GENERA OF SHELLS. 21 



losa, virgata, staurella, crucigera, Spengleri, rostrata, lati- 

 rostra, sulphurea, foliacea, operculata, rosea, chloroleuca, 

 elliptica, albinella, margaritina, strigosa, planata, punicea, 

 depressa, pulchella, fabula, tenuis, exilis, donacina, nitida, 

 scalaris, psammotella, alternata, punicea, polita, iris, 

 tenera, intastriata, lateralis, decora. 



(b. orbicular or round-oval.) T. remies, sulcata, striatula, 

 scobinata, crassa, Ia3yigata ; linguafelis, rugosa, lacunosa, gar- 

 gadia, pristis, multangula, polygona, capsoides, decussata, 

 Brasiliana, obliqua, umbonellaj deltoidalis, nymphalis, soli- 

 dula, bimaculata, sexradiata, ostracea, flexuosa. 



TELLENIDES. Shell transverse, inequilate- 

 ral, somewhat flattened, gaping a little at the 

 sides ; beaks small, depressed, margin without 

 an irregular fold. Hinge with two diverging 

 teeth on each valve ; lateral teeth two, subob- 

 solete, the posterior approximated to the car- 

 dinal in one valve. 



The tellenides differs from psammobia by having 

 lateral teeth, from tell in a, by wanting the flexuous mar- 

 ginal fold, and from lucina by its gaping, and not hav- 

 ing the internal fascial impressions. 



T. Timorensis rosea. 



CORBIS. Shell transverse, equivalve, with- 

 out an irregular fold at the anterior margin ; 

 beaks curved inwards ; two cardinal teeth ; 

 two lateral, the posterior nearest the hinge ; 

 muscular impressions simple. 



The corbis is principally distinguished from the 

 lucina by the animal inhabiting it, and by not having 

 one of the muscular impressions lengthened into 



