NOTES AND QUERIES. 



119 



(covered with large barnacles), which was stranded on one of the 

 beaches of the estuary of the River Camel, about a mile and a half 

 from the sea. This Crab was identified at the Marine Biological 

 Association of the United Kingdom at Plymouth, and will be placed 

 in the Association's collection at that place. — A. St. George 

 Sargeaunt (Exbury, Padstow). 



OPHIUEOIDEA. 



Rate of Regeneration in a Brittlestar. — The Common Brittle- 

 star (Ophiothrix fragilis) shown in the accompanying illustration 

 was placed in an aquarium at the Horniman Museum on the night of 

 October 19th, 1914. The Brittlestar had broken off the distal ends 

 of each of its five arms shortly after capture on that day, but the 

 animal was healthy, and the lost ends have been in great part re- 



generated. At the time of taking the photograph (1.30 p.m. on 

 February 19th, 1915, i. e. one hundred and twenty-two clear days 

 after fracture) the regenerated portions were respectively 6, 5, 4, 7, 

 and 6 - 5 mm. in length. The average length of the regenerated parts 

 of the five arms on February 19th was therefore 5-7 mm. If 5-7 mm. 

 in one hundred and twenty-two days could be assumed to be the 

 average rate of regeneration in the arms of other individuals of 

 Ophiothrix fragilis, then we may conclude the average rate in a year 

 to be about 17 mm. There are six other Common Brittlestars in the 

 aquarium, all of which are regenerating lost parts of their arms, but 

 I am not quite sure of the dates on which the arms were broken, 

 and I cannot therefore calculate the rate of regeneration. — H. N. 

 Milligan. 



