Chap. 51.] TATtlOUS KINDS OF CRABS. 427 



while the sun is passing through the sign of Cancer, the dead 

 bodies of the crabs, which are lying thrown up on the shore, 

 are transformed into serpents. 



To the same class 82 also belongs the sea-urchin, 83 which has 

 spines in place of feet i 84 its mode of moving along is to roll 

 like a ball, hence it is that these animals are often found with 

 their prickles rubbed off. Those among them which have the 

 longest spines of all, are known by the name of echinometrae, 86 

 while at the same time their body is the very smallest. They 

 are not all of them of the same glassy colour ; in the vicinity 

 of Torone 86 they are white, 87 with very short spines. The eggs 83 

 of all of them are bitter, and are five in number ; the mouth 

 is situate in the middle of the body, and faces the earth. 89 It is 

 said 90 that these creatures foreknow the approach of a storm at 

 sea, and that they take up little stones with which they cover 91 

 themselves, and so provide a sort of ballast against their volu- 

 bility, for they are very unwilling by rolling along to wear 

 away their prickles. As soon as seafaring persons observe 

 this, the}' at once moor their ship with several anchors. 



(32.) To the same genus 92 also belong both land and water 93 

 snails, which thrust the body forth from their abode, and 

 extend or contract two horns, as it were. They are without 



82 Of animals covered with a thin crust. 



83 The sea-urchin, the herisson de mer of the French, and the Echinus 

 of Linnaeus. 



84 Cuvier remarks, that it does not use the spines or prickles for this 

 purpose, but that it moves by means of tentacules, which it projects from 

 between its prickles. 



85 The Echinus cidaris of Linna3us ; with a small body, and very long 

 spines. The name, according to Hardouin, is from the Greek, meaning 

 the " mother of the echini." 



86 See B. iv. c. 17. 



67 The same, Cuvier says, with the Echinus spatagus of Linna3us. 



88 Not "ova," Cuvier says, but " ovaria" rather. Each urchin has five 

 " ovaria," arranged in the form of stars. They are supposed to be herma- 

 pbroditical, but there is considerable doubt on the subject. 



89 The mouth of the sea-urchin, armed with five teeth, is generally turned 

 to the ground, Cuvier says. 



90 Plutarch, in his Book "on the Instincts of Animals." Oppian, Halieut. 

 B. ii. 1. 226, and JElian, Hist. Anim. B. vii. c. 44, all mention this. 



91 This idea probably arose from the fact of their being sometimes found 

 with stones sticking between their spines or prickles. 



92 The thin-crusted animals. 



93 Known to us as periwinkles. 



