302 CARL BOVALLIUS, AMPHIPODA HYPERI1UEA. I. 2. HYPERIII)^;. 



Euthemisto Gaudichaudii. 



The head is less rounded than in Euthemisto libellula and E. antarctica, with the 

 front margin almost obliquely truncated, and the under margin thus being very short. 

 The antennal groove is broader above than below. 



The first pair of antenna are very short, and reach a little beyond the hind margin 

 of the fourth pergonal segment. The first joint of the peduncle is half as long again as 

 the two following joints together. The first joint of the fiagellum is tumid, with the 

 upper margin strongly convex; it is more than twice as long as the whole peduncle; the 

 second joint is very short, broader than long; the third is somewhat longer than broad; 

 the fourth is as long as the two preceding together; the fifth, sixth, and seventh joints 

 increase in length; the following are longer, and are subequal in length; the last joint is 

 ten times as long as broad. The flagellar joints are thirteen in number. 



The second pair of antennae are longer than the first, and reach beyond the hind 

 margin of the last perasonal segment. The second peduncular joint is longer than the 

 first; the third is as long as the two preceding together. The first joint of the flagellum 

 is somewhat shorter than the last peduncular joint; the second and third are short; the 

 following are longer, subequal in length; the last four decrease slowly in length; the last 

 joint is eight times as long as broad. The flagellar joints are twenty in number. 



The mouth-organs are like those in Euthemisto libellula. 



The perceon. The first segment is much longer than the second; the seventh is the 

 longest of all. The dorsal carina is very distinct, and in adult males it is usually pro- 

 jecting in a small angle on the fifth segment and in a larger on the sixth and seventh. 



The epimerals are not deep; that of the fifth pair is about four times as long 

 as deep. 



The branchial sacks are comparatively larger than in Euthemisto libellula; they are 

 broadest at the middle. 



The first pair of peraiopoda. The femur is almost linear, and is considerably 

 longer than the three following joints together. The produced lower part of the tibia 

 is eniarginate, showing a small projection, and is fringed with long bristles. The carpus 

 is longer than the two preceding joints together, and has the front margin set with long 

 hairs, and the hind margin notched and armed with long bristles. The metacarpus is 

 fully as long as the carpus; the convex front margin is fringed with long, hair- like bristles; 

 the hind margin is serrated, and has a single stout bristle a little below the middle. The 

 dactylus is curved, and more than half as long as the metacarpus. 



The second pair ((PI. XIII, fig. 44) are only a trifle longer than the first. The 

 femur is a little shorter than the four following joints together. The tibial process is 

 emarginate at the apex, and is more than half as long as the stem of the carpus in the 

 adult male, a little shorter in the young, and is thickly set with long bristles. The carpal 

 process in the adult male is nearly as long as the hind margin of the metacarpus, and is 

 provided with a terminal spine; in the young it is shorter, but still more than half as 

 long as the metacarpus. The metacarpus is as long as the stem of the carpus, and has 

 the front margin densely set with long, hair-like bristles; the hind margin is finely 

 pectinated. The dactylus is almost straight, and is half as long as the metacarpus. 



