CHARLES D. SOAR ON HYDRACARINA. 



the malpigMan vessel being liglit yellow. The epimera and 

 appendages are a greenish blue, in some specimens quite blue^ 

 The eyes are about 0-1 mm. apart, of a bright- red colour. 



The genital area is about 0-13 mm. long, about half of which 

 lies within the bay formed by the posterior margin of the epimeral 

 plate. This bay is not so wide on the outside margin as in the 

 preceding species, the two sides being nearly parallel (PI. 1, 

 fig. 16). The anterior part of the epimera does not project 

 beyond the frontal margin. One striking point which difier- 

 entiates this species from 0. ovalis is that the anus is placed in 

 the line connecting the two anal glands. 



Male. — The male is about 0-65 mm. long, and less in width 

 than the female in proportion to its length. The genital plates 

 project about one-third beyond the end of the epimera, of which 

 the bay in the posterior margin is about 0-1 mm. deep, and as in 

 the female the sides are nearly parallel. 



Cumberland, Oban, Surrey. 



Description of Figures, Plate 1, 



Fig. 16. Ventral surface, ?. 

 ,, 17. One of the acetabula in outline showing the rounded 



ends. Compare this with fig. 7 (0. plantaris), 

 ,, 18. Palp of female, lateral view of right palp. 



Journ. Quekett Microscopical Club, Ser, 2, Vol. XIV., No. 84, April 1919. 



