60 CALIFORNIA ACADEMY OF SCIENCES. 



63. luuer part of uephridinm more liighly magaitied. The numerals indicate the same places as in Fig. 59. The 

 letters are the same as in the above figure. 



fi4. Part of the same more highly magnified in order to show the capillaries and their connection with the inner 

 duct of the tube. I. f. tube leading to uephridio-stome. n. upper canal, h. lower canal, i.l. inuerlumen 

 of the duct which connects at c. with the capillaries, t. I. capillary tubes, longitudinal view. k. I. c. capil- 

 lary tubes seen in cross-section, sp. c. spongy canal or tube directly connecting with the duct 1 and con- 

 taining the capillaries, o. c. outer canal leading to the nephridio-pore. c. br. the narrow bridge connecting 

 the two main folds. /). c. point where ciliation begins. bl. r. blood-vessels, connecting with capillary 

 blood-vessels surrounding the two inner canals n and//; only a part of the blood-vessels are drawn. This 

 figure was carefully drawn with camera lucida, though, on account of the minuteness and numbers of the 

 ductules c. tr.. and i:. I., it was impossible to delineate all, almost one-fifth having been left otit in places where 

 they crowded each other. 



65. View of the spongy duct between 3 and 4 showing the inner canals « and h and the counecting ductules; 



letters indicate the same as in previous figures. 



66. The same spongy duct near 4, end view, and partly cross section. 



67. The posterior fold as seen at 5, the crosses -|- and X indicate the respective point corresponding on fig. 59, 



in order to show the direction of the tube, which is contrary to the one shown on hg. 59. sp. t. the spongy 

 tube with the iijiper and lower ducts, connected by ductules c. <. hi. bloodvessels, rap. capillary blood- 

 vessels, some of which surround the inner canals, others the outer fold. At the place marked with a X the 

 ductules begin to connect the upper spongy tube with the lower main canal instead of with the lower part 

 of the spongy tube, as at r. I. 



68. A somewhat larger figure of the last taken at the end X, where the lower part of the spongy tube has almost 



vanished and become bereft of its tubules c.l., capillary tubes entering canal 6. c. chambers on the central 

 canal in the spongy tube, which send off tubules on the other side of the two main canals, and which also 

 enter the canal, b. I. lumen of the spongy tube. In this and the previous figure will be seen how the tubules 

 of the spongy tube shown in figs. 65 and 66 have been found forming a more regular lumen I, which in the 

 next figure will be seen to emerge into or change to a regular canal. 



69. Part of the upper fold at 7, showing the tubules of the spongy tube to cease, the tube itself to become more 



regular, fusing itself in canal l>. The arrows show the direction of the fluid or excretions from the uepridio- 

 stome to the pore. 



70. Diagramatic section of the main fold at the place where the capillaries of the spongy mass have ceased, and at 



the very point of the outer band marked fig. 59 o. c.f. The spongy mass surrounding the canals is now void 

 of tubules. 



71. View of the anterior fold at 10, showing the inner ciliated canal — formerly the lumen of the spongy tube — 



and the two canals a and //, which are enclosed by a common glandular mass, a continuation of the spongy 

 tube. The lower fan-shaped lines are possibly openings or valves in the tube, connecting with the glandular 

 mass. As will be seen, the glandular mass is not continuous, but seemingly separated by lumens — I — which 

 may prove to be canals connecting with the tube at the slits above referred to. 



72. A part of same fold between 9 and 10. The lumen is here void of cilia, and the glandulous mass is smaller 

 7.3. The main fold as seen at the narrow place 9. I. lumen void of cilia, a. one of the canals n or b seen on the 



other side of the lumen, bl. v. bloodvessels surrounding the lumen and its glandular walls. 

 74A. Cross section of the posterior main fold taken at 3, before the main central lumen in the spongy duct was 



formed. 

 74B. Cross section of the posterior duct at 7, showing the blind ending of the tubules. 



75. A longitudinal section of the fold at 5, showing onlj' one of the central canals. 



76. The same, the under side of the lumen being in focus. 



77. A longitudinal section near 3 ; here also one of the canals has been cut away. 



78. Peritoneal cells of the nephridial supporting covering from /). c. fig. 59. 



79. The same, end view. p. c. masses of perigastric cells.. 



80. One of the perigastric cells more highly magnified. 



81. One of the spermatheca?, exterior view. 



82. Cross section of a spermatheca. a. upper sac-like part. b. lower muscular part. m. muscular layer of the 



sac-like part. I. m. longitudinal muscular layer of the body-wall. c. m. circular muscular layer of the 

 spermatheca. gl. ep. glandular epithelium. /. inner cavity of the spermatheca. .s/i. b. sperm balls. I. s. 

 lacunary system, or chambers for the storage of the spermatozoa, s. m. secreted mass with streaks of sperm- 

 atozoa. Kpz. spermatozoa, i. 7n. transverse muscular layer of the body-wall. spth. p. spermathecal-pore. 



S3. A longitudinal section of the spermatheca more highly magnified, showing the lacunary system and its position 

 to the epithelial cells. Letters as in the last figure. 



84. Cross section of the muscular part of the spermatheca, showing the arrangement of the storage chambers oc- 

 cupied by sperm balls. Letters as in fig. 83. 



