1G CEYLON PEARL OYSTER REPORT. 



given of the male, leaves only a few points needing to be submitted or explained. 

 The flagellum of the second antennae has in our specimen ten joints instead of twelve. 

 The epistome and upper lip I did not clearly make out. Hansen does not call 

 attention to the almost complete smoothness of the three seta? on the inner plate of 

 the first maxillae. The second maxillae have three spines on the outermost plate and 

 four on its companion. In the second pleopods the inner ramus is narrow and has the 

 male appendix attached about one-third of its length from the base, reaching beyond 

 both rami, and having apparently a bifid apex. The first four pairs of pleojDods have 

 setae on both rami ; the fifth pair escaped observation. In the telsonic segment, 

 which is covered with squamose markings rather more conspicuously than the rest 

 of the body, the three dorsal carinae are clearly developed. But here the lateral pair 

 appear to run without divergence and none of the three quite reach the margin of the 

 segment, in these respects differing from the female represented by Hansen. 

 According to Hansen the apex is not spinose, and he says the same of the uropods. 

 In our specimen both the segment and its appendages carry several minute spines, 

 which are only visible under high magnification. This is also the case in a specimen 

 sent me from Antigua by W. R. Forrest, Esq. 



In the first gnathopods the spines on the inner margin of the broad hand show a 

 variety of minute deuticulations. In this and the other limbs the point of junction 

 between nail and finger is marked on the convex margin by a group of microscopic 

 setules. The first gnathopods cannot claim to be subchelate, though otherwise by 

 breadth and compactness they make some approach to the corresponding limbs in 

 //. cmisopous. But, whereas in that species the two following pairs are very 

 differently and more slenderly constructed, here they show a very near agreement, in 

 all three pairs the fifth joint underriding the sixth. 



Length scarcely 3 millims., breadth 1*5 millims., the proportion being 27:14, 

 Hansen's specimen was 4 - 25 millims. long. 



Locality : Among compound Ascidians and with other Isopods at Reef, Galle. 



The small size and deceptive appearance of this species, rather than any actual 

 rarity or any marvel of distribution, may account for the fact that the East Indies 

 have now revealed a solitary specimen of the male fourteen years after the West 

 Indies had disclosed a solitary specimen of the female. 



Family : AEGATHONID^, nov. 



Mandibles, with cutting edge bidentate or simple ; molar represented by a feeble 

 blade, not serrate. First maxillae with inner plate broadly truncate, outer strongly 

 produced, ending in an unguis with a small curved spine at its base. Second maxillae 

 very short, ending in a broadly rounded single lobe. Maxillipeds six-jointed, second 

 joint not elongate, fourth and fifth joints fused together, seventh well-developed, 

 blunt. Male appendix of second pleopods affixed at the base of the ramus. 



By the character of the mandibles this family offers a connecting link between the 



