. 
198 CALIFORNIA ACADEMY OF SCIENCES. 
PLATE LVII. 
ACANTHODRILUS VASLITI. 
148. The largest specimen, natural size, but not yet adult; the clitellum not developed. 
149. Anterior part of a young specimen; clitellum not developed. The nephridia and some other detail not figured. 
s. pl. sgl. subpharyngeal salivary gland. prc. ss. peritoneal cells forming solid masses, probably surrounding 
rudimentary sperm-sacs. prc. large peritoneal cells lining the septa as well as the peritoneum. a. p. pr. 
anterior pair of prostates opening close together. p. p. pr. posterior pair of prostates. 
150. Part of the ventral part of the body in somites xvii, xviii, xix laid open, showing prostates and thick septa 
with peritoneal cells. m. copulatory muscles. «a. pr. anterior prostate. p. pr. posterior prostate both of 
the same pair. 
151. Cross-section of the body-wall in somite xix, showing the prostate pore, and the two prostates opening close 
together. 
152. Section through the same pore, three or four sections further back, showing the tubercula spubertabe sense 
organ, ete. deb. debris. sup. c. supporting cells. 
153. Part of a septum, showing the very large peritoneal cells, some of which are broader, others longer and nar- 
rower. 
154. Cross-section of the two prostates. p. pr. posterior prostate pore. a. pr.anterior prostate pore. prt. perito- 
neal cells and connective tissue connecting the prostates with the body wall. 
PH@NICODRILUS TEPICENSIS. 
155. Spermathecs, side and front view of one and the same. 
156. Cross-section of the body in somite xvii through the male pore, showing the copulatory region with muscular 
atrium and spermduct. The longitudinal muscular layer is greatly increased at the male pore. The muscu- 
lar atrium is seen in cross-section, the cut passing through the whole length of that organ. This is also 
seen in figures 158, 159, the latter being taken from a section posterior to the former. 
157. The oviduct, ovisac and part of the ovaries, interior view of the body. 
158. Section through muscular atrium in cross-section of the body. The spermducts have not yet united, nor have 
they entered the atrium. The section passes through the whole length of the atrium. The arciform mus- 
cles must have been torn, as they did not show in the section. 
159. The same parts as seen in fig. 158, but four sections further back, the section passes through the outer layers 
of the atrium. The two spermducts have united and are entering the atrium in line with the longitudinal 
muscular layer. 
160. Arciform muscles around one of the male pores, viewed from the interior surface of the body. Only one side 
is shown. 
