262 CARL BOVALLIUS, AMPHIPODA HYPERI1DEA. I. 2. HYPERIID^;. 



Parathemisto japonica. 



notched, and provided with a few short bristles. The metacarpus is long, slender, quite 

 as long as the two preceding joints together; in the sixth pair it is a little longer; the front 

 margin is somewhat concave, it is finely pectinated, and provided with bristles; the hind 

 margin is set with short bristles. The dactyl us is long and slender; in the sixth pair 

 it is nearly a third part as long as the metacarpus; in the fifth pair it is serrated at 

 the base on the front margin, while it is smooth in the sixth and seventh pairs (PI. XII, 

 fig. 38 and 41). 



The pleon is longer than the last five pera3onal segments together. The lateral 

 parts of the segments are obtusely rounded behind. 



The pleopoda have the rami long and slender. In the first pair each ramus has 

 fifteen joints. The coupling spines are hook-shaped, with two sharp teeth on the side 

 of the stern; the cleft bristle has the apically dilated arm a little shorter than the other. 



The urus. The first segment is about as long as the last coalesced, which is twice 

 as broad as long. 



The uropoda (PI. XII, fig. 43). The first pair reach beyond the middle of the outer 

 ramus of the last pair; the peduncle is linear, four times as long as broad, and quite as 

 long as the inner ramus, which is a third part longer than the outer; both rami are 

 elongated, and sharp-pointed; the inner is serrated on the outer margin; the outer ramus 

 is serrated on the inner margin. The second pair reach a little bej^ond the apex of the 

 peduncle of the last pair; the peduncle is narrower at the base than at the apex, with 

 the lower inner corner strongly produced downwards; the inner ramus is a little shorter 

 than the peduncle, and is longer than the outer ramus; it is irregularly lanceolate and 

 serrated on both margins; the outer ramus is much narrower than the inner, is sharp- 

 pointed, and serrated along the inner margin. The peduncle of the third pair is linear, 

 three times as long as broad, and has the lower inner corner produced as in the second 

 pair; the rami are equal in length, and as long as two-thirds of the peduncle; the inner 

 is broader than the outer, and is serrated on both margins; the outer ramus is serrated 

 on the inner margin. 



The telson is as long as broad, fully as long as the last ural segment, and more 

 than a third part as long as the peduncle of the last pair of uropoda. 



The female. 



PI. XII, fig. 17—21, 39 and 40. 



The forepart of the body is wider than in the male; the pleon and urus together 

 are shorter than the peraeon. 



The first pair of antenna? (PI. XII, fig. 18 and 19) are somewhat longer than the 

 head and the first peraeonal segment together. The first joint of the peduncle is more 

 than twice as long as the two following joints together. The single flagellar joint is con- 

 siderably more than twice as long as the whole peduncle; the basal portion is conical, with 

 somewhat bulging sides, the under margin is serrated, and provided with long olfactory 

 hairs (PI. XII, fig. 19); the flagellum is slender, cylindrical, and entirely smooth for the 

 last two thirds of its length. 



