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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 95 



lateral wall of the gonadial sac (B, D, G, Grin), and in this feature 

 the gonads of certain Collembola preserve the generalized structure 

 of the reproductive organs found in Onychophora, and in arthropods 



Fig. 23. — Hexapoda-Collembola : internal genitalia. 



A, Amirida marithna, diagram of position of male gonads (from Imms, 1906). 

 B, Amirophoriis lands, outline of testes showing position of germaria (from 

 Lecaillon, 1902a). C, Amirida maritima, transverse section through fourth ab- 

 dominal segment (from Imms, 1906). D, Amirophorus laricis, transverse sec- 

 tion of testis, showing germarium in dorsal wall (from Lecaillon, 1902a). E, 

 Anurida maritima, longitudinal section of posterior part of testis, showing 

 bundles of spermatozoa separated by ingrowths of epithelial wall (from Imms, 

 1906). F, Podura aquatica, mature testis, dorsal view (from Willem, 1900). 

 G, Tomocerus vulgaris, mature testis of right side, dorsal view (from Willem, 

 1900) . 



a, intratesticular ingrowths of testicular epithelium ; BMb, basement membrane ; 

 Dej, ductus ejaculatorius; DMcl, dorsal longitudinal muscles; DV, dorsal blood 

 vessel ; Epth, testicular epithelium ; Ft, fat tissue ; G, gonad, G>rm, germarium ; 

 Sp::, spermatozoa ; Tes, testis ; Vent, ventriculus ; VNC, ventral nerve cord ; 

 Vsm, vesicula seminalis. 



Other than insects in which the germinal cells have not become local- 

 ized in the apex of the gonads or in the apices of lateral diverticula. 

 Within the lumen of the testis the bundles of developing spermatozoa 

 (E, Sps) are enclosed in compartments formed of intratesticular 



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