392 Zoological Society : — 



elongate, more compressed, and not so rounded. The carapace is of 

 a uniform yellow horn-colour, thin, and translucent. Ribs numerous, 

 elevated, rather narrow, about twenty-seven in number, with the in- 

 terstices marked with shallow pits and extremely fine punctations. 



This species approaches somewhat to E. brasiliensis, but differs 

 in the position of the umbones, those of E. Dunkeri being further 

 from the anterior extremity. The relative size of anterior and poste- 

 rior extremities differs also, the former in E. brasiliensis being much 

 broader than in the present species. It is a larger species also than 

 E. brasiliensis. 



Length of carapace, 7 lines ; breadth at umbo, 4 lines. 



Hab. Zimapan, Mexico ; in fresh water (Dr. Bunker). Com- 

 muuicated by T. R. Jones, Esq. (Mus. Brit.) 



3. Estheria Lofti, Baird. ~ 



Carapace of a very t light amber-colour, oval, rather swollen. Um- 

 bones very prominent, elongate, placed near the anterior extremity. 

 Dorsal margin slightly sloping. Ventral margin rounded. Anterior 

 extremity swollen, rounded, and broader than the posterior, which 

 is rather narrow, and somewhat compressed. Ribs of carapace few, 

 broad ; interstices marked with coarse-looking, raised, flexuous lines. 



This species resembles in form the E. tetracera as represented by 

 Krynicki, and found by him near Moscow and at Charkow, Russia. 



Length of carapace, rather more than 4 lines ; breadth at umbo, 

 3 lines. 



Hab. Stagnant water on the banks of the Tigris, near Bagdad. 

 Collected, along with E. dahalacensis, by the late W. R. Loftus, 

 Esq., in May 1855. {Mm. Brit.) 



4. Estheria Rubidgei, Baird. 



Carapace-valves ovate. Dorsal margin long, straight. Umbones 

 small, placed near the anterior extremity. Ventral margin slightly 

 rounded. Anterior extremity rounded. Posterior extremity emar- 

 ginate at upper part, giving it somewhat the appearance of the shell 

 of an Avicida. Anterior extremity rather the larger. Ribs of cara- 

 pace not numerous, and wide apart, the surface in the interspaces 

 marked with coarse and flexuously disposed raised lines. 



This species partakes of the characters of straight-dorsal-margined 

 species, E. dahalacensis and E. Macgillivrayi. From the last spe- 

 cies it differs in size, form of posterior extremity, and markings of 

 interspaces between the ribs, as well as their comparative size and 

 number, those of the present species being fewer and wider apart. 



Length of carapace, about 3| lines ; breadth at umbo, 2 lines. 



Hab. A dried-up "vley" near Port Elizabeth, Cape Colony. 

 Collected by Dr. Rubidge, and communicated to Henry Woodward, 

 Esq., by W. S. M. D'Urban, Esq. (Mus. Brit.) 



5. Estheria Macgillivrayi, Baird. ; 



Carapace-valves ovate. Dorsal margin long, straight. Umbones 

 small, placed about 1 line from the anterior extremity. Ventral 



