28 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. PARAPHRONIMID^. 



Paraphronima gracilis has the body more slender, and the legs comparatively 

 longer and narrower than the two following species, the head is longer and deeper, the 

 peduncles of the uropoda are also a little more elongated. From P. pedestris it differs 

 chiefly by the large head and the comparatively short carpi of the last five pairs of perseo- 

 poda. The male is stouter than the female. 



The integument of the body is very thin, hyaline, without ridges or impressions. 



The head is almost cubical with rounded corners; at the anterior side there is a 

 shallow groove where the first pair of antenrne are fixed. The under-side is evenly con- 

 cavated. From a lateral view the under-margin is almost straight. The head is fully 

 twice as deep as the first pergonal segment and in the male as long as, in the female a 

 little longer than the first four pergonal segments. 



The eyes consist of larger and more distant ocelli than in the preceding families. 

 The ocelli are divided into two distinct agglomerations on each side of the head, one 

 much larger in the middle, and one small near the under-side. 



The first pair of antennw (PI. II, fig. 2) are straight, much longer and stouter in 

 the male than in the female. In the male they are almost as long as the head, in the 

 female they equal about a third of the length of the head. The first joint of the peduncle 

 is longer than the two following together, the second is longer than the third. The first 

 joint of the flagellum reminds in shape of that joint in the genus Vibilia, in the male it 

 is elongate-lanceolate, about four times longer than the peduncle; in the female the first 

 joint is scarcely twice as long as the peduncle. The inner-side of this joint is richly 

 fringed with long hairs and stout olfactory bristles. The second and third joints of the 

 flagellum are usually distinct, but very minute, the second longer than the third. 



The second pair of antennce, (PI. II, fig. 3) are fixed closely in front of the mouth- 

 organs at the hind corner of the under-side of the head. They consist in the male of 

 five joints, the first joint is very short, coalesced with the head, and protuding as a round 

 tubercle, at the side of it is a large, circular opening for the gland contained in this joint, 

 the second joint is nearly as long as the head, fringed with short, club- like, glandular hairs; 

 when at rest this joint is concealed in the above-mentioned groove at the under-side af 

 the head. The third and fourth joints are short, equal in length, the fifth is about twice 

 as long as the two preceding joints together, much narrower, linear, fringed with hairs. 

 The articulation between the second and third joint permits the terminal part of the 

 antenna 1 (the flagellum?) to be folded up along the under-side of the long second joint. 

 In the female the second pair of antenna 1 consist of only two joints, the basal one short, 

 the terminal five times longer, tapering, carrying a bristle at the apex. 



The mouth-organs will be described below, under Paraphronima clypeata, they offer 

 no differences in the three species. 



The perceon is more convex in the female than in the male. The first and second 

 segments are the shortest, the seventh the longest. 



The epimerals are not separated from the segments, but are represented by the 

 abruptly narrowing lower end of each segment. At the inner side of this narrow projection 

 articulates the femur of the corresponding leg. 



