187 



umbones tumidi, subapicales; facies ventralis angulo obtuso 

 a lateralibus distincta, medio inflexa, ante inflexionem fusce- 

 scens, subpilosa, margine labiiformiter prominente; margine 

 dorsali usque ad 2 / 5 longitudinis ascendente, dein arcuatim 

 descendente alam mediocrem compressam formante. 

 Long. 24, alt. incl. ala 12, crass. 10 Mill. 



» "-*-? n n » "i n " » 



Tungting-See im mittleren China, F. v. Richthofen. 

 5. Cristaria megadesma sp. n. 



v. Martens a. a. O. S. 3. 



Testa trigono-oblonga, tumida, magna, solida, con- 

 centrice rugosa, albida, periostraco nigricanti-brunneo induta, 

 intus pallide carnea; margo dorsalis anticus valde descen- 

 dens, posticus primum sensim descendens, dein subexca- 

 vatus, in rostrum biangulatum, perpendiculariter truncatum 

 abiens; margo ventralis antrorsum valde, postrorsum non 

 ascendens; umbones prominentes, carina obtusa obliqua in 

 angulum inferiorem rostri decurrente insignes; ligamentum 

 breve, crassissimum; in cardine utriusque valvae protu- 

 berantia parva loco dentium cardinalium, dentes laterales 

 breves, non ultra ligamentum producti, validiusculi , in v. 

 sinistra duo. 



Long. 146, alt. 96, crass. 68. Vertices in 3 / 10 long. siti. 



Ligamenti long. 34, crass. 13 Mill. 



Poyang-See im mittleren China, F. v. Richthofen. 



7. Unio Richthofeni sp. n. 

 v. Martens a. a. 0. S. 3. 



Testa ovato-lanceolata, valde compressa, crassa, con- 

 centrice striata et verrucis complanatis plus niinusve ex- 

 pressis sculpta, periostraco nigricanti-fusco, sericeo-nitente ; 

 pars antica brevissima valde attenuata; margo dorsalis 

 posterior alam altiusculam, rotundatam formans, ventralis 

 posterior valde arcuatus, extremitas postica rotundato-pro- 

 ducta; dentes cardinales horizontales, in valva dextra 

 unicus, sat crassus, subcompressus, in v. sinistra duo, an- 



