OSTEACODA. 7 



(fig. 5), pointed in front, broadly rounded behind, the lateral margins very boldly 

 arcuate, greatest width situated behind the middle and equal to two-thirds of tin- 

 length. The surface of the shell is smooth, deep ochreous yellow in colour, with a 

 conspicuous dark eye-spot within the dorsal margin near the front, just below and 

 behind which there is a large irregularly shaped pellucid, sub-circular patch, and belo\v 

 this again a series of four oblong muscle spots, arranged in a transverse curve, and 

 in front of these two smaller spots the long diameters of which lie in the opposite 

 direction. The left valve is the larger of the two, overlapping the right both in front 

 and behind. Length 0'65 mm. The shell of the female is somewhat more tumid, 

 and seen from the side has no ventral sinuosity ; it is also almost free from anterior 

 depression, the two extremities being nearly equal in width. 



Two specimens only of this small species were seen, a male and a female ; the 

 female, however, was only an empty shell and was quite colourless. The exact locality 

 of the capture I do not know. The specimens were accidentally discovered in a 

 flocculent diatomaeeous deposit which settled from the liquid in which the larger 

 Cypridinidse had been preserved. The fiexuous lateral contour of the male distinguishes 

 this from any other species of Xestoleberis known to me. 



LINOCHELES.* 



Differing from the typical Cytheridse in the greatly elongated and thread-like legs 

 of the third pair, and in the abnormally formed copulatory plate of the male. 



LINOCHELES VAGANS. 

 (Plate III., figs. 11-18.) 



Shell closely similar in shape to Xestoleberis; seen laterally (fig. 11) that of the 

 male is subreuiform, greatest height situated behind the middle and equal to much 

 more than half the length ; anterior extremity narrow and obliquely rounded, posterior 

 very wide and evenly rounded, dorsal margin boldly arched, steeply curved posteriorly, 

 sloping with a gentle curve to the front, ventral margin sinuated in front of the 

 middle ; seen from above, the outline is elongated, ovate ; widest in the middle 

 (fig. 12), width rather less than half the length, narrowed and obtusely pointed in 

 front, broader and rounded off behind. Shell-surface perfectly smooth ; colour brown. 

 Length, 64 mm. 



Antennules six-jointed, very sparingly setiferous (fig. 13) ; antennae short and 

 stout, with short apical claws and a stout urticating seta which reaches to the apices of 

 the claws (fig. 14). First and second pairs of legs (figs. 15, 16) armed with short and 

 stout terminal claws; third pair much elongated (fig. 17), the last joint extremely 

 slender and much longer than the united lengths of the two preceding joints ; terminal 



* Aii'iir, a thread ; x>;An, a claw, 



I, L> 



