II \i,i!i';Kr — 77/6' Acariiin of i.hc Scuskorc. lln 



closer exaniiiiiiLioii iiinkcs it clear LliaL the jiart of the sternum in front of the 

 <;eiiital foranu^u is weakly chitinized, and is formed by a uniting and enlarge- 

 ment of the jugular plates. Tiie genital foramen lies in the thickly chitiuized 

 margin of the tiue sternal shield, where it is fused with the jugular area, so 

 tliat Llie position of the foramen is quite normal. With regard to the 

 armature of the male chelicerae, it seems to me that tiie chitinoiis swelling at 

 tlie outer side of each free chela represents the modified male appendages; it 

 is absent from tlie female. The position of the female foramen is rather further 

 back than i.s usual in the Gamasidae, but its position is really much as in 

 certain other genera, such as in Gamasellus. A more important point, which 

 is not referred to in the original description of Ehodacarus, is the presence 

 of asniall conical plate between the genital and sternal shields. It is placed 

 immediately in front of the genital shield, as it possibly represents the fused 

 paragynial jilates. 



Rhodacarus roseus, Oudms. 



A few specimens found between damp Hakes at the top of the Orange 

 hielien zone at Malahide are apparently identical with the typical form. 

 Lower down, in the intertidal area, it is replaced Ijy a vaiiety which is, I 

 Ijelieve, the same as the form recently described as a new species by 

 Hull (26). 



Var. pallidus Hull, (PI. XXI, fig. 1 a, b.) 



The original description is as follows : — " Translucent white, with the 

 appendages tinted with brown. Considerably larger than roseus. Epistome 

 with a simple acute tapei-ing process without terminal ijlume or basal teeth ; 

 otherwise resembling roseus. West Allendale, under deeply embedded stones 

 with rcrijnmasvs humutus. I have seen two males only " (26, p. 57). The 

 length of the male is given as 440yu. 



In the Irish specimens the measurements are : in the female (tig. 1 a), 

 length about 550/(, breadth, 22t)(u ; in the male, .518/1 and 230ji(, so that, as 

 well as being considerably larger, it is also relatively narrower than tlie type 

 form for wliicli Oudemans gives the following measurements : length of 

 female, i!)t)/t ; of male, oSo/j. The colour is white tinged with pink, lyrate 

 organs brown, and the nioulii parts of a deeper brown. Thc> legs are 

 decidedly longer ; those of the female are about 550/(, ooO/x, oOO/i, and 450/i 

 respectively. Tlie long median spine of the epistome is minutely spiculato 

 at its apo.K, and there are one or two pairs of small finely pointed teeth close 

 to the base; possibly the presence of these characters was overlookeil in ilie 

 original speeinieiis. The armature of the tarsi appear to diii'er in the se.vcs ; in 



