1 90 



AN- INTRODUCTION TO ZOOLOGY. 



to unite domestic virtue with athletic prowess, for all 

 the tribe are noted for their care of their young. The 

 Fresh-water Shrimp [Gammarus) has been watched 

 sheltering its young under the edges of its appen- 

 dages (flat plates called oostegifees, forming a broad 

 pouch in which the young are carried), as a hen does 

 her chickens under her wings, when the water that 

 contained the family was purposely disturbed. The 

 wood-lice [Oniscidce) are another familiar form, be- 

 longing to the Isopods (equal-footed). The English 

 wood-lice belong to the genera Oniscus, Porcellio, and 



Fig. 61. Fig. 62. 



Fig. 61.— A Woodlouse (0«.iscus mumrias). Fig. 62.— A Trllobite (Asaphiis 



candatus). 



Armadillo, and some of them can roll themselves up 

 like a ball, if frightened. Like the sand-hoppers, 

 they carry the young about in a pouch, formed of the 

 modified edges of their appendages. They eat soft 

 wood and roots, etc., and do great mischief in gardens 

 and greenhouses. The fossil irilobites are believed to 

 be related to them : they also had the habit of curling 

 themselves into a ball. Little trace is found of any- 

 thing but the dorsal shell of the body, and their 

 nature is therefore not certain. 



