NO. 1205. SYNOPSIS OF THE NAIADES SLVFSOX. 807 



ADAMS, Gen. Rec. Moll., II, 1857, p. 497. *CHENU, Man., 1859, II, p. 142, tig. 

 700. * REEVE, Couch. Icon., XVI, 1865, pi. xxv, fig. 191. "HEUDE, Conch. 

 Fluv. Nank., II, 1877, pi. xvi, fig. 36.^ P.ETEL, Couch. Sam., Ill, 1890, p. 154. 



* Margarita ( Unio) grayainis LEA, Syn., 1838, p. 14. 



* Margaron ( Unio) yrayanus LEA, Syn., 1852, p. 21 ; 1870, p. 32. 



* Unio grayii GRIFFITH, Grif. Cnv., XII, 1834, pi. xxi, fig. 3. ' 



China. 



tNODULARIA GLADIOLUS Heude. 



* Unio gladiolus HEUDE, C. Fluv. Nauk., II, 1877, pi. xvi, fig. 35. V P.ETEL, Conch. 



Sam., Ill, 1890, p. 154. 



China. 



tNODULARIA TRIFORMIS Heude. 



* Unio triformis HEUDE, Couch. F. Nank., II, 1877, pi. xvi, fig. 34. 



" Unio dislorlus HEUDE, Conch. F. Xank., VIII, 1883, pi. LXII, figs. 122, 1226. 

 * PJETKL, C. Sam., Ill, 1890, p. 151. 



China. 



tNODULARIA OXYRHYNCHUS von Martens. 



* Unio oxyrhynchus VON MARTENS, Mai. Blatt, VII, 1861, p. 57. * KOBELT, Abh. 



Senok. Nat. Ges., XL, 1879, p. 420, pi. xin, figs. 3, 4. * PFEIFFER, Nov. Conch., 

 V, 1879, p. 192, pi. CLVII, figs. 4, 6. * P.ETEL, C. Sam., Ill, 1890, p. 162. * VON 

 IHERING, Abh. Senck. N. Ges., XVIII, 1893, p. 156. 



Japan. 



Section CYLINDRICA Simpson, 1900. 

 (Type, Nodularia cylindrica Simpson.) 



Shell inflated, solid, cylindrical, smooth, with a rounded posterior 

 ridge; teeth heavy, pseudocardinals radiate, curved. 



NODULARIA CYLINDRICA Simpson. 



* Unio grayanus SciiREXCK, 2 Reis. und Forsch. im Am. Lande, 1867, p. 694, pi. xxvn, 



figs. 1-3. 



Nodnlaria cylindrica SIMPSON, Pr. Ac. N. Sci. Phila., 1900, p. 84. 

 Amur land. 



Section NODULARIA Conrad, 1853. 

 (Type, Unio douglasicv Gray.) 

 Characters the same as the genus. 



(Group of Nodularia douglasue.} 



Shell olive to blackish, subsolid; surface generally more or less cov- 

 ered with nodules arranged in subradiating or chevron-shaped patterns. 



1 1 have seen a curious shell in the collection of Mr. Bryant Walker shaped some- 

 thing like the N. grayana, hut quite heavy and decidedly inflated in the post-basal 

 region. It may be an old grayana, but is so eroded that I can not be certain. 



'Schrenck supposes this to be the Unio grayanus of Lea, but it is very different. 

 It is a large, heavy, cylindrical shell, apparently without sculpture, and the figure 

 does not show plainly whether it has any posterior ridge. A large form between 

 grayanus and oxyrhynchus is found in Korea, according to von Martens, Sitzber. Nat. 

 Fr., 1885, p. 77. 



