STUDIES ON EARTHWORMS. 571 



Pig. 3. — The free end more biglily magnified, (x 300.) 



Fig. 4. — A transverse section through the middle portion of the wall of 

 the cocoon. ( X 300.) a. Outer layer, b. Middle layer, c. Inner layer. 



Fig. 5. — A detached piece of the middle layer, (x 300.) 



Fig. 6.— Strata of the inner layer, (x 300.) 



Fig. 7.— a spermatophore. (x 60.) 



Fig. 8. — Spermatozoa from the spermatophore. (x 500.) 



Fig. 9. — The anterior extremity of the worm viewed from above, (x 2, 

 spirit specimen.) a. The prostomium. b. The dorsal setse. c. Enlargement 

 occupying somites xiv to xviii, due to the large papillae on the ventral sur- 

 face, d. The clitellum. Behind somite xlv the quadrangular shape of the 

 worm is shown. 



Fig. 10. — The same worm from below, a. The prostomium. b. The 

 mouth, c. The pore of the oviduct, d. The pore of the sperm-duct, situated 

 on a large rounded swelling causing the enlargement in this region, e. The 

 ventral setse. f. The clitellum. 



Fig. 11. — The last few somites of the body, showing : — a. The anus, 

 situated dorsal^ly. b. The region regarded by Vejdovsky as representing seven 

 or eight fused somites. 



Fig. 12. — A diagrammatic outline of a section through the body in the 

 posterior region of the body, showing its quadrangular shape, with the dorsal 

 setae {a) and the ventral setae (b) placed at the corners. 



Fig. 13. — The side of the body, showing a spermatophore (a) attached to 

 somite xiv. b. dorsal setae, c. The ventral setae, d. The sperm-pore, on its 

 enlarged papilla, e. The ovipore. 



Fig. 14. — General view of the anatomy of Criodrilus when opened in the 

 usual way. (x 2.) a. The pharynx, b. The oesophagus, swelling out at c 

 to form a strong muscular crop. d. The intestine, e. The dorsal blood- 

 vessel. /./. The lateral hearts, g. g. The seminal reservoirs, h. The ovary. 

 h. The ovisac (Bergh's " receptaculum ovorum "). /. The hemispherical 

 glandular swelling or prostate around the terminal portion of the sperm-duct. 

 m. Prostomium. n. Suprapharyngeal ganglia, o. The nephridia. 



Fig. 15.— The genital organs of the left side greatly enlarged. A portion 

 of the oesophagus is represented on the right of the figure, a. a'. The two 

 testes, b, b' , The ciliated rosettes, c. The sperm-duct, which dips into the 

 hemispherical prostate, d. The seminal reservoirs, e^, e", e^, e*, are represented 

 as relatively rather smaller than their true size ; they are seen to be attached to 

 the various septa. /. The ovary. The septum between the somites xiii and 

 XIV is turned back so as to show the funnel of the oviduct,,^, and the nephri. 

 dial funnel, /. h. The ovisac, k. Nephridium. 



Fig. 16. — A testis attached to the septum. 



