1330' SPATHA 



"This fori.i approaches the SpathcUa boitrgitignati Ancey, 

 but differs in its less elongated shape, the anterior margin is 

 oval and not elliptical, the posterior end is wider and much 

 less rostrated, the ventral margin is decidedly convex and 

 not oval elliptical, the beaks are more prominent and. finalh\ 

 by its larger size." 



Spatha MAiTKNGUENSis Sturany. 



"Shell elongate, quite regularly oval, dark brown with faint 

 olive-green bands. The dorsal margin of the right valve ex- 

 tends above the left principally in the umbonal region and an- 

 teriorly. The ventral margin is nearly straight, being only 

 very slightly incurved in the middle, the posterior portion hor- 

 izontal, scarcely ascending ; posterior extremity rounded. The 

 length of the shell is to the diameter as 2:1; the beaks are 

 situated in the first fourth of the length. 



Length 88, height 46, diam. 25 mm., the anterior end is 20 

 mm. long." (Sturany). 



Type locality, Maitengue River, Matabele Land. 

 Spatlia maitenguensis Sturany, Denk. Ak. Wien LX\'II, 1898,. 



p. 628, pi. Ill, fig. 66. 



"This new form is indeed closely related to Spatha 7\.'ahlbcrgi 

 var. dorsolis and Sp. ivahlbergi var. spatiiliformis, but can- 

 not be united to either and even less to typical Sp. zvahlbcrgi. 

 In order not to bring confusion into the synonymy. I have pro- 

 visionally separated it as a species." 



Spatiia lacustkis Simpson. 



Shell long obovate, subsolid, convex, inequilateral ; beaks 

 small, somewhat sharp ; posterior ridge rounded ; dorsal line 

 nearly straight; basal line lightly incurved in front of the 

 middle, full behind ; anterior end narrowed, rounded ; poste- 

 rior end rounded, slightly produced in the middle ; post-dorsal 

 region lightly winged, angular behind the ligament ; epidermis- 

 fuscous chestnut, pale at the beaks, dark and intensely colored 

 on the dorsal slope, where it is somewhat waxy and shining ;: 

 nacre pale rose. 



Length 98, height 52 mm. 



Lake Nvassa. 



