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



Fig. 16. Interlacing double spirals, leaving spaces which afterwards become 

 dots. (After Barry.) 



Fig. 17. Same in a more advanced stage. (Id. loc. cit.) 



Fig. 18. Dotted duct thus perfected. (Barry, loc. cit.) 



Fig. 19. Fibres from T. latifolia bent and thickened, in an advanced stage. 



Fig. 20. Dotted vessel from Arundo Donax, the black lines formed by ad- 

 herent portions of vegetable matter which filled up the spaces se- 

 parating the surrounding cells and vessels. 



Fig. 21. Dotted duct from Sambucus nigra. 



Fig. 22. Transverse section of dotted tube in Aspidium Filix mas, showing 

 the rows of dots corresponding to projecting portions of surround- 

 ing cells. 



XVII. — The Crustacea of Ireland. By Wm. Thompson, Esq., 

 Vice-Pres. Nat. Hist. Society of Belfast. 



[Continued from vol. x. p. 287.] 



Order Decapoda. 



2nd Section. Decapoda Anomoura. 



Lithodes Maia, Leach, Mai. pi. 34. 



L. arctica, Edw. Crust, t. ii. p. 186; Desm. Consid. Crust, p. 160. 



pi. 25. 

 Horrid Crab, Penn. Brit. Zool. vol. iv. p. 6. pi. 8. f. 14, edition 1812. 

 Templeton says of this species — " Found on the coast of the county 

 Wexford : a specimen thence is in Trinity College Museum [Dublin] . 

 It is called by the people craban." 



I have not seen any Irish example of this crab, but am indebted 

 to Dr. Wylie of Ballantrae, Ayrshire, for a very fine specimen which 

 was taken in a herring-net there in the summer of 1 838, in water from 

 twenty to thirty fathoms in depth. It was brought to Dr. Wylie by 

 the fishermen as a species which they had never before met with. 



Pagurus Bernhardus, Edw. Crust, t. ii. p. 215 ; Penn. vol. iv. p. 30. 



pi. 18; Desm. p. 178. pi. 30. f. 2. 

 P. streblonyx, Leach, Mai. pi. 26. f. 1 — 4. 



Hermit-crabs of this species are very common in univalve shells 

 around the coast of Ireland. Leach mentions their •' first occupying 

 the shells of the common periwinkle ortrochus" (Art. Crustaceology 

 in Edin. Encyclop.) ; but some examples in my collection are much 

 smaller than those contained in the species just named. They are 

 in the Littorina retusa, Turritella terebra, and Nasa macula — univalves 

 from this size up to that of the largest Buccina are commonly inha- 

 bited by the P. Bernhardus : a specimen of this crab from the coast 

 of Down, in my collection, is 6 \ inches in length. Samouelle speaks 

 of the shell occupied by the Pagurus being " destined to preserve the 

 body from injury, and to guard them from the attacks of fishes, 

 which would otherwise devour them." Entom. Compend. p. 92. In 

 this latter respect the shells are of little service, as I have remarked 

 Paguri very commonly in the stomachs of various species of fishes, 

 but especially in the omnivorous and voracious cod : all the mo- 

 derate-sized and large hermit-crabs which have thus occurred to me 



