302 MR. G. S. BRADY ON BRITISH MARINE MITES. [Apr. 6, 
usually been detected creeping on the stems of seaweeds or zoophytes 
or on the sides of marine aquaria; and to catch them in this fashion 
has doubtless the great advantage of presenting the creatures alive, 
so that their motions and habits, as well as the anatomical details 
of such delicate organs as those of the mouth, which are of course 
in active operation during life, may be more readily observed. My 
own knowledge of the Mites however, is, derived almost entirely from 
the examination of dead specimens ; for though I have often found 
them living plentifully under stones and in the crevices of rocks on 
the sea-shore, the method of capture which I adopt has always killed 
them. The little animals are very active, running with great agility ; 
and as a sudden nip of the forceps would most likely mutilate them 
so much as to render them useless for examination, I have usually 
when collecting dropped a little spirit from a full camel’s hair 
pencil over the retreating speck and so brought its movements to a 
stand-still for a time sufficient to allow of his imprisonment: pos- 
sibly if put into sea-water at once he might in some cases recover 
the temporary shock of the spirit bath, inasmuch as I have seen one 
species (Pachygnathus seahami) retain its vitality even after an im- 
mersion of many hours in a pretty strong arsenical solution, and I 
have also noticed that two or three drops of proof spirit does not 
always suffice to arrest the movements of the Acari over stones or sea- 
weed. The great majority of my specimens, however, have been 
obtained from the washings of material dredged in depths of several 
fathoms, and have not been observed until after prolonged immersion 
(in spirit) and death. 
In some dredgings made off the coasts of Durham and Yorkshire, 
the number of individuals was very considerable, almost leading one 
to the belief that they must in favourable spots colonize the mud 
almost as thickly as their better-known relatives a decaying cheese. 
The only British naturalists who have written on the marine 
Mites are, so far as I know, Allman, Gosse, and Hodge. 
The first-named author described a species (Halarachne hali- 
chert) parasitic in the nostrils of a Seal. Mr. Gosse, in the ‘ Annals 
and Magazine of Natural History,’ described and figured, with his 
characteristic accuracy and fidelity, three species, Halacarus rhodo- 
stigma, H. ctenopus, and Pachygnathus notops. More recently Mr. 
Hodge named and described, in the ‘Transactions of the Tyneside 
Naturalists’ Field Club,’ species which he believed to be new, but 
some of which must, I fear, be considered spurious ; his species were 
Pachygnathus seahami and P. minutus, Leptognathus falcatus, 
Halacarus granulatus and H., oculatus. I have myself taken all 
these in greater numbers than fell to the lot of Mr. Hodge, and 
have likewise been able to examine the type specimens, which, with 
the rest of his collection, are now preserved in the Newcastle 
Museum. ‘The additions which I have been able to make in this 
paper are the following :—TZrombidium fucicolum, Pachygnathus 
sculptus, Gamasus marinus, and Cheyletus robertsoni. 
Mr. Gosse mentions that Fabricius has described two Norwegian 
marine mites, dearus zostere and A. fucorum; but these seem to 
