40 THE VOYAGE OF H.M.S. CHALLENGEE. 



1. Argillcecia ehurnea, n. sp. (PI. IV. figs. 1-15). 



Shell oblong, compressed, subreniform, height less than half the length ; seen from 

 the side the anterior extremity is obliquely rounded ; posterior produced, and subacute 

 at the ventral angle ; dorsal margin boldly arched, highest in the middle, sloping, with 

 a gentle curve forwards, and steeply backwards, as far as the ventral angle ; ventral 

 margin rather deeply sinuated in the middle ; seen from above, compressed ovate, widest 

 near the middle, acuminate in front, rounded behind, width equal to the height ; end 

 view nearly circular. Surface of the shell perfectly smooth. Length, l-32d of an inch 

 {■77 mm.). 



Argillcecia ehurnea, occurred plentifully in two dredgings from Kerguelen Island, — 

 Balfour Bay, 20 to 50 fathoms, and off Christmas Harbour, 120 fathoms; also in lat. 

 35° 39' S., long. 50° 47' W., 1900 fathoms (Station 323). 



[PI. IV. figs. 1-15. Fig. 1, shell of male seen from left side; fig. 2, from above; 

 fig. 3, from below ; fig. 4, from front ; fig. 5, anterior antenna ; fig. 6, posterior 

 antenna; fig. 7, mandible and palp; fig. 8, first maxilla; fig. 9, second maxilla (male); 

 fig. 10, first foot; fig. 11, second foot (male); fig. 12, second foot (female); fig. 13, 

 abdomen and postabdominal ramus; fig. 14, copulative organs of male; fig. 15, muscle 

 spots. The figures of the shell magnified 50 diameters.] 



2. Argillcecia hadia, n. sp. (PL VI. fig. 3, a-d). 



Shell minute, compressed, ovate ; seen from the side, oblong, subovate, higher in 

 front than behind, greatest height situated in the middle, and equal to half the 

 length ; anterior extremity broadly rounded, posterior depressed, obliquely rounded ; 

 dorsal margin moderately arched, ventral almost straight ; seen from above, ovate, 

 acuminate in front, rounded behind, greatest width in the middle, and equal to rather 

 more than one-third of the length ; end view subcircular. Surface of the shell perfectly 

 smooth. Length, l-62d of an inch ('4 mm.). 



Dredged at Port Jackson, Australia, in 2 to 10 fathoms. 



[PL VI. fig. 3, a-d. a Shell seen from left side, b from above, c from below, d from 

 front, magnified 60 diameters.] 



Macrocyioris, G. S. Brady. 



Mao'ocypris, Brady, Monog. Eecent Brit. Ostrac, 1868. 



Bairdia (in part), G. O. Sars, Oversigt af Norges marin. Ostr., 1865. 



Carapace elongated, attenuated at the extremities ; valves unequal, the right larger 

 than the left, and overlapping dorsally ; hinge-line flexuous. Surface of the shell 

 smooth, polished, and destitute of hairs. Antennse short and robust ; the anterior 

 seven-jointed, tapering to the apex, bearing numerous short setse ; posterior five-jointed, 



