XXX. CO'^CRYLIA—DITHYRA. 



2. punicea, valvd unidentatd cum laterali. 



the single toothed valve with a lateral tooth. 



3. Fabula, valvd alterd Icevi, altera obliquS striata. 



one valve smooth, the other striate obliijuely. 



4. similis, valvis oblique striatis. 



both valves striate obliquely. 



5. Donacina, latere antico obtusissimo. 



the anterior extremity very obtuse. 



6. bimaculata, ovato-trigona, maculata. 



oval-triangular, and spotted. 



7. depressa, ovato-oblonga, anticd rostrata. 



oval-oblong, produced to a point at the anterior 

 end. 



** valvis bidentatis, ovatcB. 



both valves with two teeth, and the shell oval. 



8. striata, valvd utrdque dentibus lateralibus. 



with lateral teeth in each valve. 



9. tenuis, valvd unicd dentibus lateralibus. 



with lateral teeth in one valve only. 

 *** valvis bidentatis, snborbiculares . 

 with two teeth in each valve, and the shell some- 

 what orbicular. 



10, maculata, valvd utrdque dentibus lateralibus.] 

 with lateral teeth in each valve. 



il. crassa, valvd unicd dentibus lateralibus. 



with lateral teeth in one valve only. 



