

1923.) Zoological Results of Expedition to Yunnan. 419 
Form distensa, nom. nov. 
1898. "Limnaeus auricular Jiinnanensis, Neumayr in hig: Szé- 
chenvy’s Reise in prphala iy II, p. 657, Plate XIV, Fig 
This form is not really related to L. ue ! from 
which the shell differs in the structure of the columellar fold. 
In ZL. auricularia the outline of this fold, broad above and 
very narrow below, is extremely characteristic. n my new 
form it is unifor mly narrow, The radula, moreover, and the 
genitalia are quite different. In particular the prostate is of 

Fig. 3. Genitalia cf Limnaea yunnanensis and distensa. 
m., retractor muscle of penis; p., penis; pr., prostate; p.s., penis- 
sack ; ie > Spermatheca 
a ditferent shape and the spermatheca has a shorter duct. 
[ figure the male part of the genital system and the sperma - 
theca from a sketch by Mr. Srinivasa ‘Rao. The radula in a 
specimen from the upper Salween system only differs from 
that of the type specimen of LZ. yunnanensis in that the ento- 
cone of the laterals is not so w ail developed. 
Specimens of this form, with others intermediate between 
it and the forma lypica, were taken both at Yung-Chang on the 
St ee Salween and in a raised beach near the north-west shore 
0 h-hai. 
Type-specimen. M 12453, Z.S.1. (Ind. Mus.) 
Family PLANORBIDAE. 
Gyraulus longios, sp. nov. 
1878. ? Planorbis compressus, Nevill in Anderson’s Zool. Anat. Res. 
Yunnan, p. 388. 
The shell is of a moderate size, very flat, with both sur- 
—- = hroadly and shallowly concave, witha distinct, mene umbili- 
: I The t two forms, indeed, niouns to different sections Fe Figs genus 
te ‘eelprsge to Radix Montfort and L. yunnanensis to Pseudosuccinea 
a&Ker. 

