206 Dr. W. B; Carpenter on the 



describes, though not clearly) *, since the body-cavity and con- 

 sequently also its prolongations are supposed to be separated 

 from the vascular system. His attack on Miiller and Carpen- 

 ter therefore fails, since he finds again the same parts as they, 

 and only arbitrarily changes the name and interpretation. 

 Moreover he is positively behind them both : he denies the 

 existence of the nervous system described by Miiller {I. c. p. 83) ; 

 yet it is present, though it was erroneously interpreted by its 

 discoverer. The only really new information given by Perrier 

 is concerning the fibrous band situated above the tentacle-canal 

 (I. c. p. 55, pi. iii. f. 8, m), with which I am also acquainted, 

 and which, as mentioned above, will probably prove, on closer 

 histological examination of living animals, to be the nervous 

 system that for the moment is yet to be sought. 



Addendum by Dr. Carpenter. 



The full justice which my friend Prof. Semper has obviously 

 desired to do me, in speaking of my conclusions in regard to 

 the structure of Comatula, as having been arrived at inde- 

 pendently of, and contemporaneously with, his own, might 

 seem to render it quite unnecessary for me to put forward any 

 claim to a discovery which has, I think, many bearings of 

 great interest, physiological as well as morphological. But 

 he seems to have overlooked the fact that I had not only 

 distinctly pointed out what I believe (in common with him) 

 to be Prof. Miiller's errors, but had indicated what I regard as 

 the true Nervous System, in the First part of my "Researches 

 on the Structure, Physiology, and Development of Comatula 

 rosacea" communicated to the Royal Society in 1865, and 

 published in the ' Philosophical Transactions ' for 1866. 



After describing (par. 19) the muscular apparatus of the arms, 

 I say : — " It will be shown, in the Second part of this memoir, 

 that the cord which traverses the length of the arms between 

 the canal just mentioned and another canal which overlies it, 

 and which was regarded by Prof. Miiller as a nerve, really 

 belongs to the reproductive apparatus. But it will also be 

 shown that a regular system of branching fibres, proceeding 

 from the solid cord (described by Prof. Miiller as a vessel) that 

 traverses the axial canal of each calcareous segment of the rays 

 and arms, is traceable on the extremities of the muscular bun- 

 dles ; and reasons will be given for regarding these fibres as 



* This follows indubitably from bis remark (p. 49), "the general cavity 

 of the body is continued beneath the tentacular canal." 



