18 ZOOLOGICAL LITERATURE. 
[On the development and structure of the skin and hairs of 
Bradypus, with notes on an Alga (Pleurococcus) growing in the 
interior of the hairs of the Sloth.] 
^ The author found a nearly mature embryo of Bradypm tridac- 
tylus (cuculligerl) y 26*5 centim. long, enveloped in an amnion- 
like, tight-fitting sac. The embryo presented itself within this 
membrane, covered by a perfectly developed coat of hairs 
nearly an inch long. Microscopical examination, and the cir- 
cumstance of this membrane passing into the outermost coyering 
of the nails and into the epithelium of the mucosa of the mouth 
and umbilical cord, proved that it is not the amnion, but the up- 
permost stratum of the epidermal lamella of the embryo, raised 
by the hairy covering which is developed within this sac, called by 
the author epitricMum, In a younger embryo, 24*5 centim. long, 
the hairs are not developed, and consequently no epitrichium is 
formed. Such an epitrichium is found in CholoepuSj Myrmeco- 
phagUj DicotyleSf Sus, and probably in the Horse ; and absent 
in JDasypus, CmlogenySj Basyprocta, Hydrochoerus^ CervuSj Ovis, 
BoSj Bidelphys, Ursus, Felis, and in Man. The remainder of 
the memoir treats of the structure of the hair of BradypiiSj and 
jof an Alga growing in the interior of the hair. 
D. Publications of a Popular Character. 
Brehm, B. L., und Zimmermann, Th. F. Bilder und Skizzen 
aus der Thim‘welt im zoologischen Garten zu Hamburg. 
Liegnitz, 1865. 8vo. pp. 283, with 26 illustrations. 
This book contains the description of a new species of Deer, 
named Rusa paradoxa (see below) . 
Cornelius, C. Die Zug- und Wanderthiere. Berlin, 1865. 
8vo. pp. 341. 
The author treats in systematic order of the animals, from 
the Mammalia to the Mollusca, of which periodical oy isolated 
migrations are known. 
Dumeril, a. Des animaux utiles h Fhomme, programme d^un 
cours de zootechnie ou zoologie appliquee. Mem. Soc, 
Imp. Sc. Nat. Cherbourg, xi. 1865, pp. 229-252. 
Without entering into a detailed enumeration of animals 
useful to man, the author shows in what various ways man de- 
rives benefit from the animal creation. 
Small, H. B. The Animals of North America. Mammals. 
Montreal, 1864. 8vo (pp. 112, with woodcuts). 
A poor popular account of Canadian Mammals, illustrated by 
rude woodcuts. 
