1 65 



(in Ar. indicus the carpocerite is 3-times as long as thick). The telson resembles that of Ar. 

 dorsalis Stimps. ; in the male it is 4-times as long as the posterior margin is wide, the latter 

 not very prominent, outer angles acute, very short : proportion between the width at the base 

 and that of the posterior margin 2,3. The longer, inner spinules near the outer angles measure 

 one-third the width of the posterior margin and extend by half their length beyond the latter. 

 Spinules of the upper surface small, implanted close to the lateral margins ; those of the anterior 

 pair, that are 0,07 mm. long, Yis of the length of the telson, are placed, in the male, twice 

 as far from the base as from the distal end of the telson. In the outer uropod the distal 

 extremity of the outer margin is not curved outward, different from Ar. indicus. 



Chelipeds asymmetrical in the male, symmetrical in the female. The merus of the larger 

 (left) cheliped of the male is about twice as long as wide, the margins unarmed at apex. 

 Carpus almost as long as the merus, a little less high than long, the proportion being as 

 9:10; the lower surface is deeply hollowed out, in order to embrace the merus and this 

 concavity is bounded at the inner side by a crest that ends in an acute tooth ; the inner surface 

 is grooved, the groove runs parallel with the posterior margin and not far from it. Outer face 

 triangular as in Ar. indicus, but the lower margin is straight ; the distal margin is slightly 

 concave and a fine, impressed line runs from the middle of that margin toward the rounded, 

 distal extremity of the infero-external margin of the merus. Chelae turned outward, the fingers 

 placed horizontally, the dactylus at the outer side. The large chela which is as long as the 

 carapace, rostrum included, resembles, as regards its outer form, that oi Ar. indicus; the palm 

 is longer than high, the proportion being as 7:5, and a little longer than the fingers, measured 

 along their axis ; the lower (outer) face of the palm is slightly convex, the upper (inner) less so. 

 The concavity of the lower border of the chela is deeper than in Ar. indicus and the fingers 

 that are crossing one another, are more sharply acuminate. In Ar. indicus the dactylus is 

 unarmed and the immobile finger carries but one single tooth (H. Coutiere, Alpheidae Maid, 

 and Lace. Archip. 1905, Fig. 135^). In Ar. Iphianassa, however, the dactylus is armed with 

 one tooth, the immobile finger with two. Just in the middle the immobile finger is armed 

 with a strong tooth, which is directed obliquely forward and which is not acute, but 

 obliquely truncate and at the inner (upper) side even slightly excavate; between this tooth 

 and the articulation one observes another similar tooth, which is half as large and obtuse. 

 The dactylus is armed, just in the middle, with a tooth that is slightly larger than the 

 proximal, but much smaller than the distal tooth of the immobile finger; 

 this tooth, placed between the two of the immobile finger, is as long as broad and rounded. 



Merus and carpus of the small cheliped as in the large. The chela closely resembles 

 that of Ar. indicus Cout. The fingers, measured along their axis, appear a little longer than 

 the palm, which is i, 3-times as long as high, the proportion between the length and the height 

 of the chela being 2,8. Like in Ar. indictis, the dactylus is unarmed, while the cutting-edge of 

 the immobile finger is high and denticulate. Proportion between the length of both chelae 1,1, 

 proportion between the height of the palm of the large chela and that of the smaller 1,18. 



The chelipeds of the female resemble the smaller one of the male, but the high crest 

 on the lower side of the carpus is entire, arcuate, not ending in a tooth and the fingers, 



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SIBOOA-EXPEDITIE XXXIX ir'. 22 



