410 FRANK E. BEDDAKD. 



EXPLANATION OF PLATES XXX and XXXI, 



Illustrating Mr. Frank E. Beddard's paper " On the Occur- 

 rence of Numerous Nephridia in the same Segment in 

 Certain Earthworms, and on the Relationship between the 

 Excretory System in the Annelida and in the Platy- 

 helminths." 



PLATE XXX. 

 Figs. 1 — 6. — Acanthodrilus multiporus. 



Fig. 1. Transverse section through body wall of 8th segment, o. Ex- 

 ternal orifice of nepbridium. b. Nepbridium brandling in the body 

 wall and opening by several (three) orifices. 



Fig. 2. Transverse section of one half of circumference of body wall of 

 one of post-clitellar segments, s. Setae, n. Nerve -cord. p. Peri- 

 toneum, u, b. Nepbridial tubes. 



Fig. 3. Similar section of a neigbouring segment ; lettering as in last 

 figure. 



Fig. 4. Highly magnified section to show the course of a single nepbridial 

 tubule through the body wall. ep. Epidermis, m. Circular, m'. Longi- 

 tudinal muscles, p. Peritoneum, c. Connective tissue, a, b. Nepbri- 

 dial tube. 



Fig. 5. — Highly magnified section to illustrate the course of a nepbridial 

 tube within the substance of the peritoneum. Lettering as in last 

 figure. 



Fig. 6. Section through a single nepbridial tube passing through the 

 body wall, a, b. Nepbridium. Other letters as in Fig. 4. 



Figs. 7 — 11. — Perichseta aspergillum. 



Fig. 7. Longitudinal section through part of two adjacent segments. 

 cp. Spermatheca. n. Nephridia. s. Intersegmental septum. Other 

 letters as in Fig. 4. 



Fig. 8. Transverse section of nephridiopore, highly magnified, n. Ne- 

 phridium. Other letters as in Fig. 4. 



Fig. 9. Transverse section through a portion of the body wall to show 

 the nephridiopores. np. Nephridiopores. e. Epidermis, s. Seta?. 



Fig. 10. Section through a single nepbridial tube, passing through the 

 body wall. bl. Blood-vessels. Other letters as in Fig. 6. 



