114 The MoUuscan Family Planorhidae 



entocone cusps, a single raesocone, and three ectocone cusps, the mesocone 

 a trifle larger than the other cusps. Marginal teeth 7-cuspid (6, 8, 11, 12) 

 with three small cusps on each side of a mesocone cusp. There are no 

 intermediate teeth. The teeth are all in a straight row. They are very 

 uniform in size and shape but become narrower toward the outer edge 

 of the membrane. The teeth are essentially like those of Segmentina. 



For the above anatomical details a single specimen was dissected, 

 received from Dr. H. S. Rao, collected by Dr. N. Annandale in Inle Lake, 

 southern Shan States, Burma. 



Geographical Distribution. Known at present onlv from the tvpe 

 locality, He-Ho and Inle valleys (3000-3800 ft. alt.) southern Shan States, 

 Burma. Recent and fossil. 



Species Considered as Valid. Intha capitis Annandale is the only 

 species recognized for this monotypic genus. 



Remarks. Intha is peculiar in the form of its shell and also in the 

 characteristics of its genitalia, with the few prostate diverticula of large 

 size, the two enormous flagella, and the striking penial complex with a 

 penial gland which has a small, short duct entering the circular ring be- 

 tween the vergic sac and the preputium. In this respect it resembles some 

 of the Helisomatinae (typical Helisoma) but differs in the form of the 

 prostate and ovotestis. It appears to be another peculiar variant of the 

 Segnientina group of Planorbidae. 



Genus DREPANOTREMA Fischer and Crosse, 1880 



Monogenotype Planorbis yzabolensis C. and F. (= Pkinorbis anatinum d'Orbigny) 



1880. Drepanotrema Fischer and Crosse, Miss. Scient. Mex., Moll., II, pp. 59, 75. 

 Type Planorbis yzabalensis C. and F. As subgenus. 



1883. Drepanotrema Fischer, Man. de Conch., p. 509. Type Planorbis yzabalensis 



C. and F. As section of Planorbis. 



1884. Drepanotrema Tryox, S. and S. Conch., Ill, p. 107. Type Planorbis yzabalensis 



C. and F. As subgenus of Planorbis. 



1884. Bathijomphalus Tryon (non Agassiz, 1837), S. and S. Conch., Ill, p. 106. Pla- 



norbis anatinus Orb., cited as example. 

 1884. Ayiisus Tryon (non Studer, 1820), S. and S. Conch., Ill, p. 106. Planorbis 



kertnatoides Orb., cited as example. 

 1899. Drepanotrema M.artexs, Biol. Cent. Amer., Moll., p. 397. As synonym of 



Hippe litis. 



1899. Spiralina M.^rtexs, (part) op. cit., p. 395. Includes Drepanotrema cultratum 

 and sumichrasti. 



1899. Hippeutis Martens (non Agassiz, 1837), op. cit., p. 397. Cites Plaiiorbis yzabal- 

 ensis, type of Drepanotrema. 



1905. Drepanotrema D.\ll, Alaska Moll., p. 82. Type Planorbis yzabalensis C. and F. 

 As section of subgenus Hippeutis. 



1921. Drepanotrema Germain, Rec. Ind. Mus., XXI, p. 8. Type Planorbis yzabal- 

 ensis C. and F. As subgenus of Planorbis. 



1930. Drepanotrema H. B. Baker, Oc. Papers, Mus. Zool., Univ. Mich., No. 210, 



pp. 43, 38, 51. Type Planorbis yzabalensis C. and F. As genus. 



1931. Drepanotrema Thiele, Handbuch, Teil 2, p. 481. Type Drepanotrema yza- 



balensis C. and F. Section of Gyraulus, subgenus of Planorbis. 

 1934. Drepanotrema Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 58. Type Planorbis 

 yzabalensis C. and F. As genus. Figures genitalia of D. lucidum (Pfr.) and 



D. cultratum (Orb.). 



