153 



between both extremities. The vaginiform merus, which is 2,73 mm. long, resembles that of 

 the cheliped of Ath. Djiboiitensis • it shows its greatest wiclth just before the proximal third, 

 this width being slightly more than one-third the length of the member, namely 1 ,05 mm. ; 

 the upper margin is straight from the distal extremity until to the posterior third and then 

 curves backward toward the ischium, like in Ath. Djiboutensis, the posterior margin appears 

 somewhat like a S, running in the middle parallel with the upper margin and the merus 

 distinctly more narrows toward the proximal extremity than toward the distal one, which is 

 slightly excavate. Carpus very short, almost globular. Chela a little longer than the merus, 

 appearing 3,01 mm. long when measured to the tip of the immobile finger and 3,29 mm., 

 when the dactylus is included ; palm ovoid, twice as long as high in the middle, the chela 

 appearing 3-times as long as high, when the dactylus is included. The concave, lower margin 

 of the immobile finger makes, at the inner side, a dist i net angle with the convex lower 

 border of the palm ; this angle, a little behind the articulation of the fingers, is more prominent 

 in the small chela than in the large. As in Ath. Djiboiitensis, the fingers are gaping, the 

 dactylus being strongly curved and somewhat longer than the immobile finger ; the proportion 

 between the length of the chela and that of the dactylus, measured in the direction of the 

 axis of the chela, is as 2,76 : 1, the proportion between the length of the chela and that of 

 the immobile finger as 3,7 : 1, the dactylus being one-third longer than the other finger when 

 measured in the direction of the axis of the chela. The immobile finger is armed with 

 a large, compressed, subacute tooth that extends to near the upturned tip; the 

 anterior margin of this tooth is arcuate, convex. The dactylus bears near the base a longitudinal 

 tooth or lobe, much smaller than the tooth of the index and tridentate, and one observes 

 three very small, conical teeth on the distal half of the finger, the first of which is a little 

 larp/er than the followinp- 



The ri^ht lep; resembles the described one, but it is a little smaller and the fingers 

 are shutting together. Ischium with 6 movable spinules, as in the other lég. The merus 

 shows the same shape, but it is smaller, the length being in proportion to that of the merus 

 of the right leg as 1 : 1 ,08. Chela also smaller, its length being in proportion to that of the 

 right as 1 : 1,2; it is also 3-times as long as high, but the fingers that are finely denticulate 

 along- their whole lencfth, shut close top; et her and measure about one-third the length 

 of the chela. Carpus as in the other leg. 



The specimen from Stat. 162 is considered to be the female of this species, with some 

 doubt, because it carries no eggs. In both chelae of the first pair the fingers are shutting 

 together, the chelae resembling the small chela of the male; the right leg is a little larger 

 than the left. The ischium of this leg bears eight spinules, three at the distal, one at the 

 proximal extremity and four on the margin itself. Merus w i d e r in proportion to its length 

 than that of the small cheliped of the male, the proportion between length and width being 

 2,3, in the small cheliped of the male, however, 2,6; carpus and chela as in the latter, the 

 proportion between the length of the merus and that of the chela is the same, but the 

 prominent angle at the inner side of the lower border appears distinctly as a small tubercle. 



Merus of second legs in the male 5,5-times as long as wide. Carpus 1,35-times as long 



