1903. 



NATURAL SCIENCES OF PHILADELPHIA. 



351 



May 19. 

 The President, Samuel G. Dixon, M.D., in the Chair. 

 Twenty-one persons present. 



Regeneration of the Body of a Starfish. — Miss Sarah P. Monks, in a 

 note read to the meeting, stated that it had been known for many years 

 that starfish can renew rays that have been removed. " It has been 

 stated that in certain starfishes an arm itself can produce a new star- 

 fish — Haeckel, Sarasin, von Martens and Saris — but this has been denied 

 by other observers. "^ It is beheved by some that a portion of the disk 

 must remain if there is any regeneration, and the breakage plane is near 

 the body, or disk, in cases of renewal of arms. 



In studying regeneration of Phataria {Linckia) fascialis she had cut 

 arms at different distances from the disk, and a number of the single 

 rays produced new bodies. The free ray made a new body and the 

 rest of the starfish produced a new ray, and there was very little differ- 

 ence in the rate of growth of each, and no definite place for breaking. 



In the photograph of a six-rayed Phataria, the cut ray attached to 

 the body shows a small ray sprouting, while the free ray shows four 

 new rays. This was cut July, 1902, and the photograph taken Febru- 

 ary, 1903. 



The manner of growth is as follows: The cut edges heal and draw- 

 down toward the oral side of the starfish, then small knobs appear at 

 the end which grow into rays in which the ambulacral furrow soon 

 appears, wdth the small mouth in the center of the rays. 



She had collected specimens at San Pedro, Cal., showing all stages 

 of growth of the single arm, from the recently broken arm to those like 

 the photograph on through all sizes of growing rays. 



The following have been accepted by the Publication Committee 

 and ordered to be printed : 

 ^Regeneration, Morgan, p. 102. 



