BY c. Medley. 687 



Triiiacna. For the name gi'jas, as restricted to a single species, 

 the candidates are the shell subsequently named squamosa by 

 Lamarck, and a huge species whose valves, in the Ulrica 

 Museum, together weighed 498 lbs. 



After careful examination, Hanley decided that the furbe- 

 lowed clam, such as Reeve has figured (Conch Icon., xiv., 1862, 

 Tridacna, Pi. iii.) for T. squamosa, ought rightly to bear the name 

 oigigas. He based his verdict on the ground that the actual 

 shell owned by Linne as representing gigas, is the Lamarckian 

 squamosa, and that to this apply most of the literary references. 

 Linnean contemporaries, such as Born, Regenfuss, and Chemnitz, 

 while making casual reference to the giant, all agree in figuring 

 and describing squamosa as the Linnean gigas. 



Discriminating in 1819 between the species his predecessors 

 had confused, Lamarck unlawfully used tlie name gigas for the 

 largest form, while for the Linnean giyas he proposed squamosa. 

 Attentive to the remarks of Hanley, Hidalgo, in 190.'^, renamed 

 the biggest species T. lamarcki. \^\xt in 1811, Perry had already 

 used the name Chama gigantea for " The largest shell at present 



known a Bivalve about three feet in length, one foot and 



a half in breadth, the shell itself being four or five inches thick." 



As the young of the giant has not yet been traced to the 

 adult, it is still possible that squamosa is a juvenile deeper-water 

 form of the large intertidal and abraded gigantea. 



The size to which this species ultimately attains is, as Kent 

 and Banfield remark, a favourite subject for romance among 

 travellers. After some inquiries. Smith concluded that the 

 largest authentic record was that by Dillwynof a Sumatran pair 

 which weighed 507 lbs., and of which the largest valve was four 

 feet six inches long, two feet five and a half inches high, and 

 one foot deep. The heaviest known are a pair weighing ooOlbs., 

 which, Cubieres and Lamarck relate, were presented by the 

 Venetian Republic to Francis I. These still exist, their edges 

 bound with brass, as holy-water basins in the cathedral of St. 

 Sulpice, in Paris. 



The photographs of Saville Kent show the giant clams in their 

 natural position on the Great Barrier Reef, where they occur 



