168 The Molluscan Family Planorbidae 



The penial complex (fig. 12) consists of a very large, pyriform pre- 

 putium (PR), 3.5 mm. long and 2 mm. wide at the upper part, tapering 

 to 0.5 mm. wide at the male opening. The vergic sac (VS) is very small 

 (about 1 mm. long) and is placed at the summit of the preputium, lying on 

 that organ. There are two retractor muscles (RM), an upper one attached 

 to the preimtium near the vergic sac by two branches, one branch on each 

 side of the vergic sac, and a lower muscle attached at about midway of 

 the preputium. There are four or five sui)porting nuiscles (SM) on the 

 opposite side from the lower retractor muscle. In some specimens, the two 

 retractor muscles are placed one above the other attached to the preputium 

 near the upper part, with smaller muscles joining the two larger muscles 

 and a small muscle extending to the vas deferens (fig. 7, RM, VIM). This 

 form of musculature was more common than the one shown in fig. 12. The 

 vergic sac and a part of the vas deferens are attached to the surface of the 

 preputium, as shown in fig. 12. 



Internally (fig. 11), the large preputial cavity has two heavy, vertical 

 pilasters (PL). In the upper part of the preputium, there is a peculiarly 

 shaped penial gland (GL). It is shown somewhat restricted in fig. 11 and 

 drawn upward in the preputial sac. There is a conspicuous gland appendage 

 (GA). The verge (V) is very small (0.7 mm. long) and very narrow and is 

 attached to the vas deferens at about the apex of the preputial sac. When 

 fully extended, the penial gland has the form shown in fig. 1. The gland 

 becomes a rosette surrounding the opening into the vergic sac (X in figure) , 

 and the gland appendage (GA) extends forward (or downward) in the 

 preputial cavity, ending in two lateral swellings which notably resemble 

 the glans penis of the human genitalia. There is a narrow canal or channel 

 which extends down the center of the appendage for its entire length (C). 

 A cross section of the appendage indicating the ]X)sition of this canal is 

 shown in fig. 2 (C). 



The verge (highly magnified) is shown in fig. 6. It is short and narrow, 

 somewhat enlarged toward the lower end, with a centrally located sperm 

 canal and exit. There is a narrow vergic sac cavity ( VO) . The channel 

 which extends down the center of the penial gland appendage is seen to 

 extend upward and into the vergic sac cavity (C). There is a small penial 

 appendage beside the sperm canal outlet of the verge which is flattened 

 and extends diagonally from the end of the verge, as shown in fig. 8 (PA). 



Female Organs. The spermatheca (S) is large and pyriform in general 

 shape (fig. 13 », about 1.5 mm. long and 1 mm. wide. The duct (SO) is 

 2.5 mm. long and is a narrow tube. The vagina (VG) is narrow, a trifle 

 more than 1 mm. long and less than 0.5 mm. wide. The uterus (U) begins 

 with the same diameter as the vagina but rapidly enlarges to about 1 mm. 

 wide. It is about 8 mm. long. The nidamcntal gland (NG) is a large sac- 

 like organ 3.5 mm. long and about 2 mm. in diameter (see fig. 4, NG). The 

 oviduct (OD) is over 4 mm. long and is a large flattened tube about 

 0.5 mm. in diameter. There is a large carrefour ((5Fj. The albumen gland 

 (fig. 9) is squarish in shape and is composed of many small follicles. 



Hermaphrodite Organs (fig. 13). The ovotestis (OT) is very long and 

 occupies a little more than one whorl. It is composed of many diverticula 

 which form a pavement-like pattern on the surface of the ovotestis. In 

 section (fig. 5), the organ shows seven main diverticula each of which is 



