IN DESCRIBING SHELLS. 35 



Semi-orbmilata is half a round, as in the genus Nerita. 

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



tilis and Murex costatus. 

 Ovalis is nearly a short oval, as Buccinum Lapillus and Murex 



Erinaceus. 

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



palusti^is. 

 Pyrifmnnis is somevt^hat pear-shaped, as in Murex fuscatus. 

 Cordata is heart-shaped, as in Nautilus Pomjnlius. 

 Semi-cordata 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. 

 Sub-triang^ularis is nearly triangular, as in Turbo vertigo and 



sex-dentatus. 

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

 Utrinque-acuta is w^hen both ends of the aperture terminate 



in a point, as in Helix Plaiwrbis and Gualteriana. 

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



and in Cyprcea. 

 Linearis is long and narrow, as in Bulla obtusa. 

 Angustissima is very narrow, as in Bidla cylindracea. 

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



Helix Lapicida and H. Oculus capri. 

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



and refiexus. 



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