( 259 ) 



NOTES FROM THE MILLPORT MARINE BIOLOGICAL 



STATI0N. 



By Richard Elmhirst, F.L.S. 



In 'Materials for the Study of Variation' (1894), Professor 

 Bateson has brought together many instances of variations or 

 abnormalities of Echinoderms. Since the publication of the 

 above, numerous other instances have occurred, and at the Mill- 

 port Station we have specimens as follows : — 



Mbristic Variation in Asteroids. 



Astropecten irregularis. — One specimen with the third ray 

 divided. 



Porania pulvillus. — Two specimens, both symmetrical, with 

 only four rays. One of these (fig. 2) was obtained in June, 

 1912, and lived in captivity for nine months. 



Stichaster rosea. — One specimen with the third ray divided 

 almost from the disc. 



Cribella oculata. — One specimen with the fourth ray divided 

 (Robertson collection). 



Solaster papposus. — One specimen with the eleventh ray (out 

 of thirteen) divided, and another (fig. 3) with the fourth and 

 seventh rays (out of thirteen) divided. Number of rays varies 

 from ten to fifteen. 



Solaster endeca. — One specimen with only six rays (fig. 4) 

 (Robertson collection). Number of rays is usually eight to 

 thirteen. 



Asterias rubens. — One specimen (unfortunately lost) with six 

 rays, and another with seven rays (fig. 1). 



Asterias glacialis. — One specimen with six and another with 

 seven rays (Robertson collection). A third had a small arm at 

 right angles to a ray, as in the Cribella oculata mentioned by 

 Bateson, loc. cit. p. 440. This specimen has been handed over 

 to Dr. J. F. Gemmill for further investigation. 



x2 



