ARCHED-FRONTED SWlMMlNG-CRAB. 99 



the longest, and the second shorter ; the fifth pair fringed 

 with long hair ; the terminal joint lanceolate, very acute. 

 Abdomen in the male regularly triangular ; in the female 

 semi-ovate, slightly carinated, the terminal articulation 

 triangular. The colour of this species is a dull blackish- 

 brown above, paler beneath, and with a tinge of red ; the 

 legs paler than the body. 



The habits of this species are very similar to those of 

 the other species of the genus as far as they have hitherto 

 been observed. They are active, bold, swimming with agi- 

 lity, and seizing with great sharpness, and pinching severely 

 with their acute claws. They are gregarious, like most of 

 their congeners ; and I found them extremely abundant 

 at Bognor, where they constantly infest the prawn-pots 

 and, as the fishermen believe, keep the prawns from the bait. 



I believe this species will prove, upon further observa- 

 tion, to be more generally distributed than has hitherto 

 been supposed. Dr. Leach giVes the more northern coasts 

 of England as its usual habitat ; I have dredged it in 

 Poole Harbour, and in the neighbouring bays of Studland 

 and Swanage, and plentifully at Bognor. ^Ir. Eyton sent 

 me specimens from the Welsh coast. Mr. Couch does 

 not, however, give it a place in his " Cornish Fauna ;" nor 

 does it occur in the late Mr. Hailstone''s MS. notes of 

 Crustacea taken at Hastings. In Ireland, Mr. W. Thomp- 

 son has taken it " when dredging in deep water in the 

 louofhs of Stranofford and Belfast ;" and he adds, " it was 

 procured by our party when dredging in Killery and 

 Roundstone Bays on the Western coast." Mr. Ball also 

 found it cast on shore at Portmarnock. 



I have never found the variety named by Leach P. 

 emarginatus. Of the hundreds which I have taken, all 



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