OF SOUTHEEN INDIA. 115 



3«. Fsammotella, Blainv., 1824. This includes a few yellowish or purplish 

 coloured species with a thin epidermis ; posteriorly slightly rostrated and rounded ; 

 the fulcrum is very strong, and the margin in front of the hinge somewhat 

 thickened, as if indicating a lateral tooth. The type of the sub-genus is Uiatula 

 ( SoletelUna) siib-radiata, Desh. 



35. FsammotcBci, Lamck., 1818, (Capsella, Desh. ; see Reeve in Conch. 

 Icon. x). Shell transversally elongated, thin, beaks slightly prominent, the posterior 

 side indistinctly ridged, scarcely less high than the anterior, sub-equilateral, 

 covered with an olivaceous epidermis ; hinge with one tooth in the left and two 

 in right valve, aU three short, blunt, and grooved ; paUial sinus deep. This includes 

 a number of eastern shells, in which the epidermis is strongly developed and 

 the shelly part thin ; they appear partially to live in brackish water ; Psammotcsa 

 Layardi, Desh., may be considered as the type. 



4. Sangiihiolaria, Lam., 1799. Shell largely oblong, thin, posteriorly 

 considerably attenuated and sub-angular; hinge with two approxiniate, partially 

 bifid teeth in each valve ; pallial sinus very wide, somewhat irregular. Reeve 

 describes five species, most of which are rose coloured. S. sangiiinolenta, 

 Gmelin, is the type of the genus; the shells are distinguished by their largely 

 oval and compressed form and their thin structure. 



5. EUzia, Gray, 1852. Shell compressed, thin, like Sanguinolaria, but sub- 

 orbicular in shape, and not ridged posteriorly ; the anterior side much shorter ; hino-e 

 with thi'ee teeth in the left and two in the right valve ; in the former the central 

 indistinctly bifid, and the posterior are in both almost horizontally prolongated. 

 Reeve describes two species as SoletelUna ( = Iliatnla), the well known E. orbi- 

 culata from Sumatra, and another,. E. recersa, from Malacca ; the latter seems 

 hardly to differ from the former. 



b. Sub.famili/,—TELLININJ!!, 

 In this sub-family are included the species which are by older concholoo-ists 

 usually called Tellina. The animals of these species have, as a rule, very lono-, 

 thin siphons with entire orifices, and the two plumes composing the gills anteriorly 

 grown together in one plane, but posteriorly more or less free, palpi very 

 large ; the shells are peculiarly attenuated and compressed posteriorly ; the surface 

 is very regularly concentrically striated, and in the larger number of them the 

 hinge is furnished with lateral teeth ; those of the left valve are, however, generally 

 smaller or even obsolete ; the posterior gape is always distinct, though narrow, 

 but the anterior is only occasionally traceable ; the ligament is strong, the fulcra 

 not very prominent, the pallial sinus usually very large. Their geographical 

 distribution is world-wide, and the first species occur in the Jurassic period ; 

 they are, as a rule, true marine shells. 



6. Macoma, Leach, 1819. Shell slightly inflated, or compressed, cardinal 

 teeth small, sometimes nearly obsolete, the laterals are, as a rule, not developed 

 at all, occasionally there is a thickening of the margins observable. The shells 



