112 CALIFORNIA ACADEMY OF SCIENCES. 



PLATE XL. 



PONTODRILUS MICHAELSENI. 



74. Cross-sectiou through the body-wall and through the uephi-opore and wide duct. The latter is seen to enter 



the glandular neck of the uephridium [nee), its inner duct having been cut twice, these cross-sections 

 being always of unequal width. The section a passes through the distal windings of the ducts, the letters 

 in the duct indicating that they belong to the same duct. c. c. ciliated canal, always wider than the other. 

 The canal c. is a branch or forking of one of the other ducts. At d. about an inch of the drawing is left out 

 in order to economize room. 



75. Longitudinal section of the nephridium near the windings showing the forkings of one of the canals, c. c. is 



the ciliated larger canal, b. is the body of the nephridium, in which are seen the branched canals and lacunes, 

 as well as the branching blood vessels which are held back. 



76. Part of the neck in cross-section, a larger magnification of a section similar to a 74, showing the branching of 



the narrow duct »i. d. The wide duct v.\ d. t. is cut twice; the jjart marked v). d. is the part of the wide duct 

 as it leaves the neck for the exterior pore of the body- wall. 



ECLIPIDRILUS FEIGIDUS. 



77. A diagrammatic view of the anterior somites of the body, composed from several longitudinal sections. Only 



part of the vascular system is shown, and none of the nephridia, the principal object being to 

 show the arrangement of the reproductive organs and the shape of the alimentary canal. Sperm-sacs not 

 shown, hr. brain. Id. body-wall. phx. pharynx, c c. connecting vessels, d. v. dorsal vessel, c. v. 

 ventral vessel, c?. clitellum. v.r. ventral nerve cord. (. first and second pair of testes. .<;<<A. spermatheca. 

 Oil. ovary, ovd. oviduct, c. r. inner and outer ciliated rosette, cl. clitellar layer of glands, sps. 

 spermatozoa. t. testes. chlo. chloragogeu cells. i male pore. ;). penis. atr. <t j""- prostate and 

 atrium, pr. m. muscular layer of prostate, pr. g. glandular part of prostate, air. atrium, sir. storage 

 chamber for protozoa, s-prf. spermduct. ;«<. intestine. 6r. bridge. 



