200 THE CRAYFISH. PHYLUM ARTHROPODA 



These are quite different from the chsets of the earthworm ; 

 thev are hollow, and the epidermis is continued mto them and 

 is here often connected with nerve fibres, so that the bristles 



Fig. 134. — A ventral view of a female crayfish, with the limbs of the right side 

 removed and the branchiostegite of that side partly cut away. — Partly 

 after Howes. 



ab.l.ifi, First and sixth abdominal limbs ; at.i, antennule ; at.2, antenna ; an., anus ; br., branchiostegite ; 



e.g., cervical groove ; ch., cheliped ; en., endopodite ; en.sk., endophragmal skeleton ; epm., epimeron ; 



ex. exopodite ; g.c, gill chamber ; g.op., openings of oviduct ; Ibr., labrum ; m.l., limbs adjoining the 



■, mxp.2, third maxilliped ; pi., pleuron ; pr., protopodite ; rst., rostrum ; st.ab., abdominal 



z'.h., sternal region of body in part of mouth st.th., thoracic sterna ; t., telson ; t.g., tubercle 



-'•.. ■ ..L^ green gland opens ; w.l.i, first walking leg. 



