EXPLANATION OF PLATE XXVIIL 



Fig. 7. — Transverse section through the transverse intestine 

 and excretory vesicles. X68|. (r/5/8.) 



Fig. 8. — Left half of a transverse section in front of the 

 atrium showing the excretory duct and left branch of the intes- 

 tine. X 100. (1/5/ end.) 



Fig. 9. — Portion of a transverse section through the atrial 

 bulb in front of the atrial pore, showing the terminal portion of 

 the penis in longitudinal section, and the male and female atria. 



Fig. 10. — Portion of a transverse section at the level of the 

 centre of the circlet of atrial spines. Shows the atrial bulb with 

 the male and female atria, and the opening of the seminal vesicle 

 into the canal of the penis. Xioo. (2/1/ end.) 



VtQ. Ti. — A spine of the atrial circlet, with the pomt of a 

 second spine, from the same section as fig". 10. X 1000. 



Fig. 12. — Portion of a transverse section immediately in front 

 of the utelrus, showing the seminal vesicle and anterior uterine 

 duct. X 100. 



Fig. 13. — Portion of a transverse section at the level of the 

 uterus showing uterus and the seminal vesicle. X 100. (2/3/^.) 



