Clare Island Survey — Acarinida. 39 13 



H. glohosa (de Geer) ; but if the Irish specimens are correctly named, they 

 are much more closely related to H. conjecta Koenike ; and I should not be 

 surprised if they are really a variety of that species. 



( The eye-plates of two of these specimens, male (Plate I., fig. 10a) and 

 female (PI. I., fig. 105), from the Clare Island district are figured in the 

 present paper. It will be seen that they are very similar to the published 

 drawing of H. distincta above referred to. The fourth epimeron also agrees 

 in showing a somewhat broader inner end, outside of which there is a 

 narrow chitinous rim, which is also present on the hinder margin, as in 

 Koenike's figure (12, fig. 57). 



What especially leads me to believe that this form is a variety of conjecta 

 is the identity of the male genital area in the two forms. The specimen of 

 which the eye-plate is figured (PL I., fig. 10c) is a male, and the genital area 

 of this example agrees exactly with that of males showing the typical ribbon- 

 shaped eye-plate of H. conjecta. The length of the male eye-plate is about 

 ■82 mm. The skin is covered with cone-shaped papillae, which are sharply 

 pointed on some parts of the body. The palps of the male are remarkably 

 short and thick ; the length is about '66 mm. The mandible agrees in structure 

 with that of H. conjecta ; length about '972 mm. The genital area measures 

 •512 mm. in length by "587 mm. in breadth. 



This species has already been recorded from Lough Gill, Co. Sligo, and 

 Mr. Soar says it has been found in Lincolnshire (23). 



[Hydrarachna Thoni Piersig. (Plate I., fig. lla-b.) 



This species must be recorded with reserve; an immature form collected by 

 Mr. W. P. de V. Kane in a lake near Clifden very closely resembles Piersig's 

 figures and descriptions of this species. Unfortunately only the nymph-form 

 of H. Tlioni has been described. 



The characters of the species are based on the structure of the eye-plates, 

 the genital area, the fourth epimera, and the skin papillae. The eye-plate 

 (length about - 54 mm.) of the Irish specimen is very like that of H. globosa, 

 except that the lower half of the inner margin is not so deeply concave as 

 it is in that species ; this is, however, a variable character. The genital 

 plates are convex on their outer margin, and are shaped more as in the 

 nymph of H. scutata Piersig — see preceding remarks on the nymph of this 

 species. The third and fourth epimera agree almost exactly with Piersig's 

 drawings, the subcutaneous chitinous margins of the fourth pan being 

 well marked (PL I., fig. 11a). The skin papillae are long, and suggest 

 the teeth of a saw in their regular arrangement (PL I., fig. lib).] 



