136 



FIRST BOOK OF ZOOLOGY. 



This feature is characteristic of the class to which these ani- 

 mals belong. How different in this respect from the creat- 

 ures already studied, in which the eggs are deposited and 

 left by the animal ! It has been learned that certain spiders 

 too carry their eggs round with them, and protect them. 



BITING -JAW Mandible . 



LITTLE JAWS OK ACCES- i 



SORT JAWS, OR MAXIL- -| 



f First Maxilla . 



Second Maxilla. 



f First MaxilUped . . 



FOOT-JAWS, OR MA STL 



LIPEDES. 



/Second Maxilliped 



. Third Maxillijjed 



FIG. 126. MOUTH-PARTS OF A CRAWFISH FROM TIIE LEFT SIDE. 



Fig. 128 represents a crab carrying its eggs glued to the 

 appendages on the under surface of the abdomen. Pupils 

 having access to lobsters in the markets, will, by looking over 

 them, find some specimens in which the eggs are being carried 

 in this way. 



126. The young animal in growing sheds its entire shell, 



