136 Marine Shells of the Western Coast of Florida 



colonies with the coils of the shells intertwined. 



The animal has short tentacles and snout, eyes placed on the 

 outer sides of the tentacles. They are unisexual, and fertilization 

 of the ova is accomplished by water-borne sperm. 



One of the marine snails called Vermetus feeds in a manner 

 peculiar to itself. It has largely lost the power of movement but uses 

 the mucus, which such creatures normally employ to lubricate their 

 movements, to catch its food, throwing out a sheet of sticky mucus 

 in which fine particles and animals are entangled, and after a time 

 drawing this with the collected food back into its mouth.-*-'' Perry 

 has seen V . fargoi in an aquarium feed in this manner. 



Shells of the Vermetidae are free or fixed. The young shells 

 are regularly spiral, easily confused with Turritella, after an inch 

 or less of growth, the whorls become more and more irregular and 

 loosely coiled, gradually increasing their diameter. The aperture is 

 round; a circular, corneous operculum is usually present. 



Distribution is confined to warm and temperate seas. 



Genus PETALOrONCHUS H. C. Lea, 1843 

 Petaloconchus irregularis (d'Orbigny) PI. 26, fig. 182 



This is a reef-building species. Dr. W. H. Dall observed patches 

 20 to 30 feet across, with tops nearly at water level and scarcely 

 dry at low tide. The individual shells are loosely coiled, contorted 

 and inextricably intertwined — only the juvenile tips show any 

 regularity of growth. The external surface usually bears longitudinal 

 ribs which are wrinkled and roughened by circular growth lines. The 

 aperture is round, sharp. Color is reddish chestnut, whitened by 

 calcareous deposits; interior smooth, highly polished. 



Genus YERMICULARIA Lamarck, 1799 

 Yerinicularia-^' kiiorri (Deshayes in Lamarck) PI. 26, fig. 183 



Found living in sponge. Shell is translucent, septate within 

 early whorls. Color brown, purple, pink or white corresponding to 

 color and shade of individual mollusk. Apex is sharp, about five 

 white, acutely carinate, contiguous whorls, followed by loose coils 



243 The Seas, Russell and Yonge. 

 ^** Lat., vermis, worm. 



