HELCION. 157 



Lam. — Bescr. Elongated, cylindrical, chambered, recurved at 

 the smaller extremity, annulated ; septa lobed and sinuated. — 

 Obs. This remarkable fossil from the Baculite limestone in 

 Normandy, differs from Baculites in being curved at one extremity, 

 a circumstance from which its name is derived. Some small 

 species are found in Chalk-Marie, Folkstone. Fig. 484*. H. 

 cylindricus. 



HARPA. Brug. (Harpa, a harp.) Fam. Purpurifera, Lam. 

 Entomostomata, Bl. — Bescr, Oval, ventricose, longitudinally 

 and regularly costated ; spire short, with rounded, dome-like 

 whorls ; aperture wide, emarginated ; outer lip thickened, re- 

 flected, composing the last costa or rib ; inner lip polished, spread 

 over part of the body whorl, terminating in a point. — Obs, 

 This beautiful genus of shells is so clearly defined by the regular, 

 longitudinal ribs that adorn the external surface, suggesting the 

 idea of a stringed instrument, that there is no danger of con- 

 founding it with any other. H. multicostata, (Buccinum cos- 

 tatum, Linn.) and H. ventricosa, are among the most elegant of 

 the testaceous productions of the sea both in form and colouring ; 

 the former is rare. The recent species are not numerous, they 

 inhabit the Indian Ocean. A fossil species occurs at Grignon, 

 near Paris. Fig. 419, H. ventricosa. 



HARPAX. Parkinson. Part of Plicatula, Auct. 



HARPULA. Sw. A group of shells separated from Volxjta, 

 Auct. thus described, " shell generally tuberculated or longitu- 

 dinally ribbed ; apex of the spire papillary, smooth, and in general 

 distorted ; pillar with numerous distinct plaits ; the upper, 

 small and slender, the lower, thickest and shortest." — Type, H. 

 Vexillum. (Voluta, Auct.) 



HAUSTATOR. Montf. A genus proposed to include those species 

 of Turritella, Auct. which have angulated whorls. 



HAUSTELLAR1A. Sw. A sub-genus of Murex, consisting of 

 species with long canal and no spines. Murex Haustellum, fig. 396. 



HAUSTRUM. Humph. Purpura, Lamarck. 



HELCION. Montfort. A genus composed of species of Patella, 



