52 TROGRESS OF VETERINARY SCIENCE AND ART. 
Fig. 8. — Acarus hippopodos, of canker of the foot of the horse. Cha- 
racterised by the acute shape of its body in front ; no fila- 
mentary organs, but long tarsal discs to its hind feet, and 
eight feathered hairs, four long and four short, from posterior 
part of the body; the whole body is finely haired. Its 
greatest length is 0T6, breadth from 008 to CH385 of a 
Paris line. 
— 9. — Acarus setosus , from skin of man, after Thudichum. Supposed 
to exist also in the ox. Same characters as Acarus hippo- 
podos , excepc the hairiness of body ; scanty, erect bristles, 
however, spring from papillae in different parts, which are 
wanting in A . hippopodos. The number and arrangement 
of the filamentary organs differ in the two. (Thudichum.) 
— 10, 11 — The insect of scabies in the cat, viewed, from above and 
below, after Hering. Third pair of feet with a long fila- 
mentary organ, without tarsal discs ; but two thorn-like 
appendages. Fourth pair of legs short, ending in a short 
tarsal disc, and a thorn-like appendage. The smallest of all 
known acari, measuring from CK)54 to O061 of a French 
line in length, and from 0’048 to 0*054 of a line in breadth. 
— 12. — The animal of the sebaceous gland; Lemodex folliculorum 
(Owen) : a side view. This animal has been found in man, 
the horse, and the dog, and probably exists in association 
with torpidity of the sebaceous organs in all animals. (Wilson.) 
Thoracic appendages {c c c c ), eight in number, terminated 
by three short setae, retaining the Anellidous type. Mouth 
suctorial, or proboscidiform, consisting of two small spine- 
shaped maxillae (£), and an extensile labrum, capable of being 
elongated and retracted ; it is provided on each side with a 
short and thick maxillary pulp [aa\ consisting of two joints, 
and with a narrow triangular labrum above. (Owen.) 
VALUE OF ALUMINIUM. 
Already the new metal aluminium has been proved of 
practical utility, since an alloy of 2 equiv. of it and 3 equiv. of 
iron does not oxidize when exposed to a moist atmosphere, 
although it contains 15 per cent, of iron. 
