92 The Molluscan Family Planorhidae 



The above description agrees substantially with that of Pilsbry (1934, 

 p. 55). The spermathecal duct in the specimens examined was not short, as 

 Pilsbry found it, and, therefore, the spermatheca was not really adnate. 

 The vergic sac, also, is almost as long as the preputium in the specimens 

 examined. With these exceptions the genitalia of glabratus {guadalou- 

 pensis) here figured are like the figures of the race christopherensis given by 

 Pilsbry on page 57. The figure by Scott (1940, p. 10) agrees with the 

 specimens personally dissected, especially in the form of the spermatheca. 



Respiratory and Renal Systems. The pseudobranch is rather long and 

 rounded. A frilled crest or ridge extends down the center of the rectum (R) 

 which it crosses as a simple ridge to the anal opening (A) and extends 

 across the pseudobranch to the lower edge. There is a large pneumo- 

 stome (PS). 



The kidney (plate 45, fig. 1) is long and narrow (16 mm. long, 2.5 mm. 

 wide). The ureter is nearly 2 mm. long and is a narrow tube directed 

 upward at a right angle from the kidney. The veins are very large. The 

 pericardium is 3 mm. long and 2 ram. wide. A low, wide ridge extends from 

 below the pericardium to the lower end of the kidney. 



Cross sections show several .interesting features. The position of each 

 section is shown at A, B, C, D, E, in fig. 1. Section E (fig. 7) through the 

 pericardium shows a large lumen nearly filling the entire section, con- 

 taining many glandular diverticula. There are no veins. In section D (fig. 

 8) the lumen is smaller, rather squarish in shape, with the pulmonary vein 

 (AP), large and round, on one side and the renal vein (RA), smaller and 

 oviform, on the other side. The low ridge is seen at the left. In section C 

 (fig. 9) the lumen is somewhat smaller and there is the same disparity in 

 size between the two veins. The ridge (RK), though wide, is higher than 

 in section D. In section B (fig. 10) the lumen is much smaller, the veins 

 still disproportionate in size and the ridge very wide, but low, and pro- 

 jecting over the left margin. In section A (fig. 11) near the base of the 

 kidney, the whole organ is seen to be flattened, the lumen very small, the 

 veins flattened, more nearly equal, and the ridge wide, flattened, and pro- 

 jecting over the left margin. The form of the long ridge to the left of the 

 kidney is shown at the left in this section (RD). The ridge is a very 

 characteristic feature in the kidney of Australorbis . 



Digestive System. The stomach region (plate 48, figs. 9, 10) resembles 

 that of Promenetus, the gizzard rather rounded, not flattened, the pyloris 

 long and the blind sac rather short and placed as in Helisoma. The intes- 

 tine makes a loop around the stomach and another looji around the liver, 

 then runs forward to the rectum which bears a plaited crest or ridge (plate 

 48, fig. 9). 



The buccal sac is short and high, not much elongated. The radula sac 

 or pouch is large and rounded, somewhat as in Tropicorbis. The salivary 

 glands are narrow and nearly three times as long as the buccal sac. They 

 are joined behind as in Helisoma. 



Jaws three in number as in Tropicorbis (plate 50, fig. 13). The superior 

 jaw is very high, the length being about three times the height. It is finely 

 striated on its anterior face. The side jaws are much shorter than the 

 width of the superior jaw and are very narrow. The side jaws are shorter 

 in comparison with the length of the superior jaw than in most species 



