THE ZOOLOGIST 



No. 897.— March 15th, 1916. 



OBSEEVATIONS ON THE FEEDING HABITS OF THE 

 PUKPLE-TIPPED SEA-UBCHIN. 



By H. N. Milligan. 



Although the Purple-tipped Sea-Urchin {Echinus miliaris) 

 is very abundant around our shores, and is doubtless often kept 

 in aquaria, our knowledge of its feeding habits, as is so often 

 the case with common sea-shore animals, is very meagre. 

 With the exception of Eichelbaum's* investigations into the 

 contents of the intestines of eleven examples of this Sea- 

 Urchin, varying from 17 to 48 mm. in diameter, t from the 

 North Sea, only minor notes on the subject are to be found 

 scattered sparsely through the literature relating to echinoderms. 

 It therefore seemed advisable to record the new observations 

 which are contained in the following paper. These observations 

 are based on the detailed notes which have daily been made by 

 me upon the behaviour of the Purple-tipped Sea-Urchins (some 

 sixty in number) which have lived during the last three years in 

 the marine aquaria at the Horniman Museum. The following 

 are the subjects which will be discussed : (1) Animal matter as 



* E. Eichelbaum, " tlber Nahrung und Ernahrungsorgane von Echino- 

 dermen," 'Wissench. Meeresuntersuch. v. d. Kommissionz. Wissen. Unters. 

 d. Deutsch. Meere in Kiel,' N. F., Band 11, Kiel, 1910, pp. 189-275. 



f Eichelbaum's measurements, and also those given by myself, are those 

 of the long diameters of the tests, excluding the spines. 



Zool. 4th ser. vol. XX., March, 1916. h 



