SLENDER-LEGGED SPIDER-CRAB. 19 



two on each branchial region, the posterior being the 

 larger, and one on the genital region in a straight line 

 between the two larger ones on the branchial. The feet 

 are all very long and slender. The hands in the adult 

 male are considerably longer than the carapace ; the fingers 

 curved. The second pair of feet are three times the length 

 of the carapace. On the sternum, immediately in front of 

 the apex of the abdomen, when in its usual position applied 

 against the thorax, is a round or oval prominent and po- 

 lished tubercle, of a greyish-white colour. 



In the adult state this is considerably the largest of the 

 British species of Inachus. It is also then readily distin- 

 guished from the others, by the general form, as well as 

 by the extraordinary length of all the legs, and especially 

 by the form and length of the first pair. But in the 

 younger state all these characters are much less conspi- 

 cuous, and it might almost be mistaken for /. Dorynchus, 

 but for the remarkable character of the round polished 

 tubercle on the thorax, which somewhat resembles the 

 half of a pearl. This is peculiar to the male, and cannot 

 fail to strike us as offering a very obvious mark of relation 

 to the Mediterranean species /. Thora- 

 cicus, on the thorax of which there is 

 a very curious development of a similar 

 hard shelly substance, in the form of a 

 broad, three-lobed plate. This formation is peculiar to the 

 genus Inachus, and, as far as it is at present known, to 

 the two species in question. 



The InacJius leptocMrus is extremely rare. It was dis- 

 covered by the ill-fated Mr. Cranch on the western coast 

 of Devon, or Cornwall, and was afterwards taken by Mr. 

 Prideaux from a crab-pot in Bigbury Bay. In Mr. W. 



Thompson's " Additions to the Fauna of Ireland," is men- 



c 2 



