30 | The Rev. L. Gurtne on Naticina and Dentalium, 
Umbilicus profundus, sæpè latus, inter columellarium contractum bené separa- 
tum atque columellz basin spiralem et sæpè incrassatam positus : fossuld 
ante callositatem, feré distincta. 
Peritrema acutum, interné levigatum. 
Operculum testaceum, superficie totà affixum, nunc coelato-costatum, nunc pla- 
natum, spiráque ejus antico-internà. 
Typus. Natica caurena, Sow. Gen. f. 1. 
Genus 2. Narticina, Guild. (Natice diminutivum.) Natica, Sow., Lam. 
Character genericus. 
Animal cæcum *, cucullatum. 
Caput absconditum, parvulum, papilliforme. 
Os subtis, cartilagineum, proboscidiforme, intra caput retractile. 
Mandibulæ binæ, æquales, corneæ, marginibus denticulatis. 
Tentacula spuria, longa, debilia, subdepressa, retractilia, apicibus recurvis ; 
basi tecta, et membrana supra caput connexa. 
Cucullus latus, corpus testamque anticè tegens, margineque antico pedi con- 
nexus: dum pascit animal detrahendus. 
Pallium tenue, continuum, latera testæ protegens. 
Operculum corneum, simplex, spira antico-interná, cicatrice parvula. Musculus 
opercularis- lateralis, contractus. Musculus adhesionis ventralis, latus, 
cartilagineus, candidus. 
Pes valdé contractilis et mutabilis, latus, magnus, subdiaphanus, anticé cucul- 
lum recipiens. 
Solea simplex, marginibus tenuibus. 
Anus pallio absconditus, sinister ? 
Branchie subdorsales. 
* In general aspect the Naticine approach the Bulla Hydatis described by Montagu in the Linnean 
Transactions, vol. ix. t. 6. f. 1. p. 106.—This animal, however, like its congeners, has distinct eyes 
seated in the subdiaphanous disk of the hood. 
T The operculum is here only partially affixed to allow of freer motion. In Strombus the elongate lid 
is attached only by one end, the other being used as a crutch: when reversed, it easily recovers its 
position by this singular use of the organ; hence the point is generally worn and uneven. 
