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Natica monilifera, or castanea, Lam. ? — Na- 

 tica glauciKa, Flem. (not of Lamarck.) — 

 Nerita glaucina, Mont, (not of Linnaeus.) 



Shell with six rounded whorls, somewhat flattened 

 at their tops ; the first largest, minutely striated spi- 

 rally under the lens, brownish white ; the upper 

 whorls with obsolete brown markings. Suture deep. 

 Umbilicus large, not furrowed, spirally striated in- 

 ternally. Pillar lip callous, reflected, white, but not 

 covering the umbilicus. Inside brov/nish. Oper- 

 culum corneous. 



Animal undescribed. 



Young shell with the spire much depressed, the up- 

 per part of the whorls with regular brown markings. 



The spirally striated umbilicus distinguishes this 

 species from all the other British naticae. I have 

 doubts as to this being the shell described by La- 

 marck under the name of Natica monilifera. In the 

 British Museum, specimens of this shell are labelled, 

 " Natica castanea, Lamarck.'''' My specimens of 

 what I believe to be that species, from the IMediter- 

 ranean, are certainly not identical with the British 

 shell. Perhaps the giving our species a new name, 

 would be the best mode of removing the confusion. In 

 such case I would propose to name it Natica Nicolii. 



Rare on the Manx shores ; south coast at Port 

 Erin. I have never seen the animal. This species 

 appears to be generally distributed in Britain, and is 

 common in all collections. Mr. Nicol informs me 

 that it is found buried in sand, at very low tides, in 

 the Frith of Forth. 



