134 THE CRAYFISH 



iii. The exopodite is slender, and consists of a long 

 proximal joint and a distal many -jointed fila- 

 ment. 



VII. The second maxillipede is smaller and less firmly- 

 calcified than VIII., which it resembles in form ; 

 but the exopodite is larger than in VIII., and 

 the endopodite smaller, its largest joint being the 

 meropodite, and all its joints being movable. 



VI. The first maxillipede is smaller and softer than 

 VII. 

 i. The two joints of the protopodite are expanded- 

 on the inner side, forming a large two-lobed 

 lamella. A broad plate, the epipodite, takes- 

 the place of a gill, 

 ii. The endopodite is very small and two-jointed, 

 iii. The exopodite resembles that of VII. 



3. The head appendages consist of three pairs of oral 

 appendages or jaws, V. to III., placed at the sides of 

 the mouth, and two pairs of pre-oral appendages, 

 II. and I., at the front of the head. 



7. The second maxilla consists of a protopodite, an 

 endopodite, and on the outer side an organ sub- 

 servient to respiration, the scaphognathite. 

 i. The protopodite consists of two joints, coxopodite 

 and basipodite, each of which is expanded on 

 its inner side into a bilobed lamella, 

 ii. The endopodite is small, pointed, and unjointed. 

 iii. The scaphognathite is an elongated plate at- 

 tached by the middle of its inner edge to the 

 outer side of the protopodite. It may be 

 regarded as the exopodite and epipodite fused 

 together. It serves to keep a current of water 

 flowing through the gill-chamber (p. 139). 



rV. The first maxilla is small. The two joints of the 

 protopodite extendinwards as thin curved lamellae. 



