39 56 Proceedings of the Royal Irish Academy. 



The specimens from these localities are in the coleoptrate nymph stage. 

 with armed second legs as figured by Berlese (1, Fasc. lxix, n. -1), also by 

 Oudemans (73). 



Distribution. — A wide-spread form, ranging from Siberia to Italy. 



Gamasoides bispinosus sp. nov. (PL IV. fig. 6. a, b.) 



Closely allied to G. spinipes, with which species it agrees in general 

 structure, differs, however, in the armature of the second legs. 



Xympha coleoptrata. Male, length 539/t, breadth 341,u. Second legs 

 (lig. 6«). instead of the single knife-shaped spine present on the underside of 

 the femur in G. spinipes, this species is armed with two such spines ; patella 

 with a single strong spine placed on the distal margin of the segment ; tibia 

 unarmed ; tarsus with two spines, the terminal one is, however, closely 

 adpressed, so that it looks like a strong keel along the underside of the 

 segment. Epistome trispinous, side teeth strongly developed. The chelicerae 

 resemble those of G. spinipes, fixed chela with at least five distinct teeth ; 

 free chela with a very long proximal tooth, and two smaller ones between 

 this and the end of the segment (fig. 6^). 



Localities. — Found amongst moss near Lough Fenagh, Co. Mavo, in 

 October. I have also found it amongst moss sent from Poyntzpass, Co. 

 Armagh. 



Halolaelaps glabriusculus Berl. et Trouess. 



1875. Gamasus marinas Brady 19. p. 307. 1889. H. glabriuscidus 



Berlese et Trouessart 17, p. 2. 1890. Zercon marinus Moniez 52, p. 13. 

 1902. Parasitus marinus Oudemans 60, p. 281. 1906. If. glabriuscidus 



Berlese 13, p. 109. 



A few specimens, including the male and female, of this interesting 

 species were found under stones between tide-marks on the sea-shore at 

 Westport in July. 



The genus is remarkable for the structure of the ambulacra, and for the 

 fact that the second and third pairs of legs are armed with stout spines in 

 the male. There is also a short bristle-like spine on the underside of the 

 femur of the first pair of legs, and in the following species there are three 

 stout spines in this position. In common with certain other shore-frequenting 

 mites, the ambulacra are of peculiar structure. In the present species they 

 are armed with two pairs of plates, i.e., a pair of leaf-like central lobes, and 

 a pair of long acuminate lateral lobes. It is of interest to note that the 

 ambulacra of the first pair of legs which in the Ganiasidae are used as 

 tactile organs are less modified from the ordinary type than in the case of the 

 other pahs. 



