Subjamilies, Genera, and Subgenera — Recent and Fossil 105 



cavity from the vcrgic cavity. The verge (.^^) is long (0.7 mm.) and very 

 narrow, tube-like and at the end there is a fleshy papilla and the sperm 

 canal has its outlet at the side of the verge just above this papilla (plate 

 5, fig. 6) . There is no penial gland in the penial complex. 



Female Organs (plate 5, fig. 7). The spermatheca (S) is rather small 

 and is attached to the long and narrow vagina by a narrow duct (SD) 

 about 1 mm. long. The vagina rapidly enlarges from its external opening 

 to the point of juncture of the spermathecal duct (VG). The uterus (U) 

 is not much longer than the vagina. The nidamental gland is long (2 mm.) 

 and much swollen (XG). The oviduct (OD) is short (1 mm. long) and of 

 about the same diameter as the uterus. There is a large carrefour (CF). 

 The albumen gland is large (1.7 mm. long) and ovate in outline (fig. 2). 



Hermaphrodite Organs. The ovotestis (fig. 7, OT) consists of many 

 very long and club-shaped diverticula placed in a double series. As many 

 as thirty-eight pairs of diverticula were counted in one specimen. The 

 ovisperm duct (SO) is very short between the ovotestis and seminal 

 vesicle and very long (2.5 mm.) between the seminal vesicle and the 

 oviduct. 



Respiratory and Renal Systems. The pseudobranch (plate 5, fig. 3) is 

 long and narrow and soniewliat folded, squarely truncated at the lower 

 margin. There is a large pneumostome. 



The kidney of Polypylis hemisphaerula is very long (7 mm.) and 

 narrow. It resembles the kidney of Polypylis calathus (plate 47, fig. 24) 

 which is long and narrow and 9 mm. in length. A cross section is similar 

 to that of calathus (plate 47, fig. 25) which shows the kidney to be flat- 

 tened, without a ridge, the lumen oval, wider than high with the two 

 lateral veins of large diameter. In hemisphaerula the lumen is rounder and 

 the veins relatively smaller. In outline the section of hemisphaenda more 

 nearly resembles that of Segmentina nitida (plate 47, fig. 23) than that 

 of calathus. 



Digestive System. The stomach I'esembles that of Segmentina nitida 

 (plate 48. fig. 16 1 but the blind sac is somewhat larger. The buccal sac 

 is pyriform. with a large radula sac behind and two small salivary glands 

 like those in Segmentina nitida. 



The jaw is like that of Segmentina nitida, segmented with many plates 

 (plate 50, fig. 24). Polypylis calathics has a similar jaw with many small 

 plates. 



The radula formula of hemisphaerula is 25-1-25 with over 200 rows of 

 teeth. The teeth are like those of Polypylis calathus (plate 69. fig. 8). all 

 6-cuspid. the cusps short and the reflections wide and low and placed high 

 up on the teeth. In calathus the formula is 26-1-1-26 with 205 to 210 rows 

 of teeth. The rows of teeth are all in straight lines, as in Segmentina. 



The above anatomical details were obtained from the following material: 

 Polypylu hemisphaerula (Benson) from Peipino;, China, sent by the Fan Memorial 



Institute, Peiping, China. Four specimens. 

 Polypyli.s calathu.'i (Benson), from weedv tank near inspection bungalow, Mongyai. X. 



Shan States, Burma. Collected by "Dr. H. S. Rao and Mr. B. H. Chopus. One 



specimen e.xamined. 

 Polypylis tnia (Annandale and Rao), from below Machligaon. Port Blaie, Andamans. 



Collected by Dr. H. S. Rao. One specimen examined. 



