MUTEr,A r359i 



Beaks situated at 1-3 of the length; posterior angle at 4-5 to 

 5-6 of the length. 



Length 85, height at beaks 33. at wing t;j, diam. 22, from 

 the beaks to the end of the hinge 40 mm." (von Martens). 



Type locality, Lake \ ictoria-Nyanza. 

 Mutela honrguignali var. tnincato von Martens, Besch., 1897, 



p. 255, pi. VII, fig. 17. 



Group of Mutela rostrata. 



Shell somewhat inflated, thin, elongated, with a low^ round- 

 ed posterior ridge ending in a point about midway up from the 

 base ; beaks low, smooth ; epidermis bluish-green, rayless ; 

 hinge line edentulous or having only the faintest vestiges of 

 denticles ; muscle scars large, shallow, indistinct ; nacre bluish, 

 shaded violet. 



Animal the same as in typical Mutela. 



Mutp:la rostrata (Rang). 



Shell elongated, thin, convex, irregularly elliptical, inequi- 

 lateral ; beaks somewhat full, elongated, nearly or quite 

 smooth ; dorsal line straight ; basal line straight or slightly 

 curved ; anterior end regularly rounded or sometimes slightly 

 cut away below ; dorsal slope often feebly winged, obliquely 

 truncate ; posterior ridge well developed, narrowly rounded, 

 ending in a rather sharp point about on the median line ; sur- 

 face with fine, irregular, concentric sculpture and faint, radial 

 markings ; epidermis olive-green, usually dark ; muscle scars 

 shallow^ ; nacre bluish, tinted with violet, sometimes rosy-pur- 

 plish or salmon-tinted. 



Length 104, height 32.5, diam. 17 mm. 



Length 90, height 32.5, diam. 20 mm. 



Tropical Africa. 

 Iridina rostrata Rang, Nouv. Ann. Mus., 1835, P- 3^6. — Po- 



TTEz and Michaud, Call. Moll., 1844, p. 147, pi. lvi, fig. i. 

 Spatha rostrata von Martens, Mai. Bl., XIH, 1866, p. 11. 

 Mutela rostrata Jtckeu, Faun., 1874, p. 269. — Simpson, Svn., 



1900, p. 905. 



