1899.] NATURAL SCIENCES OF PHILADELPHIA. 367 



enormously distended when containing young, two of which occupy 

 it at a time. 



Albumen gland (figs. 5, 5a, a. gl.) very gmall, shorter than the 

 talon and far smaller than the spermatheca. Median moiety of 

 the hermaphrodite duct extravagantly convoluted and knotted. 



Vivipaz'ous; the shell of the young at birth is nearly one-fourth 

 the length, and exceeds one-third the diameter of adult shells, 

 with half the number of whorls. 



Jletractor muscle system (PI. XVI, fig. 9) somewhat resem- 

 bling that of Rumin.a ; right, left and tail retractors free except at 

 the very insertion, where they are very shortly united. Tail 

 retractor very long; right retractor splitting up distal) y into (1) 

 numerous anterior and lateral pedal retractors, (2) the retractor 

 of the eye, and (3) the retractor of the penis; left retractor giving 

 rise (1) far anteriorly to the short pharyngeal retractor which is 

 shortly bifurcate anteriorly, and (2) in front of this, splitting into 

 ocular and pedal retractors. 



Lung (PI. XVI, fig. 14) long and narrow, the venation faint, 

 mainly concentrated anteriorly and consisting chiefly of fine parallel 

 veins transverse to the pulmonary vein, which is otherwise un- 

 branched. Heart normal. Kidney more than double the length 

 of the pericardium, quite narrow, its length contained about 3^ 

 times in that of the lung. Ureter retrograde, continued along the 

 gut, closed throughout. 



The jaw (PI. XV, fig. 4) is arcuate, densely striated, under 

 strong magnification showing transverse striolation in its substance, 

 crenulatiug the vertical striae. 



Radula composed of 44, 1, 44 teeth in slightly bow-shaped ro^vs 

 (PI. XV, fig. 1). Centrals very narrow, less than one-fourth 

 ihe width of the adjacent laterals, and bearing no cusps in adult 

 animals. Laterals with the basal plate wide and square, tricuspid, 

 the median cusp broadly conic, not as long as the basal plate, side 

 cusps short and blunt. Marginal teeth with longer and blunt 

 cutting points on the median, and more acute cutting points on 

 the side cusps. 



Salivary glands united above. Crop moderately swollen, 

 stomach small, globose. 



Type iV. \_Herix] cakarea Born. Distribution, Brazil and 

 upper Amazon drainage. 



