THE GENETiA AND SPECIES OF SYWrHYLA. 53 



in various respects. In the largest specimen the last pair 

 (fig. 2 e) is exceedingly thick, the metatarsus being only one 

 half longer than deep, and the tarsus, Avhich is strongly 

 "widened towards the base, slightly more than three times 

 longer than deep; the tibia has on the upper side some short 

 setse, and a distal, very thick seta which is slightly shorter 

 than the depth of the metatarsus; the metatarsus with four 

 dorsal setse, the second of which is rather long, longer than 

 the first and the third, Avhile the fourth is only a little 

 shorter than the long seta on the tibia; the tarsus with five 

 dorsal sctne, the first and the fifth short, the three others 

 rather long. In another adult specimen the twelfth pair 

 (fig. 2 g) is considerably more slender, the metatarsus being 

 twice as long as deep, and the tarsus almost four times 

 longer than deep ; the distal seta on the tibia is somewhat 

 shorter, the metatarsus with four dorsal setse, and three of 

 these as in the large specimen, while the fourth is even 

 somewhat longer than the depth of the joint; the tarsus 

 with four setffi, the second and third rather long. In the 

 large specimen the ninth pair of legs are about as robust as 

 the twelfth pair of the other specimen, and the tenth and 

 eleventh pairs form transition stages to the thick twelfth 

 pair described above. (In a small and immature specimen 

 with eleven pairs of legs the eleventh pair [fig. 2 k'] are 

 rather aberrant, the metatarsus being only one third longer 

 than deep, and the tarsus, which is slender at the end, is 

 proximaliy very broad, and so deep that it is not three times 

 longer than deep ; the setae can be seen on the figure. The 

 posterior pairs of legs decrease gradually in thickness from 

 behind forward, so that the eighth pair are slender. It can 

 be asserted that the specimen does not present any other 

 difference from the typical form.) The anterior claw (fig. 

 2/) of the last pair of legs always of medium length, mode- 

 rately robust and somewhat curved; the posterior claw is a 

 little more slender, and about two thirds as long as the 

 other; the front seta is rather long, but proportionately 

 slender. The exopods are rather long. The first pair of 



