Mr. A. White on some new genera of Crustacea. 177 



each side of it, outside the eyes, there is a knob which makes the 

 anterior part of the carapace angular. 



Xanthasia murigera, White. PL II. fig. 3. Of an ochraceous 

 white. Carapace above, with the margin, excepting in front, 

 raised into an elevated ridge, which is curled round behind the 

 lateral knob on the front of the carapace : on the middle of the 

 back of the carapace there is an elevated tubercle with the lateral 

 edges sharp and the upper surface rough ; between this and the 

 front are two parallel elevated keels placed longitudinally. 



Hah. Philippine Islands. British Museum ; collected by Mr. 

 Cuming. The figure is of the natural size. 



Pinnixa, White. At once distinguished from Pinnotheres by 

 its carapace being much wider than long. First pair of legs with 

 the hand more elongated ; second pair of legs slender, somewhat 

 compressed ; third pair also compressed, somewhat stouter than 

 the preceding; fourth pair very large, the third joint much 

 thickened, behind somewhat dilated and deeply grooved near the 

 posterior edge ; the fifth or tibial joint finely serrated on the in- 

 side ; last pair of legs small and of the same form as the second. 



Tail of the female at the base narrowed, leaving a considerable 

 space between its edge and the insertion of the three last pairs of 

 hind-legs. 



Pinnixa cylindrica. Pinnotheres cylindricum, Say, Journal of 

 the Academy of Sciences of Philadelphia, i. p. 452. 



Hah. Georgia, U. S. (on Jeykill Island). British Museum. 



Family ? 



Xenophthalmus, White. Carapace wider than long ; the back 

 regularly arched, rounded on the front edges ; the front with a 

 wide notch, in which are two slits, the bottom of each containing 

 one of the eyes ; eyes small, seen from above, separated from the 

 antennae by a somewhat cylindrical tooth which runs across the 

 slit ; front blunt ; outer foot-jaws with the second joint deeply 

 grooved on the outside, which groove extends to the basal joint ; 

 carapace on the under side hollowed out above the branchial 

 opening, which is long and very open, the two edges furnished 

 with long stiff hairs meeting at the end, much as in Dorippe. 



Tail of the male 7-jointed, third joint widest, fifth joint nar- 

 rowed near the base. 



Tail of the female with the fourth and fifth joints of the same 

 width ; a long ciliated process proceeding from each side of the 

 third joint. 



First pair of legs of the male with the hands somewhat elon- 

 gated and thickened ; second pair of legs with the different joints 

 angled, the tarsus dilated at the base and somewhat serrated 

 on the edge ; third pair of legs with the tibial joint and that 



Ann. §• Mag. N. Hist. Vol. xviii. 



