435 



by two specimens from Stat. 104, I now come to the conclusion that this so-called variety 

 is in reality a different species. This species is now identified with some doubt with Dana's 

 A. euchirus from the Strait of Balabac, with some doubt because Dana makes no mention 

 of the hairy crest at the inner side of the dactylus of the small chela of the male, in 

 the second place because in Dana's figure 6d that chela appears somewhat high er with 

 regard to its length than in the "Siboga" specimens and finally because the meri of the 3 ld 

 and 4 th . legs are armed with a mucli s t r o n g e r tooth than that of Dana's figure 6 ƒ. The 

 specimens collected by the "Siboga" appertain, however, probably to that species which is 

 regarded by Coutière as A. euchirus Dana, a young female of which species from Djibouti 

 is lying before me for which I am indebted to that distinguished Carcinologist : I say probably, 

 because the tooth on the merus of the 3 ld legs appears in that female smaller than in our 

 specimens of the same size. The largest specimen, the male from Stat. 50, is 25,5 mm. long, 

 this species, however, attains the length of 34 mm. At either sicle of the rostrum the frontal 

 margin bears a rounded prominence, separated by a concavity from the rostrum and which 

 prominence appears in a lateral view as an acute point, just as in Dana's figure 6«; this 

 prominence, which is well developed in the male from Stat. 50 and in other individuals, is 

 sometimes less conspicuous. Telson as in A. Hippothoë. 



Both chelipeds are armed with a spine at the apex of the infero-internal margin of their 

 meri. The large chela of the male from Stat. 50 that closely agrees with Dana's figure 6<r, is 

 one and a half as long as the carapace without the rostrum, 2,5-times as long (13 mm.) as high 

 or broad (5,2 mm.) and the fingers are almost half as long (4 mm.) as the palm (9 mm.). The 

 large chela of the male has a more si en der form than that of A. Hippothoë. The notch 

 on the lower border is less deep than in A. Hippothoë and while in both species the groove 

 on the outer face of the palm is triangular, it appears quadrangular in A. edamensis. 



In the adult male from Stat. 50 the stout carpal segments of the 2 nd legs are 2,3 mm., 

 1,2 mm., 0,56 mm., 0,54 mm. and 0,9 mm. long; chela 2,12 mm. long (palm 1 mm., fingers 

 1,12 mm.). In the ova-bearing female from Stat. 273 these segments are 1,82 mm., 0,92 mm., 

 0,52 mm., 0,52 mm. and 0,88 mm. long, chela 2,12 mm. long (palm 0,96 mm., fingers 1,16 mm.). 

 The i st segment is hardly twice as long as the 2 nd , but in adult males a little more than twice 

 as long (de Man, 1. c. p. 756), in A. Hippothoë, however, this segment is comparatively longer; 

 in the specimens that were measured, the chela appears slightly longer than the three last 

 carpal segments taken together. 



Merus of 3 rd legs 4 — 4,5-times as long as wide in the middle, armed with a strong 

 acute tooth (de Man, 1. c. fig. 66). 



Both chelae of the first pair are but little hairy on their inner side and are not marked 

 with the small, blue spots that we observe on the chelae of A. edamensis and A. Hippothoë. 



The egg-bearing female from Balikpapan is 34 mm. long, longer than all the specimens 

 previously observed. The rostrum reaches to the distal fourth of the visible part of basal anten- 

 nular article; the rostral carina appears in a lateral view decidedly concave between the eyes 

 and is traceable, though inconspicuously, almost to the middle of the carapace. Carpocerite 

 and scale of scaphocerite as long as the antennular peduncle, not shorter; outer margin of the 



