290 CARL BOVÄLLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPEKITD^,. 



Euthemisto libellula. 



male, in the adnlt it is a little lougev; tlie front margin is rainutel}' pectinated, and set 

 with bristles; the hind margin is armed with a few short spines. The dactylus is about 

 a fifth part as long as the metacarpus in the adult inale, in the young it is comparatively 

 inuch longer, being nearly half as long as the metacarpus; it is minutely pectinated at 

 the base of the fi-ont margin. 



The pleon is rancli longer than the whole perajon, and only a little shorter than the 

 head and perieon together. The under margin of the segments is feebly notched; the 

 hind corner is not produced, but sharp-pointed. 



The pleopoda (Pl. XIII, fig. 30) are long and slender, the rami are longer than the 

 peduncle; the outer ramus of the first pair has twenty-two joints, the inner twenty; in 

 the very 3'oung the number of joints is only the half. The coupling spines are robust 

 with a large head and three sharp, hook-like projections on the stem. The apically dilated 

 arm of the cleft bristle is a little shorter than the other; the basal part is thickly set 

 with long hairs. 



The urus is quite as long as the last pleonal segment; the first ural segment is 

 considerably longer than the last coalesced, which is a little broader than long, and shows 

 a deep incision on either side for the insertion of the second pair of iiropoda. 



The wvjjoda (Pl. XIII, fig. 31). The first jurir reach considerably beyond the apex 

 of the second pair, and nearly to the apex of the third. The peduncle is narrow, linear, 

 nearly seven times as long as broad, and only a trifle longer than the inner ramus; the 

 rami are narrowly elongated, sharp-pointed, and provided with semicircnlar incisions near 

 the base; the inner ramus is a little broader, and a third part longer, than the outer, it 

 is serrated along the outer margin and sraooth on the inner; the outer ramus is serrated 

 along the inner margin and smooth on the outer. In the young the first pair reach be- 

 yond the middle of the outer ramus of the third pair. The second pah' reach beyond 

 the apex of the peduncle of the last pair; the peduncle is broader below than above, 

 about four times as long as it is broad at the apex, and has the lower inner corner pro- 

 duced downwards into a sharp-pointed angle; the peduncle is a trifle longer than the inner 

 ramus, which is lanceolate, sharp-pointed, serrated on botli margins, and is twice as broad 

 as, and a about a fourth part longer than, the outer ramus; the outer ramus is serrated along 

 the inner margin and smooth on the outer. In the young the inner ramus is much 

 narrower than in the adult. The peduncle of the third pair is broad, linear, three and 

 a half times as long as broad, and has the lower inner corner produced downwards into 

 a sharp angle; it is about a third part longer than the inner ramus, which is lanceolate, 

 serrated on both margins, and is twice as broad as, and a little longer than, the outer 

 ramus; the outer ramus is serrated as in the second paii\ In the young the peduncle 

 is almost four times as long as broad, and the rami are narrower than in the adult. 



The telson is tongue-shaped, considerably longer than broad, and longer than the 

 last ural segment; it is as broad, and not full}- half as long, as the peduncle of the 

 last pair of uropoda. 



