SPECIES, AND SPECIES. 173 



hairs ; and, particularly, by its habits, our wood-louse, which 

 the Germans call cellar-louse (Kellerlaus), is distinguished from 

 its kindred species, of which naturalists have made distinct 

 genera. Thus, the asellus found generally under stones, which 

 counterfeits death by rolling itself up in a ball like a hedgehog, 

 and will rather suffer itself to be crushed than unfold, is the 

 Oniscus armadillo, which some naturalists transform into the 

 Armadillo vulgdris. (See Fig. 36.) This species prefers the 

 solitude of the field to inhabited places. Its body is con- 

 siderably expanded, and its rings do not terminate in a point 

 on their lateral and posterior edges. 



Another species, equally common underneath stones, has 

 its head and tail covered over with granulations ; its 

 antennas are composed of seven joints, of which the 

 fourth and fifth are perceptibly situated lengthwise. FIG. 3 6. 



. . . Oniscus 



This is the Oniscus granulatus of some entomologists ; armadillo. 

 others have designated it the Porcellio scaber. Why not sim- 

 plify the study of species ? 



The wood-lice seem to live upon decomposed vegetable 

 matter. But in default of other food, they devour their own 

 kind ; in this respect resembling beings who are supposed to 

 rank much higher in the animal hierarchy. 



In the pharmacopoeia of the ancients our wood-lice found a 

 place. Reduced into powder, and mixed with various sub- 

 stances, they were prescribed as diuretic and aperient; but 

 they were long ago abandoned in medicine. 



