746 CLASS XII. 
Sp. Petricola roccellaria Lam., DesH. Conchyliol. Pl. 12, fig. 7, &e. (on the 
animal of Petricola see Puiuipri 1. 1. p. 188, Tab. vil. figs. 11—14)- 
Fossil species from the tertiary formations are known, 
Savicava FLEURIAU DE BELLEVUE, Lam. (Hiatella Daup., 
Lam., Byssomya Cuy.). Shell with tooth obsolete, tuberculiform, 
or edentulous. Foot very large, often byssiferous. 
Sp. Sawicava pholadis Lam., Mytilus pholadis L., MuntiEr Zool, Danie. 
Tab. 87, figs. 1—3 (infer.), Buainv. Malacol. Pl. 80, fig. 5; Sawicava 
arctica PHILIPPI, Solen minutus L., Lam., Mya arctica L., Hiatella arctica 
Lam., Encycl. méth., Vers. Pl. 234, fig. 4, Buainv. Malac. Pl. 80, fig. 6 
(named Rhomboidis rugos.), Cuv. R. Ani., Moll. Pl. 110, fig. 1, &e. 
Family XVII. Tellinacea. Mantle with lobes concrete poste- 
riorly, margin tentaculiferous. Trachez two, separate, often very 
long. Foot triangular, compressed. Shell transverse, equivalve, 
inequilateral, with posterior part often shorter. Ligament external. 
Two muscular impressions remote. Impression of mantle sinuate 
posteriorly. 
That margin of the shell which is ordinarily the longest, is here often the 
shortest, the hindmost, namely, or that where the ligament is situated. It 
was an error, therefore, in LAMARCK to suppose that in Donaz the liga- 
ment is displaced, and lies on the dwnula; it lies, as in all bivalve shells, 
behind the point. 
Donax L. Shell transverse, posteriorly obtuse, flat. Cardi- 
nal teeth ‘two either in both valves or in left, a single tooth bipar- 
tite in right; lateral tooth single or two lateral teeth, subremote, 
sometimes obsolete. Ligament short. Animal (Peronea Po.) 
with trachez long, distinct, unequal, the inferior longer ; cirri at the 
orifice of anal (superior) trachea simple, at the orifice of branchial 
trachea ramoso-digitate. Foot large, conspicuous. 
Sp. Donax scortum L., D’ARGENVILLE Conchyl. Pl. 21, fig. L, BLArnv. 
Malac. Pl. 71, fig. 1, DESHAYES Conchyl. Pl. 14, figs. 12—15 (Donaa 
pubescens Li. variety); hab. Indian Ocean ;—Donax trunculus L., Pout 
Testac. ulriusg. Sicil. 11. Tab. 19, figs. 12—20, Buainv. Malac. Pl. 71, 
fig 25. GuCs 
(Capsa Lam. Lateral teeth none.) Sp. Donaw brasiliensis Buatnv., 
Capsa brasiliensis Lam., Encycl. méth., Vers. Pl. 261, fig. 10, BLAINv. 
Malac. Pl. 71, fig. 3. 
Psammobia LAM. (and Sanguinolaria ejusd.). Shell transverse, 
subequilateral, subhiant at both ends. Hinge with two teeth, 
more rarely with single tooth in each valve, lateral teeth none. 
