Halbkut — The Acnrina of the Seashore. 119 



Gamasus coleoptratorum L. 

 The female of this coinmoii Eiiropcaa species occunod under stones 

 resting on sand, gravel, and shells in the Orange Lichen zone at Malaiiide, 

 June, 1916. The nymph was also found, commonly under decaying refuse 

 lying on the rocks in the same zone, May, 1918, and on Westport shore in 

 September. 



Gamasus immanis Berl. 



1903 Berlese 7b, p. 262. 1900 Berlese 11. p. 179. 1915 Halbert 25, p. 50. 

 1918 Hull 26, p. 85. 1914 King 27, p. 129. 



This fine acarid, the largest of our native Gamasidae, was first recorded 

 as a British .species by King, who has publisiied some interesting observations 

 on its life-history (27). Subsequently I met witli it on the coasts of Dublin, 

 Mayo, and Cork (25) under stones, amongst shingle, and in decaying seaweeds 

 at high-water mark. It has also been found at Ardfry under limestone 

 boulders resting on damp sandy mud in the Orange Lichen zone, June, 1916. 



Gamasus Trouessarti Berl. 



1S89 Gamasus tludassinv.s Berl. et Trouess. 20. 1889 G. fucoinim var. 

 \i 38, p. 156. 1S92 G. Trmicssarti Berlese 3, p. 67. 1915 Halbert 25, p. 51. 

 1918 Hull 26, p. 85. 



An abundant and characteristic shore species, occurring in a variety of 

 habitats, from the Orange Lichen down to the Serratus zone, as at Malahide 

 and Ardfry. On the lower part of the shore it occurs chietiy in crevices and 

 rock fissures, and under stones embedded in mud. It is often abundant 

 under decaying seaweed at high-water mark, and I have found the adults 

 and uyniphs in the .'iand, i;ravel, and shell association, and in estuaries on 

 the Dulilin coast. 



Gamasus crassipes L. \ai. longicornis Berl. 



Lender stones and decaying seaweeds at Ardfry, June. A common and 

 widely distributed form, possibly not a regular inhabitant of the intertidal 

 shore. 



Gamasoides spinipes (C. L. Kocii)- 



1844 Gamasxis spinipes C. L. Koch 28, Fasc. 39, fig. 18. 1885 

 G. brachiosus G. Can. 23, p. 79. 1890 Poecilocheinis spinijics Oudemans 44, 

 p. 134. 1892 P. spinipes Berlese 2, Fasc. i,xi.\. n. 4. 1906 Gamasoides 

 ynnipes Berlese 11, p. 288. 



These are some of the more important references to this peculiar form, 

 which is known only in the nympha cokoptrata stage, and it may yet prove 



