Echinodermata of St. Andrews. 71 



Fam. 3. Asteriadse. 



Genus 20. Asterias, L. 

 Asterias rubens, L. ; Norman, op. cit. p. 128. 



Abundant between tide-marks and beyond. Many singular 

 varieties, from the loss or partial reproduction of the rays, 

 occur. A specimen shows five large rays, two of which are 

 formed by the splitting of one arm, while in the interspace 

 two small rays situated one over the other occur. They spawn 

 in November ; and many are found in the peculiar stool-like 

 position, grasping the ova, at this season. The same posture, 

 however, is sometimes assumed when devouring Littorina 

 obtusata or other mollusks. 



Asterias violacea, O. F. Midler ; Norman, op. cit. p. 128 



As comn 

 tide-marks. 



As common as the foregoing, and even more so between 



Asterias hispida, Pennant ; Norman, op. cit. p. 128. 



This species has only been seen at St. Andrews by Prof. 

 Edward Forbes, who found several specimens on the sands 

 after a storm in 1839. Although hundreds of small forms 

 have been examined, no specific character has occurred to 

 separate them from the foregoing (A. rubens and A. violacea). 



Order IV. Echinoidea. 



Fam. 1. Cidaridae. 



Genus Echinus, L. 



Echinus esculentus, L. ; Forbes, Brit. Starfishes, p. 149. 



Common amongst the tangles at extreme low water, and in 

 the laminarian region beyond ; young specimens occur under 

 stones between tide-marks. In many the intestinal canal is 

 loaded with fragments of laminarian stalks, pieces of Delesseria, 

 and other seaweeds covered with Membranipora ; in some 

 there are fragments of the shells of Balani and tubes of 

 Serpulw. 



Echinus miliaris, Leske ; Forbes, Brit. Starf. p. 161. 

 Not uncommon under stones in rock-pools. 



