174 FRANK E. BEDDARD. 



DESCRIPTION OF PLATE XX, 



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

 of a Species of Earthworm belonging to the Genus 

 Diachseta." 



Diachseta Windlei. 



Tig. 1. — Ventral view of anterior segments, to illustrate arrangement of 

 setae and their disappearance from the first five segments. 



Fig. 2. — Front view of first segments, to show absence of prostomium. 



Figs. 3 and 4.— Hooked setae of posterior segments. 



Fig. 5. — Setae of middle segment. 



Fig. 6, — Setae of anterior segments, a. Seta of larger size. 



Fig. 7. — Extremity of one of these setae, more highly magnified to show 

 ridges. 



Fig. 8. — Tail end of body, 5. Large hooked setae, m. Muscles moving 

 them. I. Last segment, i. Intersegmental groove. 



Fig. 9. — Semi-diagrammatic longitudinal view. c. Brain, npli. Aperture 

 of anterior nephridia. g. Gizzard, sp. Spermathecae pore. t. Testes, vs. 

 Sperm-sacs. gl. Calciferous gland. v. d.f. Funnels of vasa deferentia. 

 ov. Ovary, od. Oviduct. The segments are numbered. 



Fig. 10.— Longitudinal section through calciferous gland, oe. CEsophagus 

 *. Septa, ca. Gland. 



Fig. 11. — A portion of ditto more highly magnified, p. Peritoneal cover- 

 ing. /, /. Muscular layers, bl. Blood-space, ep. Epithelium. 



Fig. 12. — Section through point of opening of heart into ventral vessel. 

 h. Heart, b. Ventral vessel, v. Valve. 



Fig. 13. — Similar section through opening of heart into dorsal vessel. 

 h. Heart. b. Dorsal vessel, v. Valve, a. Fibrous matter contained in 

 blood. 



Fig. 14. — Sphincter {sph.) at aperture of nephridium («/?.). 



Fig. 15. — Section through body -wall in middle of Segment vii or vni. ep. 

 Epidermis, tr. Transverse muscles. I. Longitudinal muscles, .r. A tract of 

 transversely running fibres enclosed in a sei)Hra(e fibrous sheath. 



