256 CARL BOVALLIUS, AMPHIPODA HYPEHIIDEA. I. 2. HYPERIIO^. 



Parathemisto oblivia. 



and is considerably longer than the carpus; the front margin is strongly convex, and 

 smooth; the hind margin is almost straight, finely serrated, and forming a thin edge which 

 impinges against the hind margin of the carpus; at the base of this edge there is on the 

 outer side of the joint a row of long slender bristles. The dactylus is about two-thirds 

 as long as the metacarpus, nearly straight, slender, and sharp-pointed. 



The fifth, sixth, and seventh pairs (PL XII, fig. 15) are similar in shape, and equal 

 in length. The femur is quite as long as the femur of the fourth pair; the front margin is 

 irregularly convex, with six or seven short bristles along its lower half, and with the lower 

 corner a little produced; the hind margin is straight, with the lower corner squared; the 

 femur is considerably shorter than the three following joints together. The genu is a 

 little longer than broad, with a few short bristles on the front margin. The tibia is 

 more than twice as long as the genu; the front margin is straight, and is provided with 

 five or six minute spines; the hind margin is feebly convex, smooth, and has an apical 

 spine at the lower, somewhat produced corner. The carpus is narrow, linear, and fully 

 twice as long as the tibia; the front margin is straight, finely serrated, with minute, 

 spine-like teeth, and four or five long, equidistant bristles; the hind margin is almost 

 straight, with four bristles below the middle. The metacarpus is quite as long as the 

 two preceding joints together, slender, and feebly curved; the somewhat concave front 

 margin is finely serrated as in the preceding joint, and has eight or ten equidistant 

 bristles; the convex hind margin has two or three short, spine-like bristles. The dac- 

 tylus is long and slender, entirely smooth, and a third part as long as the metacarpus. 



The pleon is a little shorter than the last six pergonal segments together. The 

 dorsal keel is more distinct than in the peraaon. The lateral parts of the segments have 

 the hind corner outdrawn into a very short but sharp point. 



The pleopoda are narrow and slender; the outer ramus of the first pair has thirteen 

 joints, the inner twelve. 



The urus, without the telson, is shorter than the last pleonal segment; the first seg- 

 ment is about as long as the last coalesced. 



The uropoda (PL XII, fig. 16). The first pair reach a little beyond the middle of 

 the inner ramus of the last pair. The peduncle is narrow, linear, about six times as 

 long as broad, and is about a fourth part longer than the inner ramus; the rami are 

 elongate, sharp-pointed; the inner is not twice as long as the outer, with the inner 

 margin smooth and the outer finely serrated; the outer ramus has the inner margin 

 finely serrated, and the outer smooth. The second pair reach scarcely beyond the apex 

 of the peduncle of the last pair; the peduncle is narrower than in the first pair, longer 

 than the inner ramus, and has the lower inner corner sharply produced downwards; the 

 rami are serrated as in the first pair, the inner is longer than the outer. The third pair 

 have the peduncle twice as long as the last coalesced ural segment, and somewhat more 

 than three times as long as the telson; it is linear, somewhat broader than that in the 

 first pair, and fully four times as long as broad; the lower inner corner is produced into 

 a long, sharp-pointed process; the rami are elongate-lanceolate, and are serrated as in 

 the first pair; the inner ramus is only a little longer than the outer. 



