150 ^^6 Philippine Journal of Science lais 



the merus of the fourth leg, and 3 movable spines on the merus 

 of the right fifth leg. The conditions are similar for the left legs, 

 except that there are only 3 spines on the merus of the fourth leg 

 (fig. 1, n, 0, p) . 



Specimen 6 (museum No. 1371) is 34 millimeters long and 

 has 3 teeth on the lower border of the rostrum. There are 2 

 movable spines on the merus of the right third leg, 4 on the merus 

 of the right fourth leg, and 3 on the corresponding segment of 

 the fifth leg. The conditions are similar for the feft legs. 



Our smallest individual, specimen 7 (museum No. 1377), is 

 25 millimeters long and has 4 teeth on the lower border of the 

 rostrum. There are 3 movable teeth on the merus of the right 

 third leg, 4 movable teeth on the merus of the right fourth leg, 

 and 3 movable teeth on the merus of the right fifth leg. The 

 conditions for the left legs are similar. 



The third leg is conspicuously larger in diameter than the rest 

 of the legs in specimen 1, but this difl^erence becomes gradually 

 less marked in Nos. 2, 3, and 4, and it is hardly noticeable in the 

 smaller specimens. These 7 specimens show a reduction in the 

 number of spines on the merus of the fifth leg from 3 movable 

 spines in specimen 7 to 1 or 2 movable spines in specimen 1 ; on 

 the merus of the fourth leg they show a reduction from 4 movable 

 spines in specimen 7 to 3 movable spines in specimen 3, to 2 

 movable spines in specimen 2, and to 1 movable spine in spec- 

 imen X; on the merus of the third leg they show a reduction 

 from 3 movable spines in specimen 7 to 2 movable spines in 

 specimen 6, to 2 movable spines (the most distal only slightly 

 so) and the rudiment of the heavy spine between the two in 

 specimen 4, to 1 slightly movable spine and 1 immovable spine 

 in specimen 3, and to 1 immovable spine in specimens 1 and 2. 

 It is probable that all of these specimens belong to the same 

 species; that with increasing age or degree of maturity there 

 is a reduction of the number of spines on the meri of the third, 

 fourth, and fifth legs; that on the approach of maturity in 

 the male the heavy spine begins to make its appearance (specimen 

 4) on the merus of the third leg; that during the succeeding 

 molts the heavy spine becomes well developed and the slender 

 movable spine posterior to the heavy spine disappears (specimen 

 3) ; and finally, that the slender spine anterior to the heavy spine 

 ceases to exist (specimens 1 and 2). 



I am very much inclined to believe that Atya spinipes New- 

 port,'' described from a specimen found in the Philippines, is a 



'Ann. & Mag. Nat. Hist. (1847), 19, 159. 



