PARTS OF ANIMALS, IV. v. 



their position and size. For the details of these, con- 

 sult the Researches upon Animals^ and the Dissections. 

 Some points are better explained by inspection'' than 

 in words. 



The Sea-urchin and the genus of Ascidians are 

 peculiar among the Testacea. The Sea-urchin has 

 five teeth,^ and between them it has the fleshy sub- 

 stance (the same as in all the above-mentioned 

 creatures) ; after that, the gullet, after that, the 

 stomach, which is divided into several compartments, 

 so that the animal seems to have several stomachs. 

 But although they are separated from each other and 

 are full of residue, they all spring from the gullet and 

 they all terminate in the residual vent. Apart from 

 the stomach, these creatures contain no fleshy sub- 

 stance, as I have said. They have, however, what 

 are called ova ^ ; there are several of them and each 

 is in a separate membrane ; and scattered at random 

 round the body, beginning from the mouth, are 

 certain black objects,^ which have no name. There 

 are several kinds of Sea-urchin, and in all of them 

 these parts are present. Not all, however, have 

 edible^ ova, and, except in the common^ varieties, 

 they are quite small. There is a similar distinction 

 among the other Testacea : the flesh is not equally 

 edible in all of them, and in some of them the residue 

 (the so-called mecon) is edible, in others not. In the 

 spiral shells, the mecon is in the spiral, in univalves 



** These are really ovaries (or testes) : gonads. 



* These may be the ambulacral vesicles, but the identifica- 

 tion is not certain. 



' See the story of the Spartan in Athenaeus iii. 41. 



' The word translated " common " may mean " living near 

 the surface." 



' S27 



