318 SUPPLEMENT 



On the habits of the order L^MODlPODA, we have nothing 

 of any interest to insert. 



On those of the IsopoD order, there is but little to add to 

 the text. 



We shall first notice Oniscus, the subgenus proper of 

 which name is the type of the order, and is composed of the 

 little animals commonly called wood-lice, in this country, and 

 cloportes in France. 



The name cloportides, or oniscides, is given by M. Latreille 

 to a group which comprehends the oniscus of Linnaeus, re- 

 spiring the air in an immediate manner, or which have gills, 

 analogous, as to their properties, to the lungs of vertebrated 

 animals. These Crustacea, with the exception of ligia, are 

 all teiTestrial, and if plunged into the water, will perish there, 

 after a greater or less time. 



The onisci are, in general, very small Crustacea, which sel- 

 dom appear during the day. They usually remain in humid 

 places, under stones, in the clefts of walls, in cellars, and 

 often bury themselves in the earth. They appear to dread 

 the light and heat of the sun. They walk slowly ; but when 

 they are pursued, they endeavour to save themselves by flight, 

 and then they run tolerably fast. 



They feed on different substances, attack and gnaw fruits of 

 all kinds which have fallen to the earth, and also eat the 

 leaves of plants. Degeer has observed small onisci devovn* 

 a large one of their own species, which had been shut up with 

 them, which proves that they are carnivorous. 



The females lay eggs which disclose the young, as it were, 

 in their bodies ; they carry them in a sort of oval sac, slender 

 and flexible, placed underneath their body, and extending 

 from the head towards the fifth pair of feet. When the young 

 are entirely formed, to give them a free issue, the mother 

 opens the sac, or ovary, in which are fonned one longitudinal 

 cleft, and three transverse ones ; then the little ones issue 



