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REPORT ON ZOOLOGY, MDCCCXLII : 
on the point of the maxillary lobes ; living on the ground. The first 
family, Trombidides, have free fusiform palpi, the penultimate joint of 
which resembles a claw, and the terminal joint is articulated at its base, 
as an immoveable appendage ; the eyes are on a little projection at the 
sides of the proboscis : Confined to the genus Tromhidium, F., composed 
of thirty-five species, among which 1\ grandissimum, from the Cape ; 
T. harhatum, from Senegal ; T. flavipes, from the south of F ranee ; T. 
hirsutissimum, from Greece, are described, and figured as new. The 
second family, Rhyncolophides, the author distinguishes, by the eyes 
being placed sidewards on the back of the anterior part of the body : It 
contains the genera RhyncolopJms, Dug. ; Smaridia, Dug. ; Erythreeus, 
Latr, ; Stigmwus, K. ; Caligonus, K. ; Raphignathus, Dug. ; Actineda, 
K. ; Tetranychus, Dug. 
A fourth division, the Running-acari, is formed of such as have 
six-jointed legs, and a small pair of nippers at the point of the maxillary 
lobes. The only family, Eupodides, has two small, scarcely visible eyes, 
the fore and after parts of body distinctly separated from each other, 
free fusiform palpi, and a short proboscis, elongated fore-legs, serving for 
walking and feeling, and contains the genera Bryohia, Scyphius, Penta- 
leiis, Linopodes, Eupodes, Tydeus, K., which prefer moist places. 
Gervais has noticed various Acari (Ann. d. 1. Soc. Ent. d. Fr. xi. p. 
46) ; Holothyrus is a new genus of the family of the Oribatidee, with 
its body convex above, shield-shaped, flat beneath, marginated laterally, 
the upper surface consisting of a single piece ; no eyes, long four -jointed 
moveable palpi, legs long, and with claws : one species, H. coccinella, 
locality unknown. Dermanyssus coriaceus, living on the wings of the 
Vespertilio noctula ; another Dermanyssus was found under the scales 
of Coluber natrioc. Ixodes Walkenoeri, from the rhinoceros ; I. Bibroni, 
from a boa ; I. coxalis, from a New Holland skink, are also named. 
Gurlt has given an admirable representation of the Acari living as 
parasites on domestic animals. (Magaz. f. d. ges. Thierheilk, ix. Jahrg. 
1. St. p. 18, t. 1.) 
A discovery of Dr. G. Simon has attracted much attention, viz., — that 
of an Acarus living in the human skin (Miill. Arch. f. Anat. u. Physiol. 
1842, p. 218, t. 11). Henle has also found the same animal, and given 
an account of it in the Zurich “ Oflentlichen Beobachter” (Dec. 1841). 
He, however, so far mistook the nature of the animal, as to consider it 
as an intestinal worm. At a later period (Bericht fiber die Verhandl. d. 
Naturf. Gesellsch. in Basel v. p. 191) Miescher also communicated his 
observations upon it, which confirm, in general, those of Simon, and in 
individual cases are more ample. Simon found Acari of long, first 
in comedones, and soon after in healthy hair-sacs of the human skin ; 
and it was soon evident, that they might be there without being pre- 
judicial. Usually only one Acarus was found in a hair-sac, sometimes 
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