168 TELLTNIDiE. 



Tellina, Linn., 1758. 



Etym. — Telline, the Greek name for a kind of mussel. 



Distr. — Above 300 sp. In all seas, especially the Indian 

 Ocean ; most abundant and highly colored in the tropics. Low- 

 water — coral zone, fifty fathoms. Wellington Channel, Kara 

 Sea, Behring's Straits, Baltic, Black Sea. Fossil, 170 sp. 

 Oolitic — ; United States, South America (Chiloe), Europe. T. 

 rastellam, Hanley (cxi, 56). 



Shell slightly inequi valve, compressed, rounded in front, 

 angular and slightly folded posteriorly, umbones subcentral ; 

 teeth 2-2, laterals 1 — 1, most distinct in the right A'alve ; pallial 

 sinus very wide and deejo ; ligament external, prominent. 



Animal with slender, diverging siphons, twice as long as the 

 shell, their orifices plain ; foot broad, pointed, compressed ; palpi 

 A'ery large, triangular ; gills small, soft and very minutely stri- 

 ated, the outer rudimental and directed dorsally. 



TELLiNELLA, Gray, 1852. Shell oblong, elongated, posteriorly 

 rostrated or subrostrated ; hinge with two lateral teeth in one 

 valve. T. virgata, Linn. 



PERON^ODERMA, Poli, 1795. Shell oval, compressed, posteriorly 

 subangular ; hinge with two lateral teeth in one valve. T. 

 punicea, Born (cxi, 57). Not very distinct from Tellinella. 



MCERA, H. and A. Adams, 1852. (Donacilla, Gray, 1851.) 

 Shell oblong, Donaciform ; posteriorly short, cuneiform, trun- 

 cate ; two lateral teeth in one valve. T. donacina, Linn, 

 (cxi, 58-60). 



PALJEOM(ERA, Stolicz., 1870. Shell elongated, hinder part 

 shorter, the upper declivity slightly convex, posterior end sub- 

 truncate, beaks directed forwards; ligament situated on thickened 

 but not prominent fulcra ; hinge with one anterior, long, laraelli- 

 form tooth in each valve, bifid in the right, single in the left 

 valve, posterior cardinal tooth not distinctl}' traceable in either 

 valve ; laterals less distinct in the left valve. This is based upon 

 the cretaceous Tellina strigata of Goldfuss. In form it very 

 much resembles Moera, but the hinge presents some marked 

 differences, as noted above. 



LTNEARiA, Conrad, 1860. (Liothyris, Conr.) Shell elongated, 

 sometimes roundish, not peculiarly thick, rounded on both ends, 

 surface partially or wholly radiately ribbed, posteriorly not, or 

 very indistinctly flexuous ; anterior cardinal teeth on both valves 

 elongated, bifid, much smaller in the left valve; posterior car- 

 dinal small, but larger in the left than in the right ; lateral teeth 

 much thinner in the left than in the right valve, sometimes almost 

 obsolete in the former. This ought to include a large number 

 of fossil species which have been described as Arcopagise ; the 

 want of posterior flexure or plicature and the usual I'adiate rib- 

 bings near the terminations of the shell particularly characterize 



