PHILORTHRAQORISCUS SERRATUS. 139 



extending beyond the posterior extremity of the genital 

 segment. It is two-jointed , and consists of a small ellip- 

 tical basal joint and another one , that is of a reversed tra- 

 pezoidal shape, with rounded anterior angles and a shal- 

 low notch in the middle of the posterior margin; it is 

 nearly twice as broad as long. There are two short, ob- 

 tuse conical caudal stylets , bearing six terminal setae. 

 Foliate appendages , as there occur three in Dinematicra 

 and a single one in Echthrogaleus could not be found. 



The egg-sacs are very long and measure about five times 

 the length of the whole body. 



The anterior antennae (fig. 1) are two-jointed and much 

 resemble those of Dinematura and Echthrogaleus; however 

 the apical joint in our species is somewhat longer and 

 even exceeds in length the basal joint, in this regard 

 more agreeing with Liitkenia, found by Claus on the gills 

 of Asterodermus coryphaenoides '). Besides some short ter- 

 minal setae the apical joint also bears another seta in the 

 middle of the ventral side, the basal joint is provided on 

 its dorsal side with a kind of ridge, extending over about 

 half its length , which bears an external row of long ci- 

 liose setae and an internal row of short spines. 



The posterior antennae (fig. 2) much agree with those 

 of Echthrogaleus coleoptratus ; they consist of three joints : 

 a cylindrical basal joint, a truncate conical second one, 

 and the terminal claw. Kröyer erroneously speaks of three 

 basal joints and the claw, but I presume that he mistook 



1) Zeitschr. f. wissensch. Zoölogie, Bd. XIV, 1864, p. 369, pi. 34. 



I think Gerstacker (Bronn, Bd. V, Crustacea, p. 723) is not quite right, 

 when he ranges Liltkenia among the Caligina, stating /.nur das erste Paar 

 der Spaltbeine einastig", for Claus himself points out the affinity of his new 

 genus with Echthrogaleus and Dinematura and he says with regard to the first 

 pair of swimming feet, that though it «eine zu der Gattung Caligus hinführende 

 Umbildung erleidet, allerdings die heiden Aeste ihre zwei Glieder behalten." 

 Also it appears somewhat dubious to me, that Lütkenia should be identical 

 with Cecropsina, which has the genital segment deeply clefted and the swim- 

 ming feet „setis terminalibus brevissimis instructi", whereas in Lütkenia yet 

 the second and third pairs of feet are «setis plumosis instructi". 



Notes from the Leyden Museum, Vol. XIX. 



