132 The Molluscan Family Planorbidae 



wide. The penial gland duct is short, as in scalare. There is usually more 

 of a constriction between the preputium and the vcrgic sac than in scalare. 

 Figure 8 shows an abnormal form of penial complex and fig. 12 shows 

 another in which the part of the preputial sac containing the i)enial gland 

 has been pushed upward. In fig. 9, this feature is still further emphasized. 



In Helisoma duriji (Wetherby), the preputial sac has been pushed up- 

 ward as in normale. In Heliso))ia duryi eudiscus Pilsbry, there is consider- 

 able variation. In fig. 1, the gland duct is swollen in a bilobed form, while 

 in fig. 2 it is very narrow. In fig. 7, the penial complex is very wide. Figure 

 5 shows the penial gland pushed upward in the lu-eputial sac. Figure 6 

 shows the wider penial complex in an immature specimen with a shell 6.5 

 mm. in diameter. In two specimens examined, the penial gland was ex- 

 tended from the male ojiening and lay outside on the neck of the animal 

 (fig. 13, duryi; fig. 16, H. d. normale). In fig. 16, it is shown just below the 

 female opening. 



The penial gland in the duryi complex is of about the same shape as 

 that organ in scalare. In H. d. eudiscus, the external form is shown in 

 fig. 4 and a section in fig. 3. There is the same division into an inner 

 and an outer cup as in scalare. In H. d. nortnale (fig. 10), a longitudinal 

 section shows the same features. In Helisoma duryi, the jienial gland is 

 short and wide. The gland of a half-grown specimen is siiown in fig. 19. 



The figures of the duryi complex agree with those by Pilsbry ( 1934, 

 p. 34, fig. 1, f, g, h, i, j, k). As Pilsbry remarks on page 36, the anatomical 

 differences are sufficient to separate scalare from duryi and its races. 



Respiratory and Renal Systems. The pseudohranch (plate 28, fig. 8) 

 is shoi't and wide (Pi. There- is a hirge cremilated ridge on the rectum iR) 

 which runs out on the jiseudobranch in a curve, to the right of the anal 

 opening (A). The pseudobranch is 1.5 nnu. long and about 1 nun. high. 

 It is contractile and its size varies greatly in preserved specimens. There 

 is a large pneumostome. 



The kidney (i)late 44, fig. 4) of .^c(dare is rather short (4 mm. long), 

 wider at the upper part near the ])cricardium (1 nnn. wide). The ureter is 

 directetl diagonally backward. The pericardium is al)out 1 mm. long. 

 A cross section of the kidney near the middle (fig. 25) shows a rather 

 long, narrow crest or ridge, a small ovate lumen and two small veins placed 

 just below the middle of the lumen. The small ridge in the mantle is shown 

 to the left in both figures. 



In H. d. normale (fig. 5), the kidney is longer (17 mm. long) and 

 comparatively narrower (3 mm.) than in scalare. The ureter is about 2 mm. 

 long and is bent backward against the lower part of the kidney. A cross 

 section of the kidney near the middle (fig. 26) shows it to be more com- 

 pressed than that of scalare, the crest or ridge bent more to the left but 

 of about the same form. The lumen is more elongated and about two and 

 one-half times as wide as high. The two veins are placed near the lower 

 border of the lumen. The kidney of Seminolina is more depressed than in 

 Helisoma and the lumen is comparatively larger. 



Digestive System, The stomach and intestine are as in Helisoma, as 

 are also the buccal sac and salivary glands. 



Jaw (plate 49, fig. 4, scalare; fig. 14, H. duryi normale) as in Helisoma, 

 the superior jaw with vertical striations on the inner face. 



