History of British animals - University of Guam Marine Laboratory

A A. Shape various.MOLLUSCA. SIPHONIDA. 409a.Ligament internal.a a.b.Inequivalve. CoRBULADiE.Corbula.bb. Equivalve.MactraDjE.c.Ligament simple.d. Lateral teeth.Mactra.Goodallia.d d.Lepton.Kellia.No lateral teeth.Loripes.Ervillia.c c. A subsidiary external ligament.Amphidesma.Ligament external.b. Two primary teeth, at most, on the same valve. {Nymphacesof Lamark.)c.Ligament at the shortest side, being the posteriorone abbreviated. Donacid^.Donax.Capsa.Tellina.c c Ligament at the longest side.d d.d. No lateral teeth.Psammobia.Astarte.Lateral teeth.Lucina.Myrtea.b b. Three teeth, at least, on the same valve ; the otherwith an equal number, or less. {Conques of Lamark.)c. Marine. Venerid^e.Cyprina.Cytherea.Venus.Venerupis.c.c. Fluviatile. Cyclad.*.Cyclas,Cyrena.(Galateola.)IV. Cloak closed ventrally; the anteal opening small, and notexposing the mouth or and gills, serving as a passage forthe foot ; posterior openings tubular.A. Lodged at the extremity of a calcareous lube with whichit is more or less intimately connected. Tebedinidje.Teredo.Xylophaga.Fistulana.Clavagella.