HISTORICAL 9 



urchins of a white color', shells, spines, eggs and all, and that are 

 longer than the ordinary sea urchin... 



"All urchins are supplied with eggs, but in some of the species the eggs 

 are exceedingly small and unfit for food, singularly enough, the urchin 

 has what we may call its head and its mouth down below, and a place 

 for the issue of the residuum up above. For the food on which the crea- 

 ture lives lies down below; consequently the mouth has a position well 

 adapted for getting at the food, and the excretion is above near to the 

 back of the shell. The urchin also has five hollow teeth inside, and in 

 the middle of these teeth a fleshy substance serving the office of a 

 tongue. Next to this comes the oesophagus and then the stomach, 

 divided into five parts and filled with excretion, all the five parts 

 uniting at the anal vent, where the shell is perforated for an outlet. 

 Underneath the stomach, in another membrane are the so-called eggs 

 [ovaries] identical in number in all cases, and that number is always 

 an odd number, to wit five... The urchin uses its spines as feet; for it 

 rests its weight on these, and then moving shifts from place to place." 



It is on account of this description that the dental apparatus has 

 been known as "Aristotle's lantern." The passage however, is somewhat 

 confused in the original Greek, some manuscripts reading to CTcofjia 

 (the body), and others to cTTOfxa (the mouth). In the former case, the 

 whole shell is compared to a lantern. D'Arcy Thompson prefers the 

 latter, and gives as a translation, together with the original Greek and 

 a discussion, in his Greek Fishes (1947, p. 71) : "The sea urchin's mouth 

 (or oral apparatus) is from beginning to end a continuous structure; 

 but in surface view it is not continuous, but looks like a lantern with 

 the horn-panes 2 left out all round." His drawing showing the com- 

 parison of the sea urchin's lantern of Aristotle, with an antique lantern 

 is reproduced in Figure 2. Rondelet (1554), Gesner (1558), and Aldro- 

 vandi (1606) speak of Aristotle's comparison with a lantern, but do 

 not call it "Aristotle's lantern." It seems to have been first called 

 "Aristotle's lantern," laternam Aristotelis, by Klein in 1734 (p. 41-42) 

 and Plate 31, Figs, a, b, c). Several standard works on zoology state 

 that Aristotle's lantern was so named by Pliny (e.g., Bronn's Thier- 

 Reich, Bd. II, Abt. 3, Buch IV, p. 1068), but I have found no reference 

 to the lantern in Pliny. 



■ There are several species of white sea urchins, one of which is LyUchinus variegatus, the 

 fornier Toxopneustes variegatus which occurs at Beaufort, N. C. and was used by E. B. Wilson 

 in his classical studies published in the Atlas of Fertilization. The same species in Bermuda is 

 usually brown, occasionally white. In Bermuda, Tripneustes (Hipponoe) esculentus is known as 

 the white urchin. 



2 Horn was used in the place of glass. 



