87 
Sph^enia, Turton. 
Animal ovatum ; pallium antice clausum , prceter aperturam pro 
pede parvo digitiformi sidco byssali instructo; siphones con- 
nati usque ad extremitates , orificia cirrata ; sipho analis val¬ 
vuld tubulari membranaced extra orificium productd. 
Testa oblonga, incequivalva, incequilateralis, magis minusve postice 
Mans ; Icevis, vel rugosa, epidermide tecta ; umbones incurvati ; 
cardo dente laminari dilatato erecto in valvuld sinistra , alveo 
convenienti in valvuld dextra; ligamentum internum; impres- 
siones pallii sinu parvo. 
Animal ovate; mantle closed in front, except an opening for the 
passage of a small digitiform foot furnished with a byssal groove; 
siphons united to their extremities, their orifices cirrated; anal siphon 
with a tubular membranous valve projecting beyond the orifice. 
Shell oblong, inequivalve, inequilateral, more or less gaping poste¬ 
riorly ; surface of the valves smooth or rugose, covered with an epi¬ 
dermis ; beaks incurved ; hinge composed of an erect, dilated, laminar 
tooth in one valve, with a corresponding pit in the other; ligament 
internal; pallial impression with a slight sinuation. 
Sph.enia Binghami, Turton. S. testa incequivalva , incequila- 
terali , ovato-trigonali , transversim concentrice sulcata , epider¬ 
mide olivaceo tecta ; latere antico breviore , rotundato , postico 
longiore , Mante, subtruncato; impressione pallii sinu subpro- 
fundo , rotundato ; dente cardinis valvulce sinistrce postice sub- 
sinuato. 
Hab. in littoribus Britannicis. 
Shell inequivalve, inequilateral, ovately trigonal, transversely con¬ 
centrically sulcated, covered with an olivaceous epidermis ; anterior 
side shortest, rounded, posterior side longest, gaping, subtruncate; 
sinus of pallial impression rather deep and rounded; tooth of left valve 
posteriorly sinuated. 
Hab. British islands. 
Sph^nia decussata, Deshayes, sp. S. testa ovato-oblongd , sub- 
cequilaterali i postice truncatd, subrostratd, rostro basique ob¬ 
lique carinatd , alba , striis longitudinalibus , transversisque 
tenuissime decussata ; umbonibus magnis, oppositis ; dente car- 
dinali magno , obliquo, compresso in valva sinistra , in valvdi 
dextra foveola profunda , marginatd. 
Hab. in Sumatrse maribus. 
Shell ovately-oblong, subequilateral, posteriorly truncated, sub- 
rostrate, beak and base obliquely carinated, white, very finely decus¬ 
sated with longitudinal and transverse striae; umbones large, oppo¬ 
site ; cardinal tooth large, oblique, compressed in the left valve, in 
the right valve a deep marginated pit. 
Hab. Seas of Sumatra. 
Sph^enia semistriata, Hanley, sp. S. testa albdi, transversd 
ovali, inequilaterali , concentrice striata; latere antico breviore , 
