61 



of which are wrinkled by strong spiral striae, alter- 

 nately larger and smaller ; the outer lip of the ovate 

 aperture is toothed internally, and strengthened exter- 

 nally by a strong rib. The canal is short, and slightly 

 oblique, and there are traces of a callosity at the junc- 

 tion of the outer lip with the columella. 



The specimen is 1^^ long, by y^^y broad, and of 

 a yellowish white colour. See the figure. 



IV. Natica. 

 It is strange that the true nature of the animal of 

 the genus Natica should so long have remained in 

 doubt, especially as species of the genus inhabit most 

 seas, and are by no means difficult to procure alive. 

 Adanson's " Natice, No. 1,"' is evidently a Nerita, 

 though the three other species he figures are true 

 Naticae. His remark on the animal of his No. 4, 

 " m'a paru semblable a celui de la premiere espece," 

 (p. 177?) seems to have misled succeeding authors. 

 Deshayes, in his article Natica, (Diet. Class. d'Hist. 

 Nat.) actually describes the " Natice marron," (Na- 

 tica castanea,) as having four tentacula, with the eyes 

 on two penduncles ; and Rang gives similar charac- 

 ters in his Manuel des Mollusques. Lansdowne 

 Guilding, if I recollect right, was the first to describe 

 a Natica fully and correctly, (Lin. Trans, vol. 16.) 

 and more lately, Phillippi has described and figured 

 the animal of the true Natica glaucina, and described 

 that of Natica mille punctata. Guilding conjectured 

 that the Naticae, with calcareous opercula, formed a 



F 



