right valve is, as usual, 

 narrower, distinctly beaked behind, and has the dorsal and ventral margins slightly 

 sinuous ; outline as seen from above, regularly ovate. SheU-surface qniic smooth. 

 Length, l-22d of an inch (I'l mm.). 



