REPORT ON THE OSTRACODA. 91 



51. Cijihere ohtuscdata, u. sp. (PL XII. fig. I, a-c). 



Valves, seen from the side, subquadrangular, higiicst over the anterior hinge ; anterior 

 extremity obliquely rounded, posterior produced below the middle into a broad, irregularly 

 dentated, beak-like process ; dorsal margin sloping gently from the rather gibbous anterior 

 extremity, ventral straight ; height equal to more than half the length ; seen from above, 

 the lateral margins form a median alfeform projection which ends abruptly behind, and 

 tapers gently away towards the front. The surface of the shell is marked throughout 

 with closely-set and not very large subangular excavations, l3ut has no trace of 

 ribbed ornament. Length, l-43d of an inch ('57 mm.). 



Only detached valves of this species were found in the following dredgings : — Oif East 

 Moncceur Island, Bass Straits, 38 to 40 fathoms, and in 16 to 25 fathoms off Admii-alty 

 Islands. 



[PI. XII. fig. 1, a-c. a Right valve seen from side, h from above, c from front. 

 Magnified 60 diameters.] 



52. Cythere lactea, G. S. Brady (PI. XXII. fig. 1, a-d). 



Cythere ladea, Brady, Tran.s. Zool. Soc. (1865), vol. v. p. 377, pi. Ix. fig. 3, a-c. 



Carapace, seen from the side, oblong, c[uadrangular, higher in front than behind, 

 greatest ■ height equal to nearly two-thirds of the length ; anterior extremity broadly 

 rounded ; posterior truncated, slightly toothed below and excavated above the middle ; 

 dorsal margin sinuated behind the anterior hinge, thence sloping gently to the posterior 

 extremity ; ventral margin straight ; seen from above, the outline is irregularly hexagonal, 

 oblong, with subparallel sides, which are deeply indented in the middle, and converge 

 aljruptly and sinuously towards the obtuse, truncated extremities ; the end view is 

 subtriangular, with irregularly notched sides, and broad, rather convex, base. The 

 surface of the shell is covered with closely-set angular excavations ; wdthin the 

 ventral and posterior margins runs an elevated ridge, and on the front of each valve 

 is a rounded tubercvilar prominence (not shown in the plate). Length, l-50th of an inch 

 (•5 mm.). 



From a sounding made in a depth of 420 fathoms (mid-Pacific, about lat. 40° S.). 



These specimens appear to be referable to a Cythere which was described by 

 me from one shell only, under the name lactea, in the Transactions of the Zoological 

 Society {loc. cit.). The tjrpe specimen is more sharply sculptured and rather longer than, 

 those now figured and described, but considerable latitude must be allowed for difference 

 of race and habitat. As a general rule, Ostracoda dredged from great depths are more 

 blurred in their features than the same species from shallower water. 



[PI. XXII. fig. 1, a-d. a Shell seen from left side, h from above, c from below, 

 d from front. Magnified 60 diameters.] 



