Amphipoda Synopidea. 17 



The body is not very arched, almost straight. 



The head is triangular seen from above, l)nt nearly rectangular 

 seen from the side, a little shorter than the first four pereional seg- 

 ments. The excavation for the insertion of the antennae is very large, 

 deeper than half the depth of the head. 



The median eye is very broad, not circular; the number of peri- 

 phorical ocelli is about thirty, those of the hinder margin are indistinct. 

 The small secondary eyes are situated very close to the median eye. 



The first pair of antenncc [PI. II, fig. 23] reach quite to the anterior 

 margin of the second pleonal segment. The last joint of the peduncle is 

 scarcely as long as a third of the second. The flagellum consists of 16 

 joints, the first much the longest, as long as the four following ones to- 

 gether, beset with long hairs; the following are totally smooth, except 

 the last, which carries a long terminal hair. The secondary flagellum 

 is two-jointed, shorter than the first joint of the true flagellum. 



The second pair of antennce [PL II, fig. 24] are similar in struc- 

 ture to those of S. ultramarina, but the articuli of the flagellum are 

 longer and more setose. 



The pereion. The fifth and sixth segments are equal, the seventh 

 the longest, as long as the first two together. 



The epimerals [PL II, fig. 22] resemble very closely those of S. 

 ultramarina. 



The first imir of pereiopoda [PL II, fig. 25] differ from the same 

 pair in S. ultramarina only in very unimportant details, as the carpus 

 being proportionally longer, the plumose hairs also longer, as long as 

 the breadth of the joint, and the dactylus shorter, equalling only two 

 thirds of the length of the metacarpus. 



The second pair [PL II, fig. 26] are of the same form as in S. 

 ultramarina, the bristles of the carpus and metacarpus are a little longer 

 and stronger. 



The third 'pair [PL II, fig. 27]. The femur is shorter than the epi- 

 meral is deep. The tibia is longer than the carpus; the tibia and car- 

 pus together are longer than the femur. The anterior margin of the 

 tibia is fringed with minute hairs. 



The fourth pair [PL II, fig. 28]. The carpus is almost twice as 

 long as broad; both tibia and carpus are filled with a glandular mass, 

 a little of which is to be seen also in the metacarpus. The metacarpus 

 is half as long as the carpus, the hinder margin fringed with 10 — 12 

 very long, plumose hairs, longer than the joint itself. 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 3 



