ON BRITISH HYDEACHNIDS. 253^ 



Dr. Cooke mentions that Saville-Kent had detected nearly forty 

 British species. 



The first writer in Britain on water-mites was Dr. Johnston, 

 of Berwickshire, about 1849. The next would be Dr. George,, 

 of Kirton Lindsey, who did not begin until about 1881. So if 

 Mr. Saville-Kent had written about them at the time he was 

 collecting, he would have come between the two writers above 

 mentioned. 



Besides making a good collection of adult forms, Mr. Saville- 

 Kent had al=;o been very successful in breeding the larvae, many 

 of which were quite unknown in those days. But although he 

 did so well with the larvae, like the writers who came after him 

 he made but little progress with the parasitic stage, owing, no 

 doubt, to the conditions under which they were bred being quite 

 different to the ponds and rivers from which they were taken. 

 As far as we know, all water-mites pass the larval stage as 

 parasites ; but it is in only a few instances we know the host in 

 which they take up their abode. The life-history of these minute 

 forms of animal life is the most interesting part to the naturalist ; 

 but Nature gives up her secrets very slowly. We know very 

 little more now than Mr. Saville-Kent did at the time he was 

 collecting forty years ago. The life-history of only a very few 

 species is recorded, yet Ave have over a thousand known to 

 science. 



Slides. The medium used by Saville-Kent for mounting his 

 specimens, and his methods of killing, were given in the note 

 already referred to in Science Gossip for 1882. They were as 

 follows: "The adult mites may be killed instantaneously, with 

 their legs extended as in life, by momentary immersion in scald- 

 ing water ; and they should then be mounted in a cell of suitable 

 depth, in either camphor water or a weak solution of, say, one 

 of spirit to four or five of water. Specimens thus preserved by 

 the writer so long ago as fourteen years still retain llieir pristine 

 form and brilliancy ; the scarlets, browns, greens and yellows, 

 chiefly characteristic of this group, being as bright as on the 

 day on which they were mounted. Both the ova and hexapod 

 larvae may be preserved in the same simple medium." There are 

 nearly two hundred slides of Hydrachnids in the collection at 

 the Museum, nearly all mounted in fluid as just mentioned in 



