-222 Mr. H. B. Preston on new 



Long. 4-75, lat. 6-5 mm. 



JJab. Mullet Creek, Port Stanley, Falkland Islands 

 {A. G. Bennett). 



Cyamium copiosunij sp. n. (t'ig. 9-) 

 Shell moderately large, ovately cuneate, whitisli, bearinj^ 

 traces of having been covered with a thin, membranaceous, 

 dark cream-coloured periostracum ; both valves couceutri- 

 cally striate ; uuibones rather large, prominent ; dorsal 

 margin gently sloping; ventral margin scarcely rounded; 

 anterior side sloping above, rounded below ; posterior side 

 someu'liat produced, acumi'nately rounded ; right valve 

 bearing two erect cardinal teeth, of w-hich the anterior is 

 somewhat tiianguhir in shape and grooved down the centre, 

 •while the posterior is narrow and very slightly curved ; left 

 valve also bearing two cardinal teeth, of which the anterior 

 is moderately tine and obliquely placed, while the posterior 

 is broad, narrowly triangular, and abruptly terminating. 

 Long. 6, lat. 8"5 mm. 



Hah. Mullet Creek, Port Stanley, Falkland Islands 

 {A. 6r. Bennett). 



Cyamium cuneatum, sp. n. (Fig. 10.) 

 Shell ovately cuneate, whitish yellow, both valves in- 

 distinctly concentrically striate ; umbones moderately small, 

 slightly prominent ; dor.-al margin sloping ; ventral margin 

 very gently rounded ; anterior side abruptly sloping above, 

 nearly straightly descending below ; posterior side produced, 

 rounded ; anterior cardinal tooth in right valve moderately 

 coarse, obliquely triangular; posterior tooth in right valve 

 oblique, slightly curved, narrow above, slo])ing to a broad 

 base ; anterior cardinal tooth in left valve broad, triangular, 

 fitting belween the anterior and posterior in right valve; 

 posterior tooth somewhat weak and elongate, curved. 

 Long. 4'7o, lat. 6*5 mm. 

 Bab. Falkland Islands {A. G. Bennett), 



Cyamium stanleyense, sp. n. (Fig. 11.) 

 Shell differing from C. copiosum in its much more ovate 

 form ; the dorsal margin slopes considerably less and the 

 posterior side is obtusely rounded ; the valves are more 

 coarsely concentrically striate : the anterior cardinal tooth in 

 the left valve is much smaller ai:d the posterior is much 

 broader and coarser. 



Long. 5'75, lat. 9'25 mm. 



Hab. Port Stanley, Falkland Islands (A. G. Bennett). 



