NATICA. 325 



NATICA, Bruuiere. 



Shell more or less globular, usually strong, with a short 

 spire of few volutions ; surface usually smooth or very 

 finely striated ; often polished ; aperture ovato-pyriform, 

 outer lip acutely edged ; inner lip more or less expanded 

 or callous, encroaching on and sometimes concealing the 

 umbilicus. Operculum corneous or calcareous, elliptical, 

 with a small spire. 



Animal very large in proportion to the shell, but always 

 perfectly retractile. Head small, furnished with a long 

 trunk, and surrounded by a tentacular veil, from which two 

 lanceolate tentacles, set well apart, spring ; eyes usually 

 absent, when present very minute, and placed beneath the 

 tentacular veil ; foot very large and expanded, rounded at 

 both ends ; mentum greatly developed, forming a large ob- 

 long disk in front of the shell, the anterior portion covering 

 the foot, the posterior reflexed upon the head and tentacula, 

 so that the tips only of the latter appear above it when the 

 animal is walking. Operculigerous lobe very ample, reflexed 

 upon and partially concealing the shell both at the sides and 

 back : jaws distinct, corneous ; tongue short, linear, each 

 row of teeth upon it consisting of a quadrate, broad based 

 median tooth with a denticulated apex, flanked by three 

 uncini on each side ; male organ falcate ; branchial plume 

 single. 



The spawn of Natica is deposited in the form of a sub- 

 spiral or concentric ribband or strap, rendered firm by 

 agglutinated sand. 



The species of this genus inhabit every climate, but are 

 most numerous in warm regions. Some of them, as the 

 Natica hercules from Oregon, grow to a large size. 



