BIVALVE MOLLUSCA. 405 
species of these bivalves for representation.  Sfondylus regius 
(Fig. I., Plate XIX.) is, perhaps, the most remarkable for its immense 
spines. Spondylus radians, Lamarck (Fig. III.), is noted for its 
elegant form. Spondylus avicularis (Fig. IV.) shows remarkable 
inequality in the valves. Spondylus imperialis, Chenu (Fig. II.), has 
long projecting spines, like feet ; and the Scaly Spondylus (S. crassis- 
lags Fig. V.) is covered with scales arranged like so many roofing- 
tiles. 
Like Ostrea, the genus Sfondylus is frequently found firmly rooted 
Fig. 177.—Pecten plica (Linnzeus). Fig. 178.—Pecten japonica (Gmellin). 
to rocks and other submarine bodies, and, oftener still, heaped one 
upon the other, like herrings in their barrel. 
These animals belong essentially to the seas of warm countries. 
We find them, however, occupying considerable space in the 
Mediterranean, where the S. gederopus (Fig. VI.) abounds. 
_ But the most remarkable species of all is assuredly Spondylus 
regius (Fig. I., PLate XIX.) This species is a native of the Indian 
Ocean, and at one time there scarcely existed three fragments of 
this rare shell in the museums of Europe. M. Chenu relates in one 
of his books an anecdote which would prove—if any proof were 
necessary—how far the desire of a collector to obtain possession of 
some rare and costly specimen will carry him in order to attain his 
object. “M. R——,” says M. Chenu, “was Professor of Botany to 
the Faculty of Paris, and was, as sometimes happens, more learned 
than rich; he wished, on the invitation of a stranger, to purchase 
one of these shells at a very high price, which might be from 3,000 
