352 



PHYLUM ARTHROPODA 



fresh water, and sandhoppers like Talitrus and Orchestia : the " no 

 body " crabs, Caprella ; Phronima, living inside the glassy case of 

 the free-swimming Tunicate Pyrosoma. 



Division 3. Hoplocarida, with a carapace that leaves at least four 

 of the thoracic segments free, with stalked eyes, with the eggs carried 

 in a chamber formed by the maxillipedes, with an elongated heart. 



abd 



Fig. 197. — Hermit-crab withdrawn from its shell. 

 The anterior appendages are broken off. 



hd., Head ; th., thorax ; abd., abdomen. 



and with a complicated metamorphosis. Order : — Stomatopods, e.g. 

 SqiiiUa, with the second maxillipedes forming very large raptorial 



organs. 



Division 4. Eucarida, with a cephalo-thoracic shield uniting the 

 head and thorax segments ; with stalked eyes ; with a saccular heart ; 

 with eggs attached to the abdominal endopodites ; with spherical 

 spermatozoa showing peculiar radiating pseudopodia ; usually with a 

 complex metamorphosis. 



