380 ME. E. I. POCOCK ON THE 



fourtli subserially arranged, the sides and lower surface of the 

 fourth and fifth coarsely and closely granular throughout, the 

 upper surface of the fifth also granular, smooth only in the 

 middle and at its anterior end; vesicle granular laterally and 

 below, distinctly denticulate on each side in front ; a distinct 

 tubercle beneath the aculeus. Upper surface of palpi normally 

 granular and costate ; manus large, wide and long, finely granu- 

 lar above, with granular costae, its width about half the length 

 of the movable digit, the length of the hand-back about two^ 

 thirds the length of this digit ; digits sinuate at the base, lobate 

 internally, and not in contact when closed, with about 12 rows 

 of denticles. 



JPectines with 17 teeth. 

 , Length 60 mm. ; length of carapace 6'3, of tail 41, vridth of 

 1st segment 3'2, of 5th 4, of vesicle 3, length of 3st 5-5, of 5th 

 7*5 ; length of brachium 7, width 2"2 ; length of " hand-back " 5, 

 width of hand 3'5, length of movable digit 7'5. 



Locality. San Domingo (Mus. Brit.) ; Porto Eico {Mus. 

 £erol.). 



The above description is taken from a single male example 

 from San Domingo, in the collection of the British Museum. 

 The female is unknow^n to me, but Dr. Karsch's description of 

 examples of this sex in the Berlin Museum from Porto Eico, 

 altbough unsatisfactory in many points, seems to apply to 

 individuals which differ from the one from San Domingo in 

 characters which by analogy are merely of sexual importance. 

 Thus in the female the manus is not wdder than the brachium, 

 with the movable digit only slightly lobate ; the pectines are 

 basally lobate, and the tail is shorter, its fifth segment being 

 only equal to the carapace in length. Moreover, Dr. Karsch 

 makes no mention of the gradual expansion of tail from the base 

 to the fifth segment. 



It may thus be seen that the sexual features of T. ohtusus ai*e 

 practically the same as those of T. americanus. Nevertheless 

 Prof. Kraepelin undoubtedly fell into error in believing the tw'O 

 species to be synonj'mous. Apart from the marked diflTerence 

 between them in size and colouring, T. americanus being con- 

 siderably larger and of a nearly uniform dark tint, the latter 

 species has a large spiniform tooth beneath the aculeus of the 

 caudal vesicle, and the intercarinal spaces of the tail not closely 

 and coarsely granular. 



