114 Pi-oceedmgs of the Royal Irish Acadcmij. 



there is a layer of damp sandy mud : occasionally seen running on ihe rocks 

 at low tides. I have found adult and late nymplial forms well below tide 

 marks in the Vesiculosus and Serratus zones ; on Uie other liand, the early 

 nymphal form (protonymph) occurs commonly on the upper parts of the 

 intertidal area, usually in the Pelvetia zone. At Ardfry it. occurred under 

 stones resting on mud, June. 



First described by Tietze (23) as an unnamed species of ffrtma^?«, his figures 

 leave no doubt that the species dealt with is the present one; subscipu ntly 

 described by lieilese from specimens collected by Trouessart on the coast 

 at Fiuislerro. Both sexes, tlie prolonyniph and the iii/nipka colcopfratu, arc 

 described in 25. 



Gamasolaelaps excisus {L. Koch). 



1879 .Swiiw excistis L. Koch 22, p. 122. 1903 Cyrtolaclaps (?) auraniiaciis 

 Berlcse 7a, p. 241. 1906 Gtimasohiclups aumntiacus Berlese 11, p. 101. 

 1915 Halbcrt 25, p. 58. 191S Hull 26, p. 77. 



The ntfmp/ia ailtoptrata form of this species occurred on the Mayo Coast 

 at Westport and Muhanny in July and September. The adult female was 

 found under stones in a brackish jdace, a little above high-water mark, at 

 Howth ill Septeiiil)er (25). Tlie species iias not been found since in Ireland, 

 but I believe the localities are such as would correspond to the Orange Lichen 

 zone. 



There can scarcely be any doubt that this is the mite described and figured 

 by L. Kocii as SeiiLs excisufi (29 : therefore the species is recorded as above. 



Rhodacarus Oudms. 



In his " New List of Dutch Acari " (43. p. 48) Oudenians described a very 

 interesting acarid — liliodacarus — an<l established a new sub-family for its 

 reception. His chief reasons for doing so are that the genital aperture of the 

 mole is situate<l mi tlie sternal shield instead of on its front margin, and the 

 chelicerae are witiiout appendages in both sexes. He also coninienls on the 

 position and structure of the female genital foramen, and the division of the 

 botly into two distinct regions, "a true thorax and a true abdomen." 



The occurrence of IlIuHUuariu roseus in Ireland has already been recorded 

 (26, p. 81), and I iiave recently found a varietal form of it living in rock- 

 flssnres on the seashore at Malahide. Dr. Uudeinans found the type in 

 HidlaiKl amongst decaying leaves, and the Irish si>eciiiieiis occurred in a 

 similar habif,at in marshy places at Glendalough and in the Tolka valley, 

 near Dublin. 



In the male the geniual foramen (I'l. XXI, lig. lb) would at fir.st sight 

 appear placed at some distance from the front margin of the st<irnuiii, but a 



