CRUSTACEA 



337 



then the shape of the limb is maintained largely by the pressure of 

 blood within it. In these cases the flexibility is such that no joints are 

 needed. There is in this limb an axial portion or corm which bears on 

 the median side a row of lobes known as endites, and on the outer side 

 one or more lobes known as exiles. Of the latter the more distal, 

 standing usually opposite the third or fourth endite from the base and 

 often known as the flabellum, is the homologue of the exopodite of the 

 biramous limb. Exites proximal to this are epipodites. That next to 

 the flabellum is the branchia (metepipodite) ; any which may be pre- 



5— 



2--4— 





Fig. 223. 



Fig. 224. 



Fig. 223. The second thoracic limb of Anaspides. After Caiman, with an 

 addition, en. endopodite; ep. epipodite; ex. exopodite ; ^jc. flexure of limb; 

 I, position of precoxa or pleuropodite, represented, according to Hansen, by 

 an isolated area of chitinization of the thoracic wall; 2, coxa or coxopodite; 

 3, basis or basipodite (probasipodite) ; 4, preischium or metabasipodite; 

 5, ischium or ischiopodite ; 6, merus or meropodite; 7, carpus or carpopodite; 

 8, propus or propodite; 9, dactylus or dactylopodite (apical joint). 



Fig. 224. Tenth thoracic limb of Apiis. br. branchia; flb. flabellum; gn. 

 gnathobase; ep. epipodite; ex. exopodite; 1-5, segments of the limb; z'-^'t 

 endites; 6, last endite or apical lobe. 



sent proximal to the branchia are proepipodites (Fig. 238, pr. ep.). The 

 flabellum typically overhangs its attachment proximally as well as 

 distally. In the latter direction it may extend so far as to form with 

 the distal part of the corm a pair of equal rami (Fig. 222 C). The 

 homology of the endopodite then becomes apparent. This ramus 

 corresponds to that part of the corm of the phyllopodium which is 

 distal to the insertion of the flabellum or exopodite. Of the endites ^ 

 that which stands at the base of the limb is usually diflFerent in form 

 from the rest and used in one way or another for manipulating the 



