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CALIFORNIA ACADEMY OF SCIENCES. 
PEALE xe: " 
PONTODRILUS MICHAELSENT. 
Cross-section through the body-wall and through the nephropore and wide duct. The latter is seen to enter 
the glandular neck of the nephridium (nec), 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 1s left out 
in order to economize room. 
Longitudinal section of the nephridium near the windings showing the forkings of one of the canals. c. ¢. is 
the ciliated larger canal. 6. 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. 
Part of the neck in cross-section, a larger magnification of a section similar to a 74, showing the branching of 
the narrow duct x. d. The wide duct w. d. ¢. is cut twice; the part marked w. d. is the part of the wide duct 
as it leaves the neck for the exterior pore of the body-wall. 
ECLIPIDRILUS FRIGIDUS. 
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, br. brain. bd. body-wall. pha. pharynx. c.v. connecting vessels. d.v. dorsal vessel. v. v. 
ventral vessel. cl. clitellum. v.c. ventral nerve cord. ¢. first and second pair of testes. spth. spermatheca. 
ov. ovary. ovd. oviduct. c. 7. inner and outer ciliated rosette. cl. clitellar layer of glands.  sps. 
spermatozoa. 1. testes. chlo. chloragoyven cells. 4 male pore. jp. penis. atr. & pr. prostate and 
atrium. pr. m. muscular layer of prostate. pr. g. glandular part of prostate. ar. atrium. sir. storage 
chamber for protozoa. spd. spermduct. int. intestine. br. bridge. 
