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
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