15 



peculiarity of the shell is a broad notch in the columella, which has all the 

 appearance of being broken. 



Mr. Cuming collected several of the only species known {Nerita radula, 

 Linnaeus) at the Philippine Islands, but never met with any but dead 

 specimens. 



Figure. 



Neritopsis kadula. PI. 16. Pig. 85. Shell, showing its granuled sculp- 

 ture and peculiar notch in the columella. 



Genus 4. NARICA, Becluz. 



Animal ; head with the tentacles subulate, having eyes sessile on 

 their outer bases ; foot small, circular, with a dilated iving-like 

 expansion on each side, produced in front into a lobe. 



Shell ; subglobose, slightly umbilicated, white ; spire short ; last 

 whorl rather inflated ; aperture rounded ; lip simple, with the 

 margins nearly entire. 



The original type of this genus is a shell figured by Chemnitz with the 

 name Nerita cancellata. Lamarck, observing it to be of light, latticed, 

 chalk-white substance, slightly umbilicated, included it in Sigaretus. MM. 

 Quoy and Gaimard met with living specimens during the voyage of the 

 ' Astrolabe/ and referred it to Velutina. They, however, expressed their 

 opinion that it might be set apart for the formation of a new genus, and 

 suggested Yanihoro, the name of one of the islands of the Pacific. The 

 rules of our nomenclature will not allow of the use of this term, — as well 

 might a genus be named Great Britain or Ireland, — and I therefore adopt 

 the name of Narica, subsequently proposed for it by M. Recluz. In the 

 'Revue de la Societe Cuvierienne ' for 1844, that naturalist, who has paid 

 particular attention to the families of the Nerita, Sigareti, and their allies, 

 published a monograph of the Narica, and we have now a very natural 

 assemblage of twenty-six species. 



Species. 



1. acuta, Recluz. 4. cidaris, Recluz. 7. Cuvieriana, Recluz. 



2. Blainvilleana, id. 5. clathrata, id. 8. Deshayesiana, id. 



3. cancellata, Chemn. 6. Cumingiana, id. 9. distans, id. 



