10 



THE AMERICAN ARBACIA 



Fig. 2. (A.) The lantern of Aristotle. (B.) A Greek lantern, from D'Arcy Thomp- 

 son, A Glossary of Greek Fishes (Oxford University Press, London, 1947). 



In his De Partibus Animalium (translation by Wm. Ogle, 191 1 , p. 680^) 

 Aristotle repeats much of this description of the sea urchin, noting 

 especially its spherical shape and the radial symmetry of its organs and 

 its edible eggs, and adds: "Though the ova are to be found in these 

 animals even directly they are born, yet they acquire a greater size 

 than usual at the time of the full moon; not as some think, because sea 

 urchins eat more at that season, but because the nights are then 

 warmer, owing to the moonlight. For these creatures are bloodless, 

 and so are unable to stand cold and require warmth." 



In his De Generatione Animalium (v. 3, translation by A. Piatt, 19 10, 

 p. 783*) Aristotle's speculations are interesting but completely un- 

 scientific. The sea urchins "have large and hard spines because the 

 sea in which they live is cold on account of its depth (for they are 

 found in sixty fathoms and even more). The spines are large because 

 the growth of the body is diverted to them, since having little heat in 

 them, they do not concoct their nutriment and so have much residual 

 matter and it is from this that spines, hairs and such things are formed ; 

 they are hard and petrified through the congealing effect of the cold." 



Pliny (23-79 A.D.) has repeated in his Natural History (ix. 51, trans- 

 lation by Bostock and Riley, 1890-1900, vol. 2, p. 427) some of the 

 description of Aristotle. Pliny says that the sea urchin has spines in- 

 stead of feet, has a mouth in the middle of the body on the under side, 

 and has five ovaries, and notes that the eggs are bitter. He also, like 



