IÖ2 



Merus of second legs very slender, io-times as long as wide, curved a little. Carpus 

 almost one-third (1,28-times) longer than the merus, also very slender; first segment 8-times as 

 long as thick at the distal end, one-ninth shorter than the sum of the four following ; second 

 segment three-tenths of the first, fifth one-third longer than the second and just as long as 

 the third and the fourth combined, the fourth a little longer than the third. Chela i 3 / :5 -times 

 as long as the fifth segment and 3,5-times as long as broad ; fingers nearly as long as the 

 palm. The measurements, indeed, of the merus, of the carpal segments and of the chela are 

 respectively : 1,85 mm.; 1,12 mm., 0,34 mm., 0,21 mm., 0,25 mm., and 0,46 mm. ; 0,77 mm. 



Ischium of third legs with a movable spine on the proximal half of the posterior margin 

 and with another just before it on the outer surface. Relative dimensions of the third legs : 

 merus 1,57; carpus i; propodus 0,91. Merus 4,45-times as long as wide, its greatest width at 

 the proximal third; carpus unarmed, slender, 5,7-times as long as thick; propodus a little 

 shorter than the carpus, also 5,7-times as long as wide, showing its greatest width at the 

 proximal third ; the propodus bears 3 small and feeble spinules on the posterior margin and 

 2 at the far end one of which is longer than the preceding. Dactylus simple, short, measuring 

 one-fourth of the propodus ; its form is rather stout, the dactylus being only 3-times as long 

 as thick at its base. Measurements of the fifth pair: merus 1,2; carpus i; propodus 1,3. 

 Merus 5-times as long as wide, carpus 6-times, both joints, like also the merus, unarmed; 

 propodus 10-times as long as wide, longer than the merus, with the usual transverse tufts of 

 setae. The dactylus resembles that of the third pair, but measures one-sixth of the propodus. 



Length 13,5 mm. 



Arete Stimps. 



Besides two specimens of Arete dorsalis Stimps., one new species and one variety, also 

 new, of Ar. Afaruteensis Cout. were collected by this expedition. The two specimens of Ar. 

 dorsalis do not fully agree with the specimen which by Professor Coutière was also referred to 

 this species (Alpheidae Mald. and Lacc. Archip. 1905, p. 866 Y ) : in the specimen from Goidu Atoll 

 the carpocerite appears much longer than the scaphocerite and even slightly surpasses the 

 antennular peduncle. According to Stimpson, however, the scaphocerite is not shorter than the 

 antennal peduncle ("antennarum appendix brevis, lata, pedunculum vix superans"), just 

 as in the specimens captured by the "Siboga". I don't venture, however, to regard Coutière's 

 species as different, because in the "Siboga" specimens both chelipeds are missing. The new 

 variety of Ar. Maruteensis only differs by subordinate characters. The new species, finally, 

 Ar. Iphianassa, approaches closely to Ar. indicus Cout., but the armature of the fingers of 

 the larger chela in the male is different and there are still more differences. 



A re-examination of the young specimen from Amboina preserved in the Museum of 

 Göttingen, which specimen was referred by me in 1888 (Archiv f. Naturg. 53. Jahrg. p. 527) 

 to Ar. dorsalis, proved it to belong to a new species for which the name of Ar. amboinensis 



1) I must draw the attention to some typographical errors in this description. The merus of the third legs of Ar. dorsalis is 

 said to be 3,7-times as long as wide (p. 867) and that of Ar. Maruteensis 3,8-times (p. 868) : in the later description of the latter species 

 (in: Buil. Muséum Paris 1905, p. 22), however, these numbers are respectively 4,6 and 2,75: here apparently correct. 



3° 



