XXX. CONCHYLIA—DITHYRA. 



2. punicea, valvd unidentata cum laterali. 



the single toothed valve with a lateral tooth. 



3. Fabula, valvd altera Icevi, altera ohliquh striata. 



one valve smooth, tlie other striate obliquely. 



4. similis, valvis ohliquh striatis. 



both valves striate obliquely. 



5. Donacina, latere antico ohtusissimo. 



the anterior extremity very obtuse. 



6. bimaculata, ovato-trigona, maculata. 



oval-triangular, and spotted. 



7. depressa, ovato-oblonga, anlich rostrata. 



oval-oblong, produced to a point at the anterior 

 end. 



** valvis bidentatis, ovata. 



both valves with two teeth, and the shell oval. 



8. stiiata, valvd utruque dentibus lateralibus. 



■with lateral teeth in each valve, 



9. tenuis, valvd unicd dentibus lateralibus. 



with lateral teeth in one valve only. 



*** valvis bidentatis, suhorbiculures. 

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

 what orbicular. 



10. maculata, valvd utruque dentibus lateralibus. 



with lateral teeth in each valve. 



11. crassa, valid wiicd dentibus lateralibus. 



with lateral teeth in one valve only. 



