54 LITTORINID.E. 



native of the Gulf of California, An allied species 

 (Turbo minutus, Totten) appears to be its representative 

 on the east coast of North America ; this has a smaller 

 and more oval shell, with convex whorls. 



" In summer it is the chief food of the grey mullet ; 

 in winter various sea-birds feed upon it " (Hyndman) . 

 Its own subsistence is derived from Enter omorpha, Con- 

 ferva, and other delicate seaweeds; and I can testify 

 that it can fast a long while, having kept live specimens 

 for many days in a vessel which contained nothing but 

 water, without observing any diminution of their viva- 

 city. Males are very much smaller than females (from 

 which my description has been taken), and their shells 

 have no keel. The former sex is probably the Turbo 

 subumbilicatus of Montagu. The hollow space between 

 the two edges in front of the foot is lined with vibratile 

 cilia, by the action of which a fluctuating motion is pro- 

 duced when the animal is crawling, and a tremulous one 

 when it is at rest. The faeces are elliptic. Occasionally 

 the surface of the shell is eroded and pitted, so as to ex- 

 pose the innermost layers ; or the top whorls are trun- 

 cated. In the latter case a rude semispiral partition is 

 formed by the upper fold of the mantle, as in Truncatella 

 truncatula. T^he spire is now and then seen to be un- 

 naturally lengthened, evidently owing to some accident 

 in early growth, when a fresh start had to be made. The 

 shell is extremely variable in size and comparative con- 

 vexity. My largest specimen (from Southampton) is 

 upwards of four lines long. 



It is the Bulimus anatinus of Poiret, and Turbo muri- 

 aticus of Beudant, generically changed by Draparnaud 

 and Lamarck to Cyclostoma and Paludina. Orsted de- 

 scribed it as Paludinella vulgaris. I regard also the 

 Paludina balthica of Nilsson and P. minuta of Eequien 



