118 CALIFORNIA ACADKMY OF SCIENCKS. 



PLATE XLIII. 



ECHPIDKILUS FBIGIDUS. 



97A. Cross-sectiou of the neck of a uephridium. 



97B. Section of the long duct. 



97C. Nephrostome and part of duct. 



99A. Section of the lower part of the male organ, slightly oblique to the longitudinal axis of the penis, but parallel 

 to the atrium. air. atrium, f.l. fibrous tissue. in. inner lining of the atrium with long oval nuclei. 

 I. ms. longitudinal muscular layer of atrivim. (. irn. transverse muscular layer, ijl. small glands scattered 

 over the surface of atrium and prostate, sjid. spermduct. sep. part of the septum between x/xi. sphxt. cir- 

 cular muscles or sphinxter. ijl. c. large glandular cells composing the collar, m. p. muscular plates, to which 

 the longitudinal muscles of the atrium are joined, lube, penis tube. ps. penis sheath, pre. preputium. 

 hd. body-wall. 



99B. Section of inner penis tube of the former figure. 



100. The lower end of the male organ, atrium and prostate in somite x, xi, somewhat diagrammatically figured, in 



order to show the different layers, penis, etc. pr. prostate proper, projecting somewhat into x. s. septum. 

 t. pr. terminus of prostate. ;)r. m. muscular layer surrounding the prostate. This layer contains numer- 

 ous glands, pir. ijl. glandular layer of long flask-like cells. t'p>. inner lining epithelium, tube tube running 

 from prostate through penis and atrium — a penis lumen, with thick walls connected with the atrial wall by 

 numerous strands, which on the upper part form a thick layer surrounding the tube, but lower down becomes 

 thin, at least consisting of only few strands, cot. collar surrounding posterior part of penis, p. penis, 

 projective part. jtre. preputium, eversible. hd. body-wall. /. I. fibrous tissue. 



101. A somewhat larger view of the lower end of the penis. Both this and the former drawing are made from 



dissections mounted in gum-thus and viewed from above. Letters indicate the same as in fig. 92. 



