314 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPERIID.E. 



Themistella Sleenstrupi. 



twice as long as the two following joints together; the second joint is longer than the 

 third. The first joint of the flagellum is about as long as the whole peduncle; it is un- 

 usually tumid, with the under portion bulging out, and thickly covered with long olfactory 

 hairs; the second flagellar joint (PI. XIII, fig. 50) is about as long as broad, and has the 

 lower front corner projecting into a tumid process, which reaches to the middle of the 

 third joint, and carries three pairs of long olfactory hairs, fixed on large, ovate discs; the 

 last of these pairs of hairs are club-shaped, the two preceding pairs are slender. The third 

 flagellar joint is longer than broad, and has the under portion projecting into a tumid, bulging 

 process, which lies pressed against the inside of the joint; this process is armed with three 

 pairs of long, club-shaped hairs (PI. XIII, fig. 49). The fourth joint is longer than the 

 two preceding together, slender and cylindrical, the following are subequal in length, but 

 slowly tapering towards the apex. The flagellar joints are twenty-four in number. 



The second pair of antennce (PI. XIII, fig. 51 and 52) are longer than the first, and 

 a little longer than the whole animal. The first free joint is about as long as broad, and 

 a little longer than the second; the third joint is nearly as long as the two preceding 

 joints together, but is much more slender; the following joints are shorter than the first, 

 subequal in length, and each carries a short hair on the under side. The last joint is 

 tipped with two long hairs, and is more than twenty times as long as broad. The 

 flagellar joints are twenty-one in number. 



The peroeon is scarcely more than twice as long as the head, and is quite as long 

 as the first two pleonal segments together. The first and second segments are coalesced. 

 The seventh segment is the longest of all. 



The epimerals are not separated from the peraeonal segments, but coalesced with them. 



The branchial sacks are egg-shaped, and are shorter than the femora of the cor- 

 responding pairs of pereeopoda. 



The first pair of peraiopoda (PI. XIII, fig. 53) are scarcely shorter than the second. 

 The femur is almost as long as all the following joints together; the front margin is 

 strongly curved, the hind margin is nearly straight. The genu is broader than long, and 

 has a stout bristle at the lower hind corner. The tibia is longer than the genu, and 

 carries two or three bristles on the under margin. The carpus is shorter than the two 

 preceding joints together, the front margin is smooth, the hind margin is armed with a 

 stout bristle; the carpal process is narrowly spoon-shaped, provided with three bristles, and 

 is scarcely more than half as long as the stem of the carpus; the front side of the pro- 

 cess is more than a third part as long as the hind margin of the carpus. The meta- 

 carpus is much longer than the stem of the carpus; the front margin is convex, and 

 armed with two bristles below the middle; the hind margin is straight, and indistinctly 

 serrated. The dactylus is curved, and is half as "long as the metacarpus. 



The second pair (PI. XIII, fig. 54) reach to the apex of the carpus in the third 

 pair. The femur is narrower than in the first pair, and is broader below than above; it 

 is nearly as long as all the following joints together. The genu is considerably broader 

 than long. The tibia is a little produced at the lower hind corner, which is fringed with 

 short, spine-like bristles. The carpus, without the process, is about as long as the two 

 preceding joints together; the front and hind margins are smooth; the carpal process is 



