214 NATICID.E. 



assuming a quoit-like form ; it is of a gelatinous 

 consistency, but rendered tolerably firm by the admix- 

 ture of grains of sand. These curious bodies may often 

 be seen lying on the sand at low water of spring-tides 

 in summer. They have been mistaken for zoophytes, 

 and were placed by Solander and Ellis in the genus 

 Flustra, by Pallas in Eschara, and by Lamarck in Dis- 

 copora. il The cells are arranged in quincunx order }> 

 (Gould) . 



The Rev. L. Guilding (Linn. Trans, vol. xvii.) divided 

 this genus into Natica and Naticina, the former having 

 a shelly, and the latter a horny operculum. Gray pro- 

 posed to adopt the genus Neverita of Risso for the 

 species with a horny operculum; but Risso retained 

 Natica for these, and his description and figure of Ne- 

 verita represent a different kind of shell (apparently 

 Natica olla), which has the umbilicus closed by a solid 

 pad. In all our species the operculum is horny. Reeves's 

 list contains 137 recent species of Natica. There are 

 many obsolete generic synonyms. 



A. Shell rather thin, with a produced spire ; umbilicus small. 

 1. Natica Islan'dica*", Gmelin. 



Kerita Islandica, Gmel. ed. S. N. p. 3675. Natica hclicoichs, F. & II. iii 

 p. 339, pi. c. f. 6. 



Body pale yellowish-white, minutely and closely speckled 

 with flake-white : snout broad and large, with rounded cor- 

 ners : tentacles small ; they either project at the sides of the 

 front foot-lobe, or are pressed back by it on the outer lip of 

 the shell : eyes, none observable : fo'jf narrower at the sides, 

 expanded and forming short ear-Shaped lobes in front, thicker 

 and folded back behind into an ar^ular point. 



Shell conic oval, less solid than any other recent British 

 species of Natica, semitrans^ are iit, not glossy when fresh and 



* Icelandic. 



