EXPLANATION OF PLATES 



PLATE I. 



Fig. I. Perichaeta indica. 

 Dissected, sp, spermathecae ; g, gizzard ; sp s, sperm-sac ; dv, dorsal vessel ; wph, nephridia ; 

 sp gl, spermiducal gland ; caec, caeca. 



Fig. 2. Perichaeta everetti. 

 Ventral view of anterior segments, sp, spermathecal pores ; ? oviducal pore ; (J male pores. 



Fig. 3. Polytoreutus magUensis. 

 Ventral view of anterior segments. (J male pore ; sp p, pore of spermathecal sac. 



Fig. 4. Octochaettis muUiporus. 

 Dissected slightly from the side, gl, peptonephridium ; g, gizzard ; nph, nephridia ; dv, dorsal 

 vessel ; sp gl, spermiducal glands ; n, nerve-cord ; v v, ventral blood-vessel. 



F'g- 5- Perichaeta posihuma. 

 Ventral view of worm ; ? oviducal pore ; (J male pores ; p, genital papillae. 



Fig. 6. Libyodrilus violaceus. 

 sp p, spermathecal pore ; ^ male pore. 



Fig. 7. Eudrilus eugeniae. 

 $ female pore : (J male pore. 



PLATES II AND III. 



Generative organs of various types of Oligochaeta diagrammatically represented. The male 

 organs are coloured pink, the female blue. To ail the figures the following lettering applies : 

 T, testes ; F, sperm-duct funnels ; sp s, sperm-sacs ; o, ovary ; od, oviduct ; e s, e^-sacs ; os, sper- 

 mathecal sac ; sp, spermathecae ; sp gl, spermiducal gland. 



PLATE IV. 



Fig. I. Libyodrilus. 

 Dissection, o, orifice of spermathecal sac ; sps, sperm-sacs ; sp gl, spermiducal glands ; 

 vv, ventral blood-vessel ; dv, dorsal blood-vessel ; n, nephridia. 



Fig. 2. Siphonogaster miUsoni. 



Tt, penial (?) processes. 



The remaining figures bear a legend. In all of them the following is the significance of the 

 letters : g, gizzard ; ea, calciferous glands ; sp, spermathecae ; sp s, sperm-sacs ; h, ' heart ' ; sp gl, 

 spermiducal glands ; vd, vas deferens ; od, oviduct. 



The clitellar segments are numbered ; the dorsal vessel with its branches are coloured red. 



