438 JBRO-SPIRANTIA. 
Division—AZRO-SPIRANTIA. 
We have now arrived at that division of the order 
Isopoda which comprises the species that differ from 
the great majority of those animals, and indeed (with the 
exception of the land-crabs) from the remainder of the 
class Crustacea, in the manner in which respiration is 
effected; these animals residing, not in water, but in 
damp situations, and breathing air, which, however, it is 
necessary should be saturated with moisture, as has been 
fully proved by a careful series of experiments published 
by Messrs. Duvernoy and Lereboullet in the “ Annales 
des Sciences Naturelles,” 2nd series, Zool., tom. 15, 
p- 205. The specialized structures by which this is 
effected will be noticed below. We must here, however, 
refer to the exceedingly interesting genus, Tylos of 
Latreille, founded upon an Egyptian species elaborately 
illustrated by Savigny in the great work on Egypt 
(Crust. pl. 13, f. 1), in which respiration is effected in a 
double manner, namely, by the action of the water or 
moistened air on the external surface of the respiratory 
branchial plates or false legs on the underside of the 
tail, in the same manner as in the Idotez and other 
normal Isopods, and by the inspiration of air by means 
of certain spiracular orifices on several of the basal pairs 
of these same appendages. We have searched in other 
genera for these peculiar organs, but without hitherto 
being successful. 
The division, which corresponds with the family 
Cloportides of Latreille and Milne Edwards, comprises 
the single 
