FOUR-HORNED SPIDER-CRAB. 25 



females, which in this, as in many other species, are less 

 active than the males. Their movements are extremely 

 slow and measured, and they are very timid, concealing 

 themselves under the fuci, and remaining for a time almost 

 motionless. But notwithstanding their timid and lazy 

 character, they seize the object of their anger by a sudden 

 and unexpected snap, and nip with great force, holding on 

 with extraordinary firmness and tenacity, although unable, 

 from the bluntness of their pincers, to inflict a wound. 

 The manner of their seizing any object, when from their 

 slow motion it is least expected, reminded me of the mode 

 in which 1 have seen the Otolicnus tardigradus seize a bird, 

 or other small living animal ; and any one who has seen 

 both, must, I think, be struck with the similarity. 



This species of Pisa formed the type of the genus Blas- 

 tns of Leach, who, however, afterwards reunited the two 

 forms, which certainly are not sufficiently distinct to war- 

 rant their separation. It would appear from the paucity 

 of observations which I have found of the occurrence of 

 this species, that it is not a common one ; or at least that 

 it is very local. Mr. Couch says in his " Cornish Fauna" 

 that it is not common in that county. Dr. Leach gives, 

 as its localities, " The Isle of Wight, Teignmouth, and 

 Brighton. 91 It is not mentioned by Mr. Hailstone in his 

 MS. Catalogue of Hastings Crustacea, which he obligingly 

 sent me, nor do I remember to have found it there. I 

 have taken many small specimens on the Dorsetshire Coast 

 by dredging, and, as I before observed, in very large num- 

 bers at Bognor. The only account of its occurrence as an 

 Irish species is, that " two examples exist in Mr. Ball's 



but there is no doubt that they actually grow upon them, and are attached by 

 roots. This is evident from the healthy state of the little plants, as well as from 

 the direction of their branches. 



