NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSON. 901 



SPATHA DIVARICATA von Martens. 



* Spatha (livaricata \'ON Martens, l^escli., 1897, p. 250, pi. a'ii, fig. 15. 

 Lake Victoria; Nyanza. 



Subgenus MONCETIA Bourguignat, 1885. 



(Type, Moncetia aineiji Hourpfuig'nat. ) 



Shell long-elliptical, inequilateral, coir! pressed, thick, somber-colored; 

 beaks compressed, smooth, sharp; hinge with a tubcrc^nlar eminence 

 near the beak of the right valve, with two internal ligaments and three 

 groups of muscular impressions (Bourguignat).^ 



Animal unknown, 



SPATHA ANCEYI Bourguignat. 



* Moncetia anceyi Bourguignat, Esp. Ouk., 1885, ]). 34; * Icon. Mai., 1888, pi. xxx, 



fig. 1. — *voN Mautens, Besch., 1--91, p. 258. 



* Moncetia jouberti BovRGUiGfiAT Va. et Ir., 1886, p. 63; *lcon. Mai., 1888, pi. 



xxx, fig 4. 



Lake Tanganyika. 



SPATHA MONIETI Bourguignat. 



* Moncetia monieti Bourguignat, Uii. et Ir., 1886, p. 61; ''Icon. Mai., 1888, pi. 



xxx, fig. 7. 



* Moncetia rocheiraneana Bourguignat, Nonv. Mai., 1886, p. 62; "Icon. Mai., 



1888, pi. xxx, fig. 8. 



Lake Tanganyika. 



SPATHA LAVIGERINA Bourguignat. 



* Moncetia lavif/erina Bourguignat, Nouv. Mai., 1886, p. 60; * Icon. Mai., 1888, pi. 



xxx, fig. 6. 

 "" Moncetia hridomi Bourguignat, Un. et Ir., 1886, p. 65; *Icou. Mai., 1888, pi. 

 xxx, fig. 5. 



Lake Tanganyika. 



Subgenus ASPATHARIA Bourguignat, 1885. 

 (Type, Margaritana vignoniana Bernardi.) 



Shell elongated rhomboid, somewhat compressed, with a full, rounded 

 posterior ridge, from which curved rows of fine, broken corrugations 

 radiate; epidermis dark olive , wrinkled, rayless; beak sculpture not 

 seen; hinge with a low, slightly elevated ridge in the left valve in front 

 of the beak; dorsal scars small; nacre lurid, bluish-green. Animal 

 unknown. 



'This may be a distinct genus, though its characters seem to agree fairly well in 

 most respects with those of Spatha. Bourguignat does not describe the muscle scars 

 or tell anything of the nacre. 



