CLOACA AND SPERMATII KCA OF GYRINOPHILUS. 



269 



thirds of the dorsal elevation in the adult. Moreover, the median 

 dorsal slit into which the common tube opens has deepened 

 slightly by the development of the folds which form the elevation. 

 As a result of this, as well as because of the further invasion of 

 the tubules and elongation of the common tube, the organ lies 

 farther from the dorsal wall of the cloaca in the third specimen 

 than in the first. 



Ventral glands are not altered in the n.o cm. animal. Of 

 the dorsal group, three are found on each side in their old position 

 caudal to the spermatheca. The latter are rudimentary; the 

 height of their development was apparently reached when the 

 spermatheca first appeared. They are exceedingly variable in 

 all adults as was noted previously. When present, they are 

 always located a short distance caudal to the spermatheca. 

 The ventral group, appearing at the same time, subsequently 

 become long, tortuous tubules with epithelium of the mucous 

 secreting type, and are the functional glands of the adult. 



The final changes in the spermatheca consist of its further 

 removal from the cloaca, the further bending of its tubules in a 

 caudal direction, and a change in form of the common tube. 

 By overgrowth of the dorsal wall caudal to the spermatheca, 

 the caudal or Y-shaped portion of the common tube is lifted 

 farther from the cloaca, loses its direct connection with the 

 cloaca, and communicates with it only by means of the cephalic, 

 unbranched portion of the common tube. Meanwhile, the 

 branches of the common tube are drawn ventrally, so that the 

 lumen of this portion of the tube, now most distal from the 

 opening, comes to resemble an H (Fig. 25). They are also bent 

 caudally, hence in their most distal (caudal) part, may be seen 

 isolated from each other (Fig. 24). The unbranched portion of 

 the common tube (formerly its cephalic portion), now consider- 

 ably enlarged, leads from the cloacal wall to the cross-bar of 

 the H, and to the two branches. This stage (Figs. 24, 25, and 

 26) is an intermediate one in development, and appears at 11.2 

 cm., but was also seen in one full sized adult of 14.5 cm. By 

 further expansion of the cross-bar of the H, the expanded end 

 of the adult common tube is formed; from this large chamber 

 its two branches extend caudally and somewhat ventrally. 

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