ARTHROPOD FAUNA OF THE WEST IlfDIES. 383 



Pectines not reacliiiig the end of the coxae, furni:shed. with 

 19-20 teeth ; the proximal iutermediate lamella dilated. 



(S . Tail very long, about 1\ times the length of the carapace, 

 the fifth segment very slightly wider than the first ; the " manus " 

 larger than in $ , a little longer and wider ; the length of the 

 '■ hand-back " about f the length of the movable digit ; the lobe 

 and excavation a little bigger than in the $ , but the digits not 

 noticeably sinuate as in T. antillanus. 



Pectines nearly reaching the end of the coxae, furnished with 

 21-22 teeth; the proximal intermediate lamella not expanded. 



Length of $ 56 mm., of carapace 6, of tail 35 ; length of S 

 63, of carapace 55, of tail 41. 



Locality. St. Vincent {IL. H. Smith). 



8. TiTYUs Smithii, sp. n. (PI. XXX. figs. 9-9 a.) 

 IN'early allied to T. pictus. The two species may be contrasted 

 as follows : — 



T. pictus. 



mm. 



Total length 63-5 



Length of cai-apace b'i'y 



tail 40-5 



Width of 1st caudal segm.... 2'4 

 5th „ „ ... 2-5 



„ poison-vesicle 2-2 



Height of „ „ 2-3 



Length of vesicle 4 



,, aculeus 2'9 



Total length 54 



Length of carapace 6"8 



tail 35 



Width of 1st caudal segin 25 



5th „ „ ... 2-3 

 „ poisuii-vcsic le 2'1 



T. Smithii. 



mm. 



Total length 62-5 



Length of carapace 58 



tail 40-5 



Width of 1st caudal segm. ... •3-2 

 5th „ „ ... 3-5 



„ poison-vesicle 2 



Height of „ „ 2 



Length of vesii'le 3 5 



,, aculeus. 3'2 



Total length 59 



Length of carapace 5"3 



tail 35-5 



Width of 1st caudal segiu. ... 3"2 

 5th „ „ ... 3 8 

 „ poison-vesicle 2 



The above dimensions show at a glance the chief differential 

 characters of T. SmitTiii. The tail is much stouter, while the 

 vesicle is much smaller, being narrower, lower, shorter, and fur- 

 nished with a longer aculeus. In colouring the two species are 

 almost alike ; but on the whole the fuscous markings of T. pictus 

 are more conspicuous, the general aspect of the whole animal 

 being more mottled. In development of keels and granulation 

 tiiere is no observable difference between the two ; the hands, 

 however, of T. pictus are a little slenderer. 



The specimens of which the measurements are given in the 

 above Table were selected because they agreed best with the 

 largest examples of T. pictus. The apparent discrepancy in the 



