Subfatnilies, Genera, and Subgenera — Recent and Fossil 111 



Hermaphrodite Organs. The ovotestis (OT) consists of many long and 

 narrow diverticula placetl in a double series. The ovisperni duct (SO) is 

 of small diameter. The portion between the seminal vesicle and the ovo- 

 testis is very short (less than 1 mm.) but the portion between the seminal 

 vesicle and the oviduct is very long (about 3 mm.). 



An egg capsule on one of the shells, presumably of this species, con- 

 tained eight eggs. 



Respiratory and Renal Systems. The pseudobranch (plate 5, fig. 1, P) 

 is small and inconsjncuous, resembling that of Hippenfis. 



Tiie kidney is long and narrow, resembling that of Segmentina, but not 

 as long. The ureter is directed horizontally into the mantle cavity, not 

 reflected. There is no superposed ridge. A section of the kidney near the 

 middle shows a wide and low lumen about three times as wide as high 

 with the veins at the upper corners. A section below the middle shows a 

 flatter form with the lumen almost as high as wide and somewhat tri- 

 angular, the veins at the upper part of the triangle. This triangular form 

 is caused by the acute angle of the shell on the periphery. 



Digestive System. The stomach is long and narrow as in Segmentina, 

 the intestine making a loop around the stomach and another around the 

 liver and then passing forward to the rectum and pseudobranch. The blind 

 sac is very short and pointed below. 



The buccal sac is elongated, pear-shaped, the radula sac large and near 

 the middle of the posterior end. The salivary glands extend considerably 

 beyond the rear end of the buccal sac and are united behind; the ducts 

 are small and tube-like. 



The jaw is fragmented with about eighty plates. It is horseshoe-shaped 

 as in the other groups of this subfamilv. 



Radula formula 26-1-26 with 160-170 rows of teeth. The teeth resemble 

 those of Segmentina and Polypijlis (see j^late 69, figs. 7, 8). The laterals 

 have six short, spade-shaped cusps and the marginals have seven 

 short cusps. 



The anatomical details have been obtained from three specimens 

 from Peiping, China, received from the Fan Memorial Institute of Peiping, 

 through the courtesy of Dr. Chi Ping. 



Geographical Distribution. Northern and eastern China and Japan. It 

 is probable that this distribution will be extended when more material has 

 been examined from China and India. 



Geological Distribution. Unknown. 



Species Considered as Valid. Pingiella peipinensis (Ping and Yen), 

 the genotype, is the only representative of this monotypic genus. 



Remarks. This genus is remarkable for the peculiar characteristics of 

 the penial comj^lex, the penial gland, bifurcated into a large and a small 

 branch, the latter with a turban-shaped termination, and the very long, 

 tube-like external duct with its peculiar gland terminations. The terminal 

 end of the verge is also peculiar. The flagella are notable in having the long 

 ducts and the small, sac-like glands. These differences are sufficient to 

 stamp the species as belonging to a new and hitherto unknown generic 

 group. It differs from Segmentina in the possession of an external duct 

 and from Polypylis by having a penial gland which is absent in that genus. 



