1877.] MR. E. V. SMITH ON SHELLS FROM LAKE NYASSA. 719 



23. Unio nyassaensis. Lea. 



Unio nyassaensis. Lea, Proc. Acad. Nat. Sci. Philad. 1864, p. 108 ; 

 Journ. Acad. Nat. Sci. Philad. (1866), vol. vi. p. 33, pi. 12. f. 32. 



U. nyassce, Sowerby, Conch. Icon. sp. 224, f. 224, a, b. 



U. nyassensis. Lea, Sowerb. op. cit. Errata and Index. 



Var.= C7. kirhii. Lea, I. c. p. 108 ; Journal, p. 32, pi. 12. f. 30. 



Var. = ?7. aferula, Lea, /. c. p. 109 ; Journal, p. 34, pi. 13. f. 34. 



Hab. Lake Nyassa {Dr. Kirk). 



This species, like many others of this genus, is subject to con- 

 siderable variation in form and sculpture. The three forms de- 

 scribed by Lea are evidently nothing more than mere varieties of 

 one and the same shell. 



24. Spatha alata. Lea. 



Spatha alata. Lea, Proc. Acad. Nat. Sci. Philad. 1864, p. 109 ; 

 Journ. Acad. Nat. Sci. (1866) vol. vi. p. 35, pi. 12. f. 31. 

 Hah. Lake Nyassa {Dr. Kirk). 



25. Spatha nyassaensis. Lea. 



Spatha nyassaensis, Lea, I. c. p. 109 ; Journal Acad. Nat. Sci. 

 Philad. p. 36, pi. 13. f. 33. 

 Hab. Same as the preceding. 



II. Marine Species. 



1. Bullia mozambicensis, sp. nov. (Plate LXXV. fig. 18.) 



Shell elongate, acuminately spired, more or less livid in colour ; 

 whorls nine, the two apical ones smooth and shining, the rest but 

 slightly convex, separated by an oblique suture, sculptured with 

 oblique, somewhat flexuous, fine and close-set plicae, which extend 

 from suture to suture in the upper whorls, and gradually become 

 obsolete about the middle of the last volution ; these riblets or 

 plications, which are about equal in thickness to the spaces 

 between them, give the upper margins of the whorls a finely crenu- 

 lated appearance, and are subgranulous, through being intersected 

 by spiral striae, which gradually become wider apart as the shell 

 increases ; they are about nine in number on the penultimate whorl ; 

 the last is encircled by about 13; and the keel which winds 

 around its base is of a brown colour, and the portion of the 

 whorl below it whitish ; mouth ovate-acuminate above, occupying 

 a little more than | of the entire length of the shell, olive-brown 

 or purplish-brown margined with white within the labrum and at 

 the base ; labrum thickened, acute at the edge, and inconspicuously 

 sinuated above ; columella arcuate in the middle, thinly coated 

 with a white enamel, which, extending above the lip and winding 

 along the suture, gradually vanishes as it proceeds up the spire. 



Length 32 millims. ; diam. of last whorl 1 1 ; length of mouth 

 12^, width nearly 6. Operculum unguiculate, concentrically and 

 transversely striated. 



Hab. Mouth of the Macusi River, Quilimane, E. Africa. 



47* 



