136 Proceedings of the Royal Physical Society. 
except where these are hollowed out by cavities containing air. They are 
not found wandering on stones taken from rock pools. 
On 16th July 1912 some of these mites were placed under water in 
glass vessels. They remained at the bottom, motionless except when touched. 
The peritreme tubes (Fig. 7, Pr.) had a silvery appearance by reflected light, 
indicating that they contained air. When taken out of the water these 
individuals became active and began to walk about immediately. 
Several specimens kept under water till 11 A.M. the next day were then 
found to be dead. On 23rd July a number of the mites were placed on a 
stone, surrounded and partly covered by salt water, in an earthenware dish. 
They confined their wanderings to the part of the stone not submerged. 
2 ; : 
i] 
ae : 
_ Sr 
Fie. 6. Halolelaps glabriusculus. Fie. 7. H. glabriusculus. 
(a) Outline of body of female in Enlarged drawing of a portion of 
dorsal view. ventral surface of female, showing 
(b) Enlarged drawing of anterior stigma, Sr., peritreme tube, Px., and 
margin of “upper lip” or epistome, the bases of second, third, and fourth 
Ev., from a male specimen, legs of left side, 2, 3, 4. 
On the following morning, some of them were found sheltering on the under 
surface of the stone where the water did not cover it. Others were walking 
on the top of the stone. One seemed to be feeding, but the food particle 
was lost in the transference of the mite to a watch-glass, and no identification 
could be made. The apparent range of probable food substances included 
Polyzoa (Lepralia and Schizoporella), Hydroids (Sertwlaria and Clava), minute 
Annelids, and Halacarids. 
It was noticed that the mites when walking on a wet surface of the stone 
stopped frequently and seemed to rub the water from their legs and palps. 
At 10 p.m. on 24th July, a female specimen was isolated and placed 
under water. It remained alive, though motionless, and only struggling in 
