Mr. W. Thompson on the Crustacea of Ireland. 283 



Portunus pusillus, Leach, Mai. pi. 9. f. 5 — 8; Edw. Crust, t. i. p. 

 444. 



Generally inhabits deep water. It is ordinarily taken by us when 

 dredging in the loughs of Strangford and Belfast ; at the Killeries in 

 Connemara it has similarly occurred as well as in Dublin bay. In 

 the south too, it has been taken by Mr. J. V. Thompson in the har- 

 bour of Cove — see note on P. marmoreus, p. 282. I have several times 

 found it in the stomachs of fishes, in one instance in a Trigla Gur- 

 nardus, taken in the open sea off Down. 



At Compton, in the Isle of Wight, I procured several of this spe- 

 cies thrown by the waves upon the beach. 



Portunus arcuatus, Leach, Mai. pi. 7. f. 5 & 6. 

 P. Rondeletii, Edw. Crust, t. i. p. 444. 



Has been taken occasionally by us when dredging in deep water 

 in the loughs of Strangford and Belfast ; and has been found cast 

 ashore at Portmarnock by Mr. R. Ball. It was procured by our party 

 in the summer of 1840 when dredging in Killery and Roundstone 

 bays on the western coast. Specimens are in Mr. J. V. Thompson's 

 collection, and it may be presumed, from Cork. All the examples of 

 this species which have occurred to myself were taken in the dredge 

 excepting on one occasion (Oct. 1) at Killinchy, on the shore of 

 Strangford lough, when looking to the refuse in a number of small 

 boats which had been employed the night before in herring fishing, 

 I found in every one of them several of these crabs which had been 

 brought up in the nets, and not one of any other species. 



Leach remarks that '1 P. arcuatus differs from P. emarginatus only 

 in the form of the anterior part of the shell, and may be no more 

 than a variety of that species." M. Edwards considers them the same. 

 All the specimens preserved (about thirty) from the different loca- 

 lities mentioned, — and there is about an equal number of both 

 sexes ranging from a very small size up to that of Leach's figure 

 of P. emarginatus, — have the anterior part of the shell correspond- 

 ing to that of P. arcuatus, or in other words, arched : — " fronte ar- 

 cuato integro" is Leach's description of it. 



Pinnotheres pisum, Leach, Mai. pi. 14. f. 1 — 3, female ; Desm. p. 11 8. 



pi. 11. f. 3. 

 P. varians, Leach, Mai. pi. 14. f. 9 — 11, male. 

 P. Latreillii, Leach, Mai. pi. 14. f. 7 & 8, young female*. 

 P. pisum, Edw. Crust, t. ii. p. 31. 

 Cancer pisum, Penn. vol. iv. p. 3. pi. 1. f. 1, female. 

 C. minutus, Penn. vol. iv. p. 5. pi. 1. f. 2, male. 



Temple ton has noticed this species as " dredged up in Belfast 



* These synonyms are brought together agreeably to the views of M. Ed- 

 wards, who further observes that P. Cranchii t Leach, seems not specifically 

 different from P. pisum, and that P. Montagui, Leach, is perhaps a variety 

 of the same. With M. Edwards I agree in the opinion that P. Cranchii is 

 not distinct from P. pisum ; but P. Montagui as described and figured by 

 Leach rather seems to me a different species. About twenty male sped- 



