Mr. W. Thompson on the Crustacea of Ireland, 275 



R. Ball at the South Islands of Arran*, as well as at Youghal and 

 Dublin. The motions of this crab are slow, though its light body- 

 borne on such long legs would be popularly believed to indicate con- 

 siderable powers of locomotion. The editor of the octavo edition of 

 Pennant's ' British Zoology' (1812) remarks, that this crab " invests 

 itself occasionally in leaves of fuci to ensnare its prey ;" and Dr. 

 Leach states that " it has been observed by Dr. Macculloch to be 

 sometimes covered by fragments of a species of the Linnsean genus 

 Fucus, which are attached to its body and legs." The first state- 

 ment seems to me fanciful. The presence of fragments of fuci, &c. 

 I should rather attribute to the spinous body, and the bristly arms 

 and legs of great length intercepting adventitious substances, which 

 in floating through the water come in contact with them, and (as 

 Mr. R. Ball reminds me) are further retained there by a viscid slime 

 covering the animal. Many marine productions, however, both of a 

 vegetable and animal nature, have their birth, and grow to beauty on 

 the shell of this as well as other species of our native Crustacea — 

 corallines, sponges, zoophytes, alga?, &c. may thus be found. Balani 

 occasionally cover the entire upper surface of the body of the crab. 



Aug. 22, 1840. — On opening a thornback (Raia clavata), about 

 20 inches in length, caught in Belfast bay, I found its stomach en- 

 tirely filled with Macropodia phalangium. 



Achceus Cranchii, Leach, Mai. pi. 22 c ; Edw. Crust, t. i. p. 281. 



In the collection of Crustacea formed by Mr. J. V. Thompson, and 

 now in the possession of the Royal College of Surgeons, Dublin, is a 

 native specimen of this crab, which we may presume was obtained 

 on the southern coast. 



Inachus Dorsettensis, Leach, Mai. pi. 22. f. 1 — 6 ; Desm. p. 52. pi. 



24. f. 1. 

 I. scorpio, Edw. Crust, t. i. p. 288. 

 Cancer Dorsettensis, Penn. vol. iv. p. 12. pi. 10. f. 1. 



This species is stated by Mr. J. V. Thompson to be common in 

 the harbour of Cove. Ent. Mag. vol. iii. p. 371. It is pretty com- 

 monly brought up from deep water in the dredge in the loughs of 

 Strangford and Belfast, but in much smaller quantity than Macro- 

 podia phalangium. Under similar circumstances it has been procured 

 by us on the western coast. Mr. R. Ball finds it in Dublin bay. All 

 the examples of this crab which I have taken were invested with 

 sponge, which generally covers over the body, arms, and legs ; algae 

 and zoophytes likewise spring from it. In this extraneous matter 

 some of the smaller Crustacea find shelter, and, together with the 

 other objects, render the capture of the Inachus Dorsettensis interest- 

 ing far beyond the acquisition of itself. 



Capt. Beechey, R.N. of H.M.S. Lucifer, brought up a specimen 

 of this Inachus alive in the dredge from a depth of about 140 fathoms 

 off the Mull of Galloway. See ' Annals' for Sept. last, p. 21. 



* On different parts of the western coast it was dredged by us in 1810. 



T'2 



