1875.] MR. G.S. BRADY ON BRITISH MARINE MITES, 303 
be distinct from any thing at present known to us in Britain. The 
same author says also, on the authority of M. Paul Gervais, that M. 
Dujardin “had described a marine Oribates in the ‘Journ. de 
Institut,’ for 1842,” but he was unable to verify the quotation. 
Besides these, the only marine Acari of which I have found notices 
are Thalassarachna verrillii, described by Dr. A. S. Packard in the 
“American Journal of Science and Arts,’ vol. i. 1871, and Ponta- 
rachna punctulatum, Philippi, in Wiegmann’s ‘Archiv,’ vol. vi. p. 191, 
1840, pl. iv. figs. 4, 5. 
I have not thought it necessary to reproduce in extenso the 
descriptions of previously known species, but have contented myself 
with noting their more important characters, combining my own 
observations with those of prior authors. 
Class ARACHNIDA. 
Order AcCARINA. 
Fam. TROMBIDIADZ. 
Genus Tromsinivum, Fabr. 
TromBIDIUM (?) FUCICOLUM, nov. sp. 
Length ;'> of an inch: colour very dark brown, opaque ; body 
tumid, tapered and pointed in front, broadly rounded behind, produced 
laterally into two angular promontories at the origins of the first 
and second pairs of legs; surface corrugated. Mandibles consisting 
of two triangular plates (?) opposing each other in the median line ; 
palps small, obtuse, 4- or 5-jointed, the penultimate joint bearing a 
small appendage something like an obsolescent unguis. Thighs not 
distant, all the pairs of legs having origin toward the front of the 
body. Legs 5-jointed, stout, opaque ; second and fourth joints much 
the longest, first and third shortest ; last joint terminating in three 
falciform claws, one of which is more slender than the rest, bearing 
near the extremity of the inner margin two short and stout spines, 
and beset with several (10-12) long slender hairs. 
One adult and one young specimen of this species were washed 
from among the roots of Algz gathered between tide-marks in 
Roundstone Bay, Ireland, by Mr. David Robertson. I am not sure 
that it is rightly referred to the genus Trombidium ; but it seems to 
agree with Dugés’s definition in most respects. The animal was so 
much mutilated in the process of examination that I have not been 
able to give a perfect figure, nor have I succeeded in getting a satis- 
factory view of the mouth-apparatus. 
Genus Pacuyenatruus, Dugés. 
. Pacuyenatuus norops, Gosse, Ann. & Mag. Nat. Hist. ser. 2, 
vol. xvi. (1855), pl. 8. figs. 1-4. 
“Body flat, sinuated, pointed behind, black ; one eye on the 
back ; legs equal, the first and second remote from the third and 
fourth, hairy ; the last joint the longest. 
“Length ;!; of an inch. Body lozenge-shaped or somewhat 7- 
