164 A. RICHARDS. 



EXPLANATION OF PLATE I. 



Photomicrographs were made with a Leitz no. 3 objective and no. 2 ocular except 

 IV. in which a no. i ocular was used. All figures were drawn with a Zeiss compen- 

 sating ocular no. 12 and a 1.5 mm. objective at table level with the aid of a camera 

 lucida, giving a magnification of about 3,500 diameters. 



PHOTO. I. End of a section through a young proglottid, showing the primary 

 anlage of the female reproductive organs. 



PHOTO. II. Primary anlage differentiated into the anlagen of the ovary, vitel- 

 larium and oviduct. 



PHOTO. III. Later stage showing finger-like processes of the ovary. Dorsal 

 to the middle of the ovary is the tip of the vitellarium. 



PHOTO. IV. Stage of maximum development, exc, excretory canal; od, 

 oviduct; v.t, vitellarium; vt.d, vitello duct; ov, ovary; ut, uterus; /, testes; f.d, fertil- 

 ization duct; s.r, seminal receptacle. 



