70 



THE NAUTILUS. 



Studies ON Australian MoLLuscA. Pt. XIII. By C. Med- 

 ley (Proc. Linn. Soc. New South Wales, 1916, vol. 41, pt. 4, 

 pp. 680-719, i)l8. 46-52, issued April 4, 1917). The author's 

 notes under Tridacna gigantea Perry are of such general interest 

 that we quote them in part. " Under the name of Chama gigas 

 the father of Natural History seems to have eml^raced the whole 

 of the modern genus Tridacna. For the name gigas, as restricted 

 to a single species, the candidates are the shell subsequently 

 named -iquamosa by Lamarck and a huge species whose valves 

 in the Ulrica Museum, together weighed 498 pounds. 



"After careful examination, Hanley decided that the fur- 

 belowed clam, such as Reeve has figured for T. squamosa, ought 

 rightly to bear the name gigas. He based his verdict on the 

 ground that the actual shell owned by Linn6 as representing 

 gigas, is the Lamarckian sqiiamosa, and that to this apply most 

 of the literary references. Linnean contemporaries such as 

 Born, Regenfuss and Chemnitz, while making casual references 

 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 the name gigas for the 

 largest form, while for the Linnean gigas he proposed sqiiamosa. 

 Attentive to the remarks of Hanley, Hidalgo in 1903, renamed 

 the biggest species T. lamarcki. But in 1811, Perry had already 

 used the name Chama gigantea for ' the largest shell at present 

 known. ' 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 heaviest known are a pair weighing 550 lbs., which 

 Cuvier 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 free and exposed at low tide, standing on their umbones, 

 and showing their brightly colored mantle and so-called eyes 

 as they gape." 



