112 The Molluscan Family Planorhidae 



It is quite probable that other species belong in this genus and will be 

 discovered when examined anatomically. 



Mori ( 1938, p. 288) has called attention to the fact that this species is 

 a planorbid and not a land shell. He, however, places the species in the 

 genus Anisus, subgenus Hippeiitis, following the classification of Thiele. 

 The anatomy, especially the genitalia, indicates that this species can not 

 correctly be referred to either Anisus or Hippeutis, differing widely in its 

 internal organization. 



The genus is dedicated to Dr. Chi Ping, research professor in the Fan 

 Memorial Institute of Biology, Peiping, China, an accomplished student of 

 the Asiatic molluscan fauna. Dr. Ping has supplied the author with a num- 

 ber of mollusks for anatomical study from near Peiping. 



Genus IXTHA Annandale, 1922 



Type b}^ original designation Intha capitis Annandale 



1922. Intha Ann.^nd.^le, Rec. Ind. Mus., XXIV, p. 361. Type hitha capitis Annandale. 

 As genus. 



1931. Intha Thiele, Handbuch. Teil 2. p. 482. Anisus (I.) capitis (Annandale). As sub- 

 genus under genus Anisus. 



Shell. Tn this genus the body-whorl, though relatively smaller than it 

 is in Hippeutis, completely embraces- and occludes the rest of the shell in 

 such a way that the spire is entirely concealed, except in so far as it can 

 be detected by transparency. The shell is very minute and has few whorls, 

 which increase in size rapidly. Those of the spire are cylindrical, but the 

 body whorl is flattened below and has the form of a flattened conoid 

 slightly truncate above. The outer lip arises in the middle of the upper 

 surface and forms a small lobe at its point of origin. The aperture is large 

 and very oblique but with a cordate outline. There is a well-developed 

 simple callus on the inner lip, but internal ridges are completely absent. 

 The lower surface is narrowly umbilicate. The external surface is prac- 

 tically smooth' (Annandale, p. 361). The shell is ultradextral. No figure of 

 the shell is available and the single specimen used for dissection had the 

 shell badly broken which made it unfit for illustration. 



Animal. 'The animal is remarkable externally for the large upper and 

 lower lobes into which the mantle is divided. The pseudobranch is poorly 

 developed' (Annandale, p. 362). The head of the animal bears short, blunt 

 tentacles (plate 8, fig. 3). 



AXATOMICAL CHARACTERISTICS 

 PLATE 8 



GENITALIA. Male Organs (fig. 11). Seminal vesicle (SV) very large, 

 about three times the diameter of the ovisperm duct, with a few irregular, 

 pointed, glandular projections. It is less than 1 mm. long. Sperm duct 

 (SPD) long (slightly more than 1 mm.) and of large diameter. Prostate 

 short, with six large, club-shaped diverticula. Prostate duct (free portion) 

 about as long as the prostate. Vas deferens (VD) of small diameter and 

 very long (about 5 mm. when stretched out). 



The penial complex has a large, bulbous preputium (PR) and a small, 

 slender vergic sac (VS), somewhat shorter than the preputium (fig. 6). 

 Together both organs measure 1 mm. in length. There is a short, narrow 



