distinct genus from those with corneous opercula, 

 distinguishing the latter (to which section belonged 

 the animal he described,) by the name of Naticina. 

 But such distinction does not appear to be generic 

 as regards the animal. Of Natica mille punctata, 

 which has a calcareous operculum, Phillippi observes, 

 " Animal eandem structuram offert a Natica glau- 

 cina," which latter has a corneous operculum. The 

 animal of two species of calcareous-operculated Naticae, 

 which I had the good fortune to obtain during a visit 

 to Algiers in May last, exactly agreed in generic 

 character with the British corneous-operculated spe- 

 cies I had examined at home, excepting that one of 

 the two presented a most remarkable anomaly, — the 

 presence of eyes. These eyes are sessile, and situ- 

 ated at the junction of the tentacular veil with the 

 body, almost directly under the respective tentacula. 

 No such organs existed in the other species I exa- 

 mined, and I have searched for them in vain in the 

 British species. It seems to me that the eye is a 

 specific, and not a generic organ in the family. 

 Colour is decidedly specific among the Naticidae. 



Besides the British species of Naticae previously 

 noticed, there is another by no means rare on many 

 parts of the coast, which is supposed by many to be a 

 variety of Natica nitida of Donovan, and is probably 

 that author's Natica intricata. Mr. Alder refers it 

 to the Natica Yalenciensii of Payraudeau. The spe- 

 cimens in my collection, which I owe to the kindness 

 of my friend Dr. Knapp, who obtained them at St. 



