720 MR. E. A. SMITH ON SHELLS FROM LAKE NYASSA. [NoV. 6, 



This species is remarkable for the subgranose plications on the 

 whorl?, and the brown carina of the body-whorl. It is difficult to 

 describe in a few words the colour of this interesting form. The 

 general appearance is livid, inclining to yellow or very pale olive ; 

 one shell is livid, with the upper margin of the whorls reddish. 

 The callous band is quite conspicuous only about halfway around 

 the body-whorl, and then gradually fades away, and is only noticeable 

 further up the spire by slightly obliterating the lower extremities of 

 the longitudinal ribs. 



Two not quite adult specimens were collected by Dr. Kirk at the 

 delta of the Zambesi River, and were placed in the British Museum 

 by Earl Russell. 



2. Natica antoni, Philippi. 



Natica antoni, Philippi, Zeitschrift fiir Malakozool. 1851, p. 48; 

 Kiister's Conch. Cab. p. 144, pi. 19. f. 18. 



Hab. Mouth of the Macusi River, near Qailimane, E. Africa. 



Nothing can be added to Philippi's excellent description of this 

 interesting species ; but I may mention that a young specimen has 

 a distinct pale zone around the middle of the last whorl, between 

 the two series of brown spots, which are more or less obsolete in 

 the adult shell, and that its umbilicus is quite filled up with the cal- 

 losity, even in the immature condition. The operculum is shelly, 

 white exteriorly, except near the nucleus, where there is a small pale 

 brownish callous deposit. The surface is smooth and shining, sculp- 

 tured with the lines of growth, and a single distinct striation parallel 

 with the outer edge, thus marking off a separate margin, From the 

 nucleus a short ridge or rib extends itself towards the centre. The 

 inner or under surface is clothed with a thin, pale yellow epidermis. 



3. Tellina opalina, Chemnitz. 



Tellina opalina, Chemnitz, Kiister's Conch. Cab. p. 172, pi. 35. f. 8. 



Tellinides rosea, Sowerby, Gren. Rec. and Foss. Shells, f. 1. 



Tellina planissima, Anton ; Philippi, Abbild. i. pi. 2. f. 2 ; The- 

 saurus Conch, f. 197; Conchol. Icon. pi. 13. f. 58 a, b. 



(Non T. opalina, Sowerby, Conch. Icon. sp. 258, f. 258 a, b.) 



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



Only a single specimen, which apparently belongs to this species, 

 was collected. It differs from the normal form in being rather more 

 equilateral. It is pale rose-colour, almost white at the umbones, 

 and at the ligamental area ; and the internal raised radiating ribs 

 are well defined. The name opalina, proposed by Sowerby for a 

 species in the collection of Mr. Hanley, must be changed should it 

 prove to be a well-defined species. 



4. Tivela dolabella, Sowerby. 



CythercBa dolnbella, Sowerby, Thesaurus Conch, iii. p. 619, pi. 

 127. f. 15 ; Reeve, Conch. Icon. xiv. sp. 2. 

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

 This species was originally described from a specimen in Cum- 



