110 The Molluscau Family Planorhidae 



ANATOMICAL CHARACTERISTICS 

 PLATE 4 



GENITALIA. Male Organs (plate 4, fig. 9) . Seminal vesicle (SV) large, 

 tortuous, more than double the diameter of the ovisperm duct, with several 

 vesicles, but mostly tubular. Sperm duct, long (3.5 mm.), narrow. Prostate 

 (PRS) about 2 mm. long with twenty to twenty-two long diverticula. 

 Free portion of prostate duct very short. Vas deferens long (4 mm.) and 

 tubular. 



Penial complex (fig. 5) with a large, sac-like preputium (PR) and 

 small, narrow, short (little more than 0.5 mm.) vergic sac (VS). The 

 vergic sac is placed on the side of the upper part of the preputium. There 

 are two flagella, short and wide, placed on tube-like ducts longer than 

 the whole penial complex. The sac-like flagella (FL) are turned hori- 

 zontally to the tube-like duct. There is a very long and very fine, tube-like 

 external penial duct ( DC ) , about three times as long as the penial complex 

 when stretched to its fullest extent. There is a single, wide retractor 

 muscle (R]\I) attached about midway of the i:)reputium at the point where 

 the penial duct has its exit. 



Internally (plate 4, fig. 6) ,. there is a short, wide pilaster which bi- 

 furcates about midway of the preputial cavity, one branch forming a wide, 

 flat gland (GL) which is doubled backward at the end (fig. 6). The other 

 branch is short and narrow and ends above in a rounded, disc-like 

 organ (G). The very long duct (DC) which appears on the outside of the 

 preputium, enters a canal in this small branch (fig. 2, C, fig. 7, C) which 

 terminates on the underside of the reflexed end of the gland (fig. 7, GL). 

 Tlie other end of the penial duct passes on the outside of the small pilaster 

 and enters the round, turban-like termination of the small pilaster (figs. 

 2, 6, G and DC). There is a thickened muscular ring or diaphragm be- 

 tween the vergic space and the preputial space (figs. 6, 8, D). The retractor 

 muscle is attached to the preputium near the small liranch of the pilaster 

 (fig. 6, RM). 



The verge (fig. 8, V) is long and narrow, swollen or pear-shaped at the 

 upper part but narrowed and tubular below. The lower end of the verge 

 is notably flattened and broad, with a small penial papilla at the end, just 

 beside the sperm canal exit, which is in the center of the verge (figs. 3, 4). 

 The sac-like portion of the flagella is large and the cavity is lined with 

 elliptical cells which show on the exterior surface as small, rounded pro- 

 jections (fig. 5, PL). The duct of the flagellum is narrow but is of greater 

 diameter than the vas deferens. 



Female Organs, The spermatheca is globe-shaped (S) with a short, 

 narrow duct about as long as the greater diameter of the spermatheca 

 (SD). Another specimen had a spermatheca long and sac-like (fig. 5, plate 

 5) attached to the vagina by a very short wide duct. This spermatheca 

 contained a spermatophore and the specimen was evidently in gravid con- 

 dition. The form of the spermatheca evidently varies with the breeding 

 condition of the animal. Vagina rather short but longer than wide (VG). 

 Uterus (U) short and as narrow as the vagina. Nidamental gland (NG) 

 veiy long (3 mm.) and much swollen. Oviduct (OD) short and narrow. 

 Albumen gland ( fig. 1 ) elongated, about twice as wide as long, placed 

 over the stomach, the intestine looped beneath it. 



