58 LEPAS. 



There is something very singular in the locality of 

 particular shells. The JL. testudinaria is found only on 

 the turtle ; it is not known on the whale, though it is by 

 no means confined to particular seas. It is said to be 

 common on the backs of turtles in the Mediterranean. 

 Petiver mentions it on those of the Isle of Ascension, 

 and Rumphius on the turtles of the southern coasts of 

 Amboina. The L. diadema, on the contrary, confines 

 itself to the whale ; it is never seen in any other situa- 

 tion, though it might with equal ease take up its abode 

 elsewhere. Again, the L. testudinaria is careful to fix 

 itself on the most convex part of the turtle-shell, where 

 it can remain in security, beyond the reach of the ani- 

 mal's fins. These habits, which are independent of all 

 instruction, can be referred only to that instinct which 

 pervades every part of animated nature, and which 

 seems to be impressed upon the constitution of even the 

 most insignificant being. 



BELL ACORN. 

 PI. 6./. 1, 2. Mr. Sowerby. 



§. Lepas tintinuabulum. L. testa conica obtusa rvgosa. Linn. Syst* 



Nat. ed. 12. p. 1108. Linn. Gmel. p. 3208. 

 Shell conic, obtuse, and rugged. 

 Balanw, testa purpurascenti gibba, longitudinaliter striata, operculo 



postice rostrato, radiis transverse striatis. Brug. Encycl. Meth. Hist. 



Nat. torn. 6. p. J 65. 

 Lepas tulipa, testa subcubica leevi, operculis acutis transversim striatis. 



Mull. Zool. Dan. p. 251. 

 Lister, Conch, t. 443. f. 385. Ellis, Phil. Trans, vol. 50. t. 34. f. 8, 9. 



D'Argenv. Conch, t. 26. f. A. B. Favanne, t. 59. A. Hutch. Dorset. 



p. 25. t. 1. f. 5. Chem. Conch. 8. t. 97. f. 828—831. Donov. Br. 



Shells, t. 143. Mont. Test. Brit. p. 10. Linn. Trans. 8. p. 25. 

 /3. Tulipa alba. Chem. Conch. 8. t. 98. f. 832. 



This shell is composed of six unequal valves con- 



