I'L'KPLE EGG-URCHIN. 



167 



ECHIXID.E. 



CIDARITES 



PURPLE EGG-URCHIN. 



Echinus Hindus. Lamarck. 



Specific Character. — Rows of pores bent, five pair in each row above ami 

 centrally, but diminishing in number near the mouth ; spines striated ; ridges 

 broad, smooth ; primary spines longer than secondaries. 



Echinus lividus, Lamarck, 1 Edit. II. p. 50 ; 2 Edit. III. p. 367. Blain- 



ville, Man. d'Actin. p. 228. Bennett, Lin. Trans. 

 vol. XV. 



Echinus sa.ratilis, Linnaeus ? Muller, Zool. Dan. Prod. 2847 ? 



Echinus litluyphagus, Leach, Tillodi-s Phil. Mag. vol. XXXIX. p. 100. 



The Purple Egg-Urchin measures about two inches in 

 diameter when deprived of its spines, sometimes a little 

 more. The spines are usually about an inch in length, 

 very slender and tapering, and of a deep but shining pur- 

 ple hue. There is a variety which has the spines much 

 shorter and thicker, and of an olivaceous green. The 

 spines always present the same character whatever be 

 their form, when magnified being finely striate longitu- 

 dinally, the ridges between the strise rather broad, and 

 both quite smooth. The primary spines are generally 

 somewhat longer than the secondaries, but in the green 

 variety the difference of length is very slight. When the 



