188 



terior (inferior), pergracilis, humilis, posterior pervalidus; 

 dentes laterales elongati, subrectilinei, in utraque valva duo, 

 inferior validior et longior, transverse rugulosus, superior 

 brevior, granulosus, in valva dextra tertius infimus gracilis 

 laevis; impressio muscularis antica longior quam alta, rugosa 

 et cristula longitudinali 1 — 2 munita; accessoria parva, sim- 

 plex, longitudinaliter trigono-ovata. 



a) Long. 97, alt. 65, crass. 30, long, dentium latera- 

 lium 38 Mill. ; vertices in i j h long. siti. 



b) Long. 130, alt. 78, crass. 48, long. 53 Mill. 



a) nach einem kleinen wohlerhaltenen, b) nach grösseren 

 stark abgeriebenen Stücken. 



Siangkiang-Fluss, F. v. Richthofen. 



8. Unio retortus sp. n. 



v. Martens a. a. O. S. 4. 



Testa elongato-triangularis, crassa, cömpressa concen- 

 trice striatula, periostraco nigricante induta, antice brevis- 

 sima, postice rostrata rostro (ad dextram) retorto; um- 

 bones tumidi, prominentes; margo dorsalis anterior sub- 

 nullus, posterior longissimus, aequaliter sensim descendens, 

 margo ventralis subrectus, antrorsum arcuatim ascendens; 

 dens cardinalis valvae dextrae unicus, crassus, trigonus, sul- 

 catus; dentes laterales valvae dextrae duo, elongati, superior 

 validus, compressus, coriaceo- asper ulus, inferior brevior, 

 multo debilior; impressio muscularis antica profunda, rotun- 

 dato-trigona, sulculosa, accessoria parva, arciformis. 



Long. 96, alt. 41, crass. ad umbones 26 Mill.; vertices 

 in i/ 10 long. dent. lat. 42 Mill. 



Im Siangrkianff. 



Literatur. 



Proceedings of the Zoological Society of London 1873. 

 Part. I. III. (S. Malak. Bl. 1874. S. 83—89.) 



7. Jan. Beschreibung von neuen Arten von Achati- 



