Mollusc t from C'^ntrtil Africa. Oli 



Uah. Kaionga, northern eiul of Lake Nyassa {^Igr. Le- 

 choptois) . 



1 have before nic a good aeries of tliis shell, the largest 

 specimen nieasiuin^j; 42*5 hy 07 nun. 



Spatlia approxivians , sp. n. (Fig. 14.) 



Shell closely allied to S. tii/assensi's, Lea*, hut hroader 

 posteriorly, more aeiuninate, and covered with a perio-stracuin 

 nuich paler in colour ; the interior of the shell is exceedingly 

 finely granulate. 



Long. 64, hit. 100 mm. 



Hub. Shiie River, at a point from 3 to 4 kilometres to the 

 south of Lake Nyassa {Mgr. Lechaptois). 



Spatha bertilloniana, sp. n. (Fig. 15.) 



Shell moderately flat, rectangularly ovate, solid, scarcely 

 angled posteriorly, covered with a fine reddish-chestnut peri- 

 ostracum, sculptured with coarse, broad, somewhat distant, 

 concentric growtii-lines and very fine, transverse, radiate 

 strife ; umbones small, not prominent ; dorsal margin nearly 

 straight, somewhat ascending ; ventral margin constricted 

 towards the middle ; anterior side squarely rounded ; })oste- 

 rior side broadly produced, bluntly acuminate; anterior 

 adductor scars ovate, well impressed ; posterior adductor scars 

 broadly ovate, moderately impressed ; infra-umbonal visceral 

 scar in right valve broad, in left valve small, short, and deep ; 

 palleal margin coarsely defined; interior of shell nacreous, 

 pinki^h white, iridescent, especially towards the posterior side, 

 .sculptured with fine, interlacing, irregular, wavy striae con- 

 verging towards the centre of the shell. 



Long. 51"5, lat. 97 mm. 



Uab. Karonga, north end of Lake Nyassa. 



A very handsome species, of which the internal sculpture 

 is most curious and may, in a measure, be compared to the 

 markings of finger-prints ; in the single specimen before me 

 this remarkable sculpture is much more apparent in the right 

 than in the left valve. 



EXl'LANATION OF THE PL.\TES. 



Plate IV. 



7'iV/. 1. Heltcarion pfrf)a(/i/ts, sp. l^. 



Fig. 2. T/iapsia gervti, sp. n. 



Fig. 3. Subulina maringoensis, sp. n. 



♦ I'roo. Zool. Soc. London, 1877, p. 71!'. 



