TELLINID^. 167 



The genus commenced in the cretaceous period, augmented 

 during the tertiary, and is at its greatest development now. 



PSAMMOCOLA, Blaiuv., 1824. Shell oblong, subquadrangular ; 

 surface smooth. G. maxima, Desh. (cxi, 47). 



AMPHICH^NA, Philippi, 1847. ( Psammobella, Gray, 1851.) 

 Shell oblong, gaping at both extremities ; posterior end rounded. 

 G. modesta, Desh. (cxi, 48). 



HETEaoGLYPTA, Martens, 1880. Posterior portion of the shell 

 difFerentl}^ sculptured. G. squamosa, Lam. 



Sanguinolaria, Lamarck, 1799. 



Etym.-^-From the t3q3e, Solen sanguinolentus, Chemn. 



Syn. — Lobaria, Schum., 1817. 



Distr. — 5 sp. S. rosea, Lam. (cxi, 49\ Fossil; ? Paleozoic--. 



Shell transverse, subelliptical, flattened, equivalve, inequi- 

 lateral, a little gaping at the ends, not angulate posteriorly, 

 covered by a thin, fugacious epidermis ; hinge having two small, 

 unequal, divergent cardinal teeth in each valve, the anterior ot 

 the left valve and posterior of the right valve being the largest ; 

 beaks small; ligament long; margins plain; muscular impres- 

 sions subdorsal, the anterior oval, posterior circular ; paliial 

 impression elongated, with a shallow, narrow sinus. 



HiATULA, Modeer, 1793. 



Syn. — Soletellina, Blainv., 1824. 



Distr. — 40 sp. W. Indies, Red Sea, India, Madagascar, Japan, 

 Australia, Tasmania, Peru. Fossil, 30 sp. Eocene — ; U. S., 

 Europe. H. diphos, Linn, (cxi, 50). 



Valves oval-oblong, compressed, ventral margin usually 

 incurved posteriorly, where the valves are attenuated ; broadly 

 rounded anteriorly; beaks submedian,not prominent; violaceous, 

 under an olive epidermis ; ligament thick, swollen ; one or two 

 very small cardinal teeth in each valve ; muscular impressions 

 rounded, distant ; paliial impression very sinuous. 



PSAMMOT^A, Lam., 1818. Posterior slope a little angulated, 

 but not rostrated. H. violacea. Lam. (cxi, 51). 



PSAMMOTELLA, Blainv., 1826. Shell thin, oval or oblong, pos- 

 terior edge rounded. H. elongata, Lam. (cxi, 52). 



Elizia, Gray, 1852. 



Distr. — 2 sp. East Indies. E. orhiculata, Wood (cxi, 53, 54). 



Shell suborbicular, equivalve, thin, compressed, covered by a 

 shining epidermis ; beaks not prominent, subanterior ; hinge 

 with two oblique cardinal teeth in the right valve, one of which 

 is elongated and bifid, and three teeth in the left valve, the cen- 

 tral one bifid ; paliial impression submarginal. 



