226 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPERIIDJE. 



Hyperia erucipes. 



Hyperia erucipes is remarkable for the armature of the dactylus of the fifth and 

 sixth pairs of pera^opoda, which easily distinguishes it from all its congeners, and also for 

 the deeply produced lower part of the head, which feature it has in common with H. 

 schizogeneios. This process extends straight downwards in both species, but it is broad, 

 almost truncated in H. erucipes, while it is acute in H. schizogeneios. Moreover the 

 considerable elongation of the carpal process of the first and second pairs of perseopoda 

 is a good characteristic for the distinction of this species from its nearest relative. 



The male. 



PI. XI, fig. 17—19, and 21—23. 



The body is tolerably broad; the head and person together are longer than the 

 pleon and urus together. The integument is very thin and almost hyaline, at least in 

 the peraeonal segments. 



The head is fully as long as the coalesced portion of the perseon. The antennal 

 groove commences a little below the middle of the front side, and is very deep. 



The first pair of antennae reach nearly to the hind margin of the first pleonal 

 segment. The first joint of the peduncle is more than twice as long as the two follow- 

 ing joints together. The first joint of the flagellum is shorter than the peduncle; the 

 second and third joints are very short; the following are long, cylindrical, subequal in 

 length, and about eight times as long as broad. The flagellar joints are fifteen in number. 



The second pair of antenna? are about as long as the first. The first free joint 

 of the peduncle is as long as broad, and only a little longer than the glandular cone; 

 the third joint is as long as the two preceding together. The first joint of the flagellum 

 is nearly as long as the last peduncular joint; the following are shorter, cylindrical, sub- 

 equal in length, and about six times as long as broad. The flagellar joints are sixteen 

 in number. 



The perceon. The coalesced portion of the pera?on is not fully as long as the 

 following three segments together; the seventh segment is a third part longer than the 

 sixth. The peraeon is scarcely longer than the pleon and urus together. 



The first pair of peroeopoda (PI. XI, fig. 17 and 18). The femur is nearly as 

 long as the four following joints together; the hind margin is feebly convex; the front 

 margin forms an obtuse angle in the middle. The tibia is produced at the lower hind 

 corner, and armed with two bristles. The carpus is very broad, about as broad below 

 as it is long; the carpal process is about a third part as long as the stem of the carpus, 

 and its front side is fully half as long as the hind margin of the metacarpus, the mar- 

 gins being fringed with long bristles. The metacarpus is somewhat longer than the 

 carpus, and is more than twice as long as broad at the base; the front margin is convex 

 and smooth; the hind margin is sharply serrated, and armed with four tolerably long 

 spines. The dactylus is feebly curved, and is not half as long as the metacarpus; the 

 hind margin is serrated. 



