78 THE ZOOLOGIST. 
overcome; and, by keeping specimens under observation in a 
living state, he has succeeded in watching them through the 
various stages to the adult condition, tracing their development 
and noting many a curious fact in their life-history. 
Dissecting them under the microscope, he has carefully 
ascertained the nature of their structure, which he has illustrated 
in detail in a series of beautifully-executed plates, and, in dealing 
with their life-history, has furnished an account which rivals in 
interest Darwin's observations on the habits of Earthworms, and 
Sir John Lubbock’s experiments on Ants and Bees. 
In marked contradistinction to all other groups of Acarina, 
the Oribatide at every stage of their existence are free organisms, 
not in any way parasitic, and not looking for any host either for 
nutriment or conveyance. 
All the members of the family appear to be vegetable feeders, 
although Mr. Michael seems to be a little doubtful about Pelops, 
and none of them have been found to be injurious to man or his 
works. Their respiration is tracheal. They are extremely slow 
in their movements, sometimes remaining motionless for hours, 
and it is not always easy to distinguish some of the immature 
ones from the vegetable substances upon which they feed. A 
French naturalist, M. Nicolet, has taken the trouble to calculate 
the rate of progress of several species, and Mr. Michael has 
reproduced his table of results, believing them to be “ fairly 
correct.” 
The amount of information elicited by patient research, and 
made known in the work before us, shows how much there is to 
learn about living creatures of whose very existence probably 
many people until now have been quite unaware. 
Nests and Eggs of Australian Birds. By ArncurBaLp J. CAMPBELL. 
8vo, pp. vi; 72; xxx. Illustrated with photographs of the 
eggs. Melbourne: published by the author. /W707F , 
Tue mode of nidification and the character of the egg furnish 
such important indications of the nest-builder’s affinities with 
other species, that well-authenticated specimens of the eggs of 
little-known birds are always welcome additions to a collection 
formed with a scientific object. 
