THE MOLLU8CA HEDLEY. 505 



axe heads.* The natives of the Solomon Islands prefer fossil to 

 recent shells for this purpose, f 



What information we have, suggests that the range of this 

 species is almost co-extensive with that of the reef-building 

 corals. 



Weights and measures of sundry large individuals have lately 

 been published by Smith,! his maximum record being five hundred 

 and seven pounds weight, and fifty-four inches in length. This is 

 almost reached by an unquoted record from the Isle of Pines, New 

 Caledonia. Dr. T. Mialaret writes: " In the middle of the 

 peninsula which encloses the Bay of Oupi on the east, there occurs, 

 sunk in the coral, the edges of its valves level with the surface of 

 the rock, a gigantic Tridacna measuring at least 1 metre 20 in 

 length. At the request of Admiral Courbet, we attempted in 

 1882 to extract it, but all our efforts were in vain." 



The genus Tridacna appears to suffer from a superfluity of 

 specific names. No characters of permanent value separate T. 

 squamosa from T. gigas. These forms are usually if not invariably 

 free.jj On the contrary, the habit of T. elongata is to bury itself 

 in rock, a habit always causing variability in shape. 



Hanley states that it was upon what Lamarck called " T. 

 squamosa " that Linne himself founded his Chama gigas.*\ 



TRIDACNA ELONGATA, Lamarck. 



Reeve, loc. cit., pi. ii. ; Valliant, Ann. Sci. Nat., iv., 1865, pp. 

 65- 172, pis. viii. - xii. 



This species is abundant, perforating dead coral in the Funafuti 

 lagoon. So firmly does the foot adhere, that when wrenching the 

 shell out of its burrow, I have sometimes torn the animal asunder, 

 leaving the foot attached to the rock. The position of the shells 

 embedded in dead coral is well displayed in one of W. S. Kent's 

 photographs.** 



The natives, who distinguish it from the preceding as " Fasua 

 noa," also use it as food. 



The range of T. elongata appears to exceed that of T. gigas, 

 the furthest southern point reached by it in the Pacific being 

 Lord Howe Island. 



* Valliant- Bull. Soc. Geol. Fr., xxv., 1868, pp. 681 -G87. 

 t Willey Nature, Oct. 1896, p. 523. 

 J Smith Proc. Malac. Soc., iii., 1898, p. 112. 



Mialaret L'lle des Pins, son Passe, son Present, son A.venir, 1897, 

 p. 63. 



Kent Great Barrier Eeef, 1893, pp. 44-45, pi. xxix. 

 T Hanley Ipsa Linnaei Conchylia, 1855, p. 85. 

 ** Kent Loc. cit., foreground of No. 1, pi. iv. 

 Ii 



