558 MR. E. A. SMITH ON CYPR^A DECIPIENS AND [May 3, 



4. Note on Cyprcea decipiens. By Edgar A. Smith. 



[Eeceired March 23, 1881.] 



My description of Cypresa decipiens appeared in the Society's 

 ' Proceedino;s ' for 1880, p. 482. At that time only a single spe- 

 cimen was known, and that, unfortunately, in a worn and somewhat 

 bleached state. The British Museum has lately purchased two other 

 examples in most brilliant condition, brought home by the master of 

 a trading vessel from Port Walcot, North-west Australia. 



At the time of describing this species I pointed out several dis- 

 tinctions between it and the South-Australian C. thersites, which 

 differences are maintained in the two fine shells before me. These 

 are similar in size to the type figured (P. Z. S. 1880, pi. xlviii. figs. 8, 

 8 a), and present the same excessive dorsal humpiness; but their base is 

 scarcely so flattened, the outer lip especially being decidedly rounded. 

 The colour, too, appears to be variable. One specimen has the base 

 perfectly black ; and this colour extends up the sides almost halfway 

 to the vertex ; and the spotting on the back is much darker than ori- 

 ginally described. The second example is greyish brown or mouse- 

 colour at the base, becoming rather darker towards the teeth. The 

 former tint extends only a little way up the sides, and is varied with 

 a i&v! remote irregularly placed roundish dark spots. The upper or 

 dorsal region, however, is like that of its fellow example. The teeth 

 were stated to be about twenty in number ; but in these two shells 

 there are two more. The colour of the aperture far within is lilac ; 

 and the body-whorl within, beyond the teeth, is brownish white. 



It is most satisfactory to obtain two further specimens of a species 

 which, at first sight, so much resembles a dwarfed G. thersites ; for 

 they not only prove the stability of the species, but at the same 

 time confirm the judgment originally expressed as to its specific dis- 

 tinctness. 



t>. Descriptions of two new Species of Shells from Lake 

 Tanganyika. By Edgar A. Smith. 



[Eeceived April 16, 1881.] 



Mr. Damon, of "Weymouth, knowing the interest I have taken in 

 the shells of this lake, has kindly submitted to me for examination 

 a small collection which he recently obtained from this locality. 

 The two species about to be described are the only novelties. These, 

 however, possess much interest because of their relationship to the 

 genus Tiphohia. The opercula of the two forms are identical ; but 

 the character of the shells is so different that I am inclined to pro- 

 pose a new section, or subgenus, for the reception of the two new 

 ones. These in texture are solid, longitudinally costate and trans- 



