Mr. T. R. Jones on some fossil Entomostraca. 27 



2. Candona reptans, Baird, Brit. Entom. p. 160. n. 2.tab. 19. 



fig. 3, 3 a. Length ^ inch. PI. III. fig. 7 a, b, c. 



Carapace oblong. Valves convex, glabrous, and in the recent 

 state green, and fringed at the extremities with hairs; nearly 

 straight on the dorsal, slightly sinuated on the ventral border ; 

 rounded posteriorly, and obliquely rounded anteriorly ; anterior 

 extremity slightly narrower and flatter than the posterior. 



Dorsal aspect elongate-acute-oval ; anterior suborbicular. 



Common in the recent state. Fossil at Newbury, Clacton, and 

 Grays : not rare. 



3. Candona torosa, nobis. Length g^y inch. PI. III. fig. 6 a, 



b, c, d, e. 



Carapace oblong, varying in length according to age. Valves 

 convex; bearing a marginal ridge at the anterior extremity; 

 bounded anteriorly and posteriorly ; straight on the ventral and 

 more or less arched on the dorsal border according to age, espe- 

 cially the right valve, which is smaller than the left and narrower 

 posteriorly. The surface of valves is marked with closely-set 

 pittings, coarse in the older specimens, and is raised in adult 

 specimens into 5-7 tubercles. Young specimens in general have 

 the surface almost even, or marked by a slight transverse sulcus 

 near the centre and just posterior to the lucid spots, which indi- 

 cate the position of the first-developed tubercle ; 3—4 tubercles 

 on the posterior moiety of the valve, and 1-3 smaller anteriorly 

 become apparent afterwards. Occasionally well-developed tuber- 

 cles are present even in very young specimens ; and on the other 

 hand individuals reach their full growth without being marked 

 with more than one anterior tubercle. 



The hinge is considerably developed, the hinge-margin of the 

 right valve bearing anterior and posterior sets of " knurlings," 

 which are received into corresponding furrows on the hinge- 

 margin of the opposite valve. 



Dorsal aspect irregular acute oval; anterior somewhat hexa- 

 gonal. 



This well-marked species occurs abundantly at Grays, and is 

 also plentiful in a living state in the Gravesend ditches. I have 

 to acknowledge Mr. Pickering's kindness in favouring me with 

 the recent specimens of this interesting species. 



3. Genus Cythere, MUller. 



Gen. Char. Animal creeping ; provided with two pairs of an- 

 tennae, — upper pair simple and setiferous, lower pair furnished 

 with a long filament, — and three pairs of feet. Inhabiting 

 fresh and salt water. 



