= 
On 
_ 
CLASS XII. 
to Pout. The species are numerous, and the fossil, of which some corre- 
spond to forms still living, belong principally, though not exclusively, to . 
the tertiary formations. 
Sp. Solen vagina L., Potr Test. utr. Sic. 1. Tab. xX. figs. 5, 6, Buarnv. 
Malacol. P|. 79, fig. 2; in this species the hinge lies almost entirely at the 
anterior end of the shell, and has only one tooth on each valve. In other 
species it is situated further backward, always however nearer to the 
anterior than to the posterior extremity of the shell; ex. gr. Solen legumen 
L. from the Medit., Solen radiatus L., Rumpx. Amb. Rariteitk. Tab. 45, 
fig. H, from the Indian Ocean, &c. 
Solemya LAM. (more correctly Solenomya MENKE, PHILippt). 
Shell inequilateral, shorter posteriorly, rotundate at both extremi- 
ties, covered with a periostracon, produced beyond the margins of 
shell. Hinge callous, edentulous. Animal with trachea short, 
branchia on each side single, plumose, formed of lanceolate lamellee, 
disjoined, disposed in two series. Foot large, cylindrical, termi- 
nated by a disciform expansion, fimbriated at the margin. 
Sp. Solenomya mediterranea, Tellina togata Pout, 1. Tab. 15, fig. 20, DmsH. 
Conchyl. Pl. 3, figs. 15—17. The animal is figured by DELLE CHIAJE 
Memorie sulla storia e Notom. degli Anim. s, v. Tab. 62, figs. 10, 11, PHI- 
LIPPI in WIEGMANN Archiv fiir Naturgesch. 1835, Taf. Iv. s. 171—276, 
and DESHAYES in Cuv. R. Ani., éd. ill., Moll. Pl. 115. Comp. also 
DesHayeEs Encycl. méth., Vers. 11. pp. 956, 957.—Solen australis LaM., 
Buainv. Malac. Pl. 79, fig. 1. 
Family XXII. Pholadacea. Mantle sacciform, open ante- 
riorly, with a fissure emitting the truncated foot. ‘Two fistulous 
tracheze, very long, conjoined in most, contained in a common 
covering. Branchie elongate, free at the apex, produced within 
the trachee. Shell at each end gaping, with no ligament, a 
styliform or spoon-shaped process at the hinge in each valve 
advancing into the cavity of shell. 
Pholas L. Shell inequilateral, elongate posteriorly, thin, equi- 
valve. External accessory calcareous parts at the hinge. Animal 
(Hypogea Pout) with foot short, thick, its disciform apex flat or 
excavated. Two long trachez conjoined. 
Stone-borers (pwrds from gdwréw, to lie hid in a hole); some of these 
animals live at the bottom of the sea near the strand; others penetrate 
very hard rocks, madrepores, corals, &c.—From the opening at the hinder 
end of the shell turned upwards proceed the two connected tubes into 
which the mantle is prolonged. The mantle is thrown over the hinge, and 
contains small supernumerary pieces of shell of various form in the different 
