1887.] G. M. Griles — SiiC new AmpMpods from the Bay of Bengal 227 



The form (the EypeHa-8tQ.ge) figured on PI. VI. was obtained on the 

 same occasion as the Lestrigonus bengalensis. The specimens were about 

 equally divided between the sexes ; and I have little doubt that the 

 males (Fig. 1.) are merely a young stage of this species, as they agree in 

 all essential particulars save the smaller development of the flagella of 

 the antennae. Even here the difference lies only in the smaller length of 

 the individual joints and not in their number. Seen apart from the 

 more fully developed forms, they would certainly be assigned to the 

 genus Hyperia, especially some specimens, smaller than that figured, in 

 which the antennae are even shorter. If this supposition be correct, 

 distinctions between Hyperia and Lestrigonus can hardly, as already 

 advanced, be of generic value. Whether or not all male Hyperia ulti- 

 mately develop a long flagellum is of course doubtful, but there can be 

 little doubt that all Lestrigonus pass through an Hyperia-sisige. Speak- 

 ing generally, the Hyperia-sisbge is shorter and stouter and more like 

 the female (Fig. 3.) described below. In this specimen, I could clearly 

 make out three gill-sacs attached to the 4th, 5th, and 6th thoracic 

 segments. I was more fortunate, too, in the dissection of the gnathites 

 in the younger than in the adult specimen ; and a glance at the in- 

 complete figures of those of the adult form as compared with those 

 of the more completely figured Hyperia-sisige confirms the opinion as to 

 the identity of the two forms. With the exception of the antennse, the 

 appendages are practically identical in both, save that in the younger 

 form they are proportionally a trifle shorter than in the adult. 



The female, in general form, closely resembles the young male ; she 

 is, however, shorter, but more stoutly built, the very short thoracic seg- 

 ments being of remarkable depth. The principal external difference 

 between the sexes lies in the antennae, which, in the female, are 

 remarkably ill developed. In the antennules, there is a three-jointed 

 peduncle, practically identical with that of the male, but the flagellum 

 is reduced to a rudimentary first joint. The antennce are reduced 

 to a rudiment of the basal joint of the peduncle. All the females 

 collected carried in a well-developed brood-pouch a number (about 18 

 or 20) of largish (6*25 m.) ova, none of which had gone beyond the stage 

 of segmentation. The length of the specimen figured is 1*75 m.m. 



§ 5. EURTSTHEUS HIESUTUS, n. sp., PI. VIII. 



The species described below was taken on the same occasion as 

 Lestrigonus bengalensis. It is nearly transparent and, saving a few 

 scattered patches of reddish brown pigment, colourless. Only a single 

 specimen was obtained. 



The animal is 4 m.m. long. 



