70 INLAND FISHERIES. 



trace of regeneration in them. On May 11 several arms were taken 

 off at the usual line of detachment, and kept alive in the aquarium 

 until June 9, when they showed no sign of regeneration. One of 

 these was still alive on June 25, and at that time was apparently 

 enjoying good health, and would turn over if put on its back. It 

 had lived, therefore, for over six weeks, but showed no sign of re- 

 generation. 



Another experiment was started on August 15 ; two arms were 

 taken off from each of four specimens. The rate of regeneration 

 of these specimens is given in the tables on page 65. On Sep- 

 tember 10, nearly three wrecks afterward, five of the single arms 

 were found alive, but showed no reg-eneration. On September 5 

 the new growth in the arms regenerating from the disc was from 

 8 to 5 mm. On September 2G, six weeks after the operation, one 

 of the single arms was found alive (7 mm.) It had not shown any 

 traces of regenerating a new arm, although it had healed. This 

 arm is represented natural size in Fig, 24, B, and the new growth 

 which took place on one of the stars from which these arms were 

 detached is shown in Fig. 24, A. Similar experiments were tried 

 last year with the same result. In a recent article by Miss Helen 

 Dean King, in Eoux' Archiv, it is stated that single arms were 

 kept alive for two weeks, but never showed signs of regeneration. 



Several experiments were carried on to determine what re- 

 generation would take place if the disc were cut through. On 

 May 11, nineteen specimens about 2^ inches in length were treated 

 in the following manner : Two arms were pulled off, and at the base 

 of one of the arms a piece was cut out from the top of the disc in 

 the manner shown in Fig. 26, These specimens Avere placed in a 

 large car at Woods Hole without food (except what could be 

 carried in the water). On June 9 there was a trace of regenera- 

 tion in some of the arms. On June 25, a little more than six weeks 

 after the operation, all the arms were growing out anew, and 

 varied from a mere trace of a new arm with the terminal eye-spot 

 (which always shows first) to arms ^ inches (about 7 mm.) long. 

 This experiment shows two things: that the new arm will re- 



