IN DESCRIBING SHELLS. 35 



Semi-0)'bicnlata is half a roiiud, as in the genus Neritci. 

 Oblonga is oblong, somewhat of a long oval, as Voluta torna- 



tilis and Murex costatus. 

 Ovah's is nearly a short oval, as Biiccinum Lapillus and Murex 



Erinaceus. 

 Ovata is approaching to an egg-shape, as Helix vicipara and 



palustris. 

 Pynformis is somewhat pear-shaped, as in Murex fuscatus. 

 Cordata is heart-shaped, as in Nautilus Pompilius. 

 Semi-cordalo is shaped like half a heart, as in Trochus Solaris 



and Helix complanata. 

 Quadrata is approaching to square or four-sided, as in many 



of the Trochi, and in Turbo perversus and striatus. 

 Suh-triangndaris is nearly triangular, as in Turbo vertigo and 



sex-dentatus. 

 Semi-lunaris is crescent-shaped, as in Helix rufescens, &c. 

 Utrinque-acuta is when both ends of the aperture terminate 



in a point, as in Helix Plauorbis and Gualteriana. 

 Longitudinalis is lengthwise of the shell, as in the genus Conns, 



and in Cyprcea. 

 Linearis is long and narrow, as in Bulla obtusa. 

 Angustissitua is very narrow, as in Bulla cylindracea. 

 Marginata is with a margin or border round the mouth, as in 



Helix Lapicida and H. Ocidus capri. 

 Reflexa is with the margin bent back, as in Turbo corneus 



and reflexus. 



f2 



