Clare Island Survey — Acarinida. 39 65 



Pachylaelaps longisetis sp. nov. (PL V, fig. \2a-d.) 



Compared with P. pectinifer, the present species is remarkable for its 

 very regular oval shape, the much longer hair vestiture of the body, the 

 rather narrow anal plate, and other details of its structure, notably of the 

 peritreme. 



Female (fig. 12a).— The length is 793,u, breadth 460/x. Shape a long 

 oval, shoulders scarcely at all indicated. Dorsal surface smooth, with very 

 long, scattered hairs, consisting of a regular marginal row, and at least two 

 double inner rows. Ventral surface with the usual plate armature, sternal 

 shield with four pairs of long hairs; metapodial shield extending backwards in 

 a sharply pointed process. The peritreme is bent sharply inwards between the 

 aeetabula of the second and third legs, much as in P. furcifer Oudms. ; 

 stigmata small, placed opposite the front margin of the last coxae. Genito- 

 ventral plate of the usual shape, slightly flattened on the hinder margin. 

 Anal plate as long as it is broad, differing in this respect from the allied 

 species. The hair vestiture of the ventral surface is also very long ; apart 

 from marginal hairs, there are at least six long curved hairs on each side of 

 the anal plate, 



Oapitulum short and broad; epistomal process (fig. 125) very broad and 

 only slightly constricted, terminal comb with nine or ten uniform teeth. 

 Seen from the side the chelicerae (fig. 12c) are short and stout, the free 

 chela has too strong widely separated teeth ; the fixed chela has one tooth 

 and the sinuate membranous flap behind this tooth is very finely striated 

 at the margin. Maxillary lobes long and slender. Palps small, much as in 

 P. pectinifer, ventral face of second segment with two stout bristles. 

 Tritosternum feebly developed, filaments with fine, closely set pectinations. 



Legs rather slender; the lengths are approximately 561/x, 495^, 363/y, and 

 517;u. Femur of second pair with only a slight distal prominence. There 

 is a small conical papilla on the dorsal side of the trochanter. Hair and 

 tarsal spine armature much as in P. pectinifer; except that the hairs are 

 longer in the present species (fig. 12a"). 



Locality. — The female of this species occurred in a decayed tree trunk at 

 Glendarary, Achill Island, during November. 



Hydrogamasus Giardi (Berl. et Trouess.). 



This is evidently a true tide-mark species. I have found it commonly on 

 limestone rocks, exposed by the tide, on the seashore near Malahide, Co. 

 Dublin. 



