30 The Rev. L. Guilding on Naticina a7id Dentalium, 



Umbilicus profundus, Sfepe latus, inter columellaiium contractum ben^ separa- 

 tum atque columella? basin spiralem et ssepfe incrassatam positus : fossuld 

 ante callositateni, fer^ distinctii. 



Peritrema acutum, intern^ Isevigatum. 



Operculum testaceum, superficie tota affixum, nunc coelato-costatum, nunc pla- 

 natum, spiraque ejus antico-interna. 



Typus. Natica caurena, Sow. Gen. f. 1. 



Genus 2. Naticina, Guild. (Naticse diminutivum.) Natica, Sow., Lam. 



Character genericus. 

 Animal caecum *, cucullatum. 

 Caput absconditum, parvulum, papilliforme. 

 Os subtils, cartilagineum, proboscidiforme, intra caput retractile. 

 Mandihulw binse, eequales, corneas, marginibus denticulatis. 

 Tenfacula spuria, longa, debilia, subdepressa, retractilia, apicibus recurvis ; 



basi tecta, et meinbrana supra caput connexa. 

 Cucullus latus, corpus testamque anticfe tegens, margineque antico pedi cou-- 



nexus : dum pascit animal detrahendus. 

 Pallium tenue, continuum, latera testa; protegens. 

 Operculum corneum, simplex, spira antico-interna, cicatrice parvula. Mu.sculus 



opercularisf lateralis, contractus. Mu.sculus adhwsionis ventralis, latus, 



cartilagineus, candidus. 

 Pes valdfe contractilis et mutabilis, latus, magnus, subdiaphanus, antic^ cucul- 



lum recipiens. 

 Solea simplex, marginibus tenuibus. 

 Anus pallio absconditus, sinister ? 

 Branchice subdorsales. 



* In general aspect tlie Naticina: approach the Bulla Hydatis described by Montagu in the Linnean 

 Transactions, vol. ix. t. 6. f. 1. p. 106.— This animal, however, Uke 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 itis 

 position by this singular use of the organ ; hence the point is generally worn and uneven. 



