CKTISTACEA Oi* THE MEEGUI ARCHIPELAGO. 19 



the prolongation of the obhque surface of the anterior declivity 

 of the gastric region. In the largest specimen (15 millim. long), 

 a male, the cephalothorax is 10 millim. long ; so that the pro- 

 portion of the length of the cephalothorax to that of the rostral 

 spines is nearly as 15 to 7, whereas in H. Hilgendorjl this pro- 

 portion is as 15 to 11| ; the spines are thus comparatively 

 much longer in this species. The posterior cardiac lobe rises 

 into an acute spine. 



Genus Naxia, M.-Edw, 



6. Naxia (Naxioides) Peteesii, Hilgendorf. 



Podopisa Petersii, Hilgendorf, Monatsb. Acad. Wissensch. Berlin, Nov. 

 1878, p. 785, Taf. i. fig. 1-5. 



Naxia (Naxioides) Petersii, Miers, Report on the Zool. Collections made 

 in the Indo-Pacific Ocean during the Voyage of It.M.8. ' Alert,' 1884, 

 p. 523. 



A young female specimen of this species was forwarded to 

 Dr. Anderson from the Andaman Islands, and I therefore 

 include it. As it agrees completely with Hilgendorf 's description 

 and figure, I will only add the following remarks : — The spine 

 on the intestinal region appears rather obtuse, whereas in 

 Hilgendorf's adult specimen it is more acute. As in his speci- 

 men, the spines of the rostrum seem to be broken off; they 

 have almost the same length, are nearly parallel to one another, 

 and are comparatively shorter than in the specimen in the 

 Berlin Museum, for they do not reach aa far forward as the 

 peduncle of the external antennae. Each spine is armed on its 

 dorsal surface with a very small accessory spine, somewhat as 

 in Naxioides hirta^ A. M.-Edw. These antennal peduncles, which 

 in the Berlin specimen were unequally developed, are quite 

 equal to one another in the Andaman specimen ; their terminal 

 joint is little more than half as long as the penultimate joint, 

 and the flagella are scarcely so long as the two terminal joints 

 taken together. The flagella bear a few long hairs on their 

 inner side; and the two last joints of the peduncle are clothed 

 with many hooked hairs. 



The anterior legs are comparatively much smaller than in the 

 male, but present nearly the same form. The length of the 

 cephalothorax to the base of the rostral spines is about 26 millim., 

 and the distance between the tips of the posterior branchial 

 spines, indicating the greatest width of the carapace, amounts to 



2* 



