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AN ELEMENTARY TEXT-BOOK OF BIOLOGY. 



Fig. 27. APPENDAGES or ASTACUS, Right side. A and A', Upper and 

 lower views of antennule ; B, antenna ; C, mandible ; D, mx. 1 ; 

 E, mx. 2 ; F, mxpd. 1 ; G, mxpd. 2 ; H, mxpd. 3 ; I, base of third 

 walking-leg; K and L, 1st and 2nd abdominal appendages of male; 

 M, typical swimt.; N, arthrobranchia ; pr, protopodite; en, endopodite; 

 ex, exopodite ; ep, epipodite ; c. s, coxopoditic setse ; sg, scaphognathite ; 

 au, auditory opening. 



