392 BALANID.E. 



dead or alive, would remain for ever imbedded in the tortoise- 

 shell. Dr. R. Ball, of Dublin, informs me, that he has seen 

 specimens in which the shell of the cirripede not only had pe- 

 netrated the carapace, but likewise the underlying bone, and 

 had even entered some way into the body of the turtle : it is 

 well known that the tusk of a boar or the horn of a rumi- 

 nant, when curving in abnormally, will sometimes penetrate 

 deeply into the bones of the face or head ; and this, I be- 

 lieve, is effected, not by the fracture of the bone, but by the 

 absorption of the point pressed on : I conceive a similar 

 process must have taken place in the curious specimens 

 examined by Dr. Ball. 



1. Chelonobia testudinaria. PI. 14, rig. \a — \ (/] 

 fig. 5 ; PI. 15, fig. 1. 



Lepas testudinaria. Linn. Syst. Naturae, 17G7. 



Verruca testudinaria. Ellis. Phil. Transact., vol. 50, 1758, 



PI. 34, fig. 12. 

 Balanus polythalamius. Bock. Naturibrscher, Stuch. 12, 1778, 



fig. 9. 

 Lepas testudinaria. Poll. Testacea Utriusque Sicilian (179 5) 



Tab. 5, fig. 9—11. 

 Coronula testudinaria. Ranzani. Memoire di Storia Naturale, 



Decade 1, (1820). 

 — — De Blainville. Diet, des Sciences Nat., 



(1824), Tab. 117, fig. 2. 

 Chelonobia Savignii (?). Leach. Encyclop Brit. Suppl., vol. 3, 



1824. 

 Astrolepas rotundarius. J.E.Gray. Annals of Philosoph. (new 



series), vol. 10, 1825. 



Shell conical, depressed, heavy : radii rather narrow, de- 

 pressed, generally notched on both sides. 



Hab. — Mediterranean ; west, coast of Africa ; north-cast coast of Australia ; 

 Low Archipelago, Pacific Ocean ; west coast of Mexico, 23° N. Attached to 

 turtles. 



It is impossible to feel sure which of the three species 

 of the genus Linnaeus had in view, when describing his 



