GASTEROPODA PECTINIBRANCHIATA. 357 





 with it, as fast as it increases in size, various foreign bodies, 

 such as little pebbles, fragments of other shells, 8cc.; it fre- 

 auently covers its umbilicus with a testaceous plate(l). 

 The margin of others, however, is rounded, such as 



Tr. cinerarius, L.j Chemn., V, clxxi, 1686. A small species, 

 and the most common on the coast of France; greenish, obliquely 

 streaked with violet. 

 Some umbilicated Trochi have a prominence near the bottom of 

 the columella(2), 



And, finally, there are others in which it is longitudinally cre- 



nate(3). The 



Solarium, Lam. 



Is distinguished from all other Trochi by a very broad conical spire, 

 at the base of which is an extremely wide umbilicus in which may 

 be seen the internal edges of all the whorls, marked by a crenated 

 cord(4). 



EvoMPHALus, Sowerby. 



Fossil shells resembling a Solarium, but wanting the dentations on 

 the internal whorls of the umbilicus(5). The genus 



Turbo, Lin. (6) 



Comprehends all the species with a completely and regularly turbi- 

 nated shell, and a perfectly round aperture. Close observation has 

 caused them to be greatly subdivided. In the 



Turbo, Lam. 



The shell is round or oval, and thick; the aperture completed on 

 the side next to the spire, by the penultimate whorl. The animal 



(1) Add; Trochus indicus, Chemn., V, clxxli, 1697 98; Tr. imperialis, 

 clxxiii, 1714, and clxxiv, 1715; Tr. solans, lb., 1701 1702, and 17161717; 

 Tr. planus, lb., 1721, 1722. 



(2) Tr. virgatus, Chemn., V, clx, 1514 15; Tr. niloticus, Chemn., V, clxvii, 

 16057, clxviii, 1614; Tr. vermis. Id., clxix, 1625 26; Tr. inasqualis, 

 clxx, 1636 37; Tr. magnus, clxxi, 1656 57; Tr. conspersus, Gualt., Ixx, 

 B.; Tr. jujuUniis, clxvii, 1612 13. 



(3) Tr. maculaius, clxviii, 1615 1616; Tr. cosfatus, clxix, 1634; Tr. viri- 

 dis,c[xx, 16U;Tr.radlatus, lb., 164042. 



(4) Tr. perspectivus, L. Chemn., V, clxxii, 1691 96; Tr. stramineiis, lb., 

 1699; Tr. variegatus, lb., 1708 1709; Tr. infundibuliformis, lb., 17061707. 



(5) Evomphalus pentangulatus, Sowerb., Min. Conch., I, pi. xlv, f. 2;Ev. no- 

 dosiis. Id., xlvl, &c. 



(6) This great genus constitutes the family Cricostoma of Blainvillc. 



