DESCRIPTION OF PLATES XI. and XII. 



Fig. I. — DiagiLimmatic represeutatiuu of a sextaut iu Aciin'ia. — {a) 

 Primary, (6) Secondary, (c) Tertiary, and {0.) Quaternary septa- 

 Figs. 2 & 8. — Fluted organ of A. iire.<e>nhrijantheiuani (see text). — («) Sep- 

 tum, ('./) White spots. 

 Fig. 3. — Transverse section of a sextaut of .4. iiu'semhrijantheiniu)/, made 



close under the disc. 

 Fig. 4. — Ditto, made half-way down. 

 Fig. 5. — Base of ditto. 

 Fig. 6 — Tertiary septum of .4. raest'inhrtjautheinain, with eggs; craspedum 



cut away ; fluted organ iu wavy line. 

 Fig. 1. — Quaternary septum of S. parasitica ; early ovarian stage (Sep- 

 tember). No craspedum carried by this septum ; fluted organ seen 

 lifted up. 

 Fig. 9. — Quaternary septuui of T. cra.'isicornis ; craspedum at foot and 

 edging septum, and followed by fluted organ running to back of 

 stomach Avail ; eggs cover septum. 

 Fig 10. — Eggs of S.yarasitica. 

 Fig. 11. — Quaternary septum of S. parasitica ; advanced ovarian stage 



(Noveuiber) ; fluted organ removed. 

 Fig. 12. — Fluted organ in S. parasitira, showing keel-like process. 

 Fig. 13. — Marks seen through disc of -1. lucseiabryaiitheiiiaiiv (tiCQ text). 

 Fig. 14. — Relative shapes of the four septa in ditto. 

 Fig. 15. — Marks seen through disc of ,S'. para.sitii-a. 



