io8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



ondary lobes of the paraprocts. It is highly unlikely that the struc- 

 tures in question are styli, since, as already shown, the paraprocts are 

 not limb bases. Crampton's view regarding the relation of the para- 

 proct process to crustacean exopodites will be discussed in the fol- 

 lowing Section of this paper. 



Cer 



A 



Eppt "p Papt paptl 



20Stn 



•An 



Endpd 



Tel 



Fig. 45. — Terminal appendages of a tridactylid insect and an isopod crustacean. 



A, posterior part of abdomen of Ellipes niinuta (tridactylid orthopteron). 

 B, the same, dorsal view. C, end of abdomen of Porcellio (isopod crustacean), 

 ventral view. D, the same, dorsal view. 



An, anus; Cer, cercus ; Endpd, endopodite; Eppt, epiproct; Expd, exopodite; 

 la, lamina sub-analis ; Papt, paraproct ; paptl, lobe of paraproct ; Prtpd, protop- 

 odite ; sa, lamina supra-analis ; Tel, telsqn (fused with tergum of twentieth 

 segment). 



MORPHOI.OGY OF THE ABDOMINAL APPENDAGES 



There is no need at present to offer proof of the serial identity 

 of the appendicular organs of the insect abdomen with the segmental 

 appendages of the thoracic and cephalic regions of the body. Embry- 

 ologists have amply demonstrated the continuity of appendage rudi- 

 ments on the entire series of primitive somites, at least 20 in all, leav- 

 ing only a prostomial lobe and a periproctial region devoid of true 

 limb structures. To determine the homologies of the parts of the 

 abdominal appendages with the parts of the better developed append- 



