126 THE VOYAGE OF H.M.S. CHALLENGER. 



This species is more slender in outline than any other with which I am acquainted, 

 excepting, perhaps, Xestoleheris intermedia, Brady (Mediterranean) ; and Xestoleberis 

 labiata, Brady and Eobertson (British), from which latter, however, it differs somewhat 

 in shape as well as in the want of the peculiar labiate prolongation of the shell from 

 which the British species takes it name. 



[PL XXX. fig. 5, a-d. a Shell seen from left side, b from above, c from below, d 

 from front. Magnified 50 diameters.] 



4. Xestoleheris nana, n. sp. (PL XXXL fig. 5, a-c). 



Carapace very tumid ; as seen from the side, sub-semicircular, highest near the middle ; 

 extremities obliquely rounded, dorsal margin boldly arched, ventral nearly straight, 

 height equal to more than half the length ; seen from above the outline is very broadly 

 ovate, subacuminate in front, broadly rounded behind, greatest width in the middle, and 

 equal to nearly three-fourths of the length ; end view depressed, the width much greater 

 than the height. Surface of the shell perfectly smooth. Length, 1-5 8th of an inch 

 (•45 mm.). 



Found in a dredging, from a depth of 18 fathoms, off Tongatabu, coral bottom 

 (Station 172). 



[PL XXXL fig. 5, a-c. a Carapace seen from left side, h from below, c from front. 

 Magnified 50 diameters.] 



5. Xestoleheris africana, n. sp. (PL XXX. fig. 4, a-c). 



Carapace very tumid ; seen from the side, broadly subovate, height greatest a little 

 behind the middle, and equal to about three-fourths of the length ; obliquely rounded, 

 and somewhat narrowed in front, broad, and well rounded behind, dorsal margin boldly 

 arched, ventral decidedly convex ; seen from above broadly ovate, widest in the middle, 

 abruptly tapered and subacuminate in front, rounded behind, width equal to two-thirds 

 of the length ; end view subcircular, base somewhat emarginate ; height greater than the 

 width. Surface of the shell smooth, slightly papillose. Length, l-50th of an inch ("5 mm.). 



Dredged in Simon's Bay, South Africa, in a depth of 15 to 20 fathoms. (Station 

 140.) 



[PL XXX. fig. 4, a-c. a Carapace seen from left side, h from below, c from front. 

 Magnified 60 diameters.] 



6. Xestoleberis curta, G. S. Brady (PL XXXL fig. 6, a-d). 



Gytheridea (?) curta, Brady, Trans. Zool. Soc, 1865, vol v. p. 370, pi Iviii. fig. 7, a-b. 

 Xestoleheris curta, Brady, Les Fonds de la Mer, p. 79, pi. x. figs. 16--18 {Ico7i. mal). 



Carapace, as seen from the side, oblong, subovate, greatest width situated behind the 

 middle, and equal to more than half the length ; extremities well rounded ; dorsal margin 



