ON THE CCELOW, GENITAL DUCTS, AND NEPHEIDIA. 509 



EXPLANATION OF PLATES 44 & 45, 



Illustrating Mr. Edwin S. Goodrich's paper on "The 

 Coelom, Genital Ducts, and Nephridia." 



Reference Letters. 



c. Ccelomic or genital follicle. e]p. i. Epidermal invagination, neph. True 

 nephridium. p.f. Peritoneal funnel developed from the ccp-lomic epithelium. 



In all the diagrams the outline of the ccElom, the peritoneal funnels, and the 

 genital cells, are drawn in red. The epiblast and hypoblast are darkly shaded. 

 The mesoblast is lightly shaded. The true nephridia are drawn in black. 



Fig. 1. — Diagrammatic plan of the ccelom, genital ducts, and nephridia in 

 the Planaria. 



Fig. 2. — Similar plan of a young Nemertine. 



Fig. 3. — Plan of a mature Nemertine. 



Fig. 4. — Plan of the ccelom, &c., in the Entoprocta. 



Fig. 5. — Plan of the ccelom and nephridium in an embryo Oligochsete. 



Fig. 6. — Later stage of the same, showing the nephridia in the pronephri- 

 dial condition. 



Fig. 7. — Plan of the ccelom, &c., in an adult Oligochaete (Lumbricus). 



Fig. 8. — Plan of the ccelom and nephridia in an embryo leech. 



Fig. 9. — Plan of the ccelom, &c., in the Hirudinea. 



Fig. 10. — Plan of the ccelom and nephridia in an embryo Polychsete. 



Fig. 11. — Later stage of the same, showing the pronephridium about to 

 fuse with the peritoneal funnel. 



Fig. 12. — Plan of the ccelom, &c., in the Polychseta possessing wide-mouthed 

 *' compound nephridia," the nephridium having fused with the peritoneal 

 funnel. 



Fig. 13. — Plan of the coelom, &c., in certain segments of Tremomastus and 

 Dasybranchus in which the nephridial funnel is continuous with the genital or 

 peritoneal funnel. 



Fig. 14. — Plan of the ccelom, &c., in certain segments of Dasybranchus 

 caducus, in which the nephridial funnels are independent of the peritoneal 

 funnels. 



Fig. 15. — Plan of the coelom and developing peritoneal funnels in an embryo 

 Peripatus. 



Fig. 16. — Plan of tlie coelom and peritoneal funnels in a trunk segment of 

 Peripatus. The ccelomic follicles on either side have become separated into a 

 ventral and a dorsal portion, forming the genital tube. 



