1876.] On the Structure 0/ Antedon rosaceus. 451 



IV. Supplemental Note to a Paper * (l On the Structure, Physio- 

 logy, and Development of Antedon (Comatula } Ij<imk.) rosaceus. 33 

 By William B. Carpenter, M.D.j F.R.S. Received April 6, 

 1876. 



Since my conimunieation of the above-cited Paper to the Royal Society 

 on the 16th December, 1875, two important contributions to the Anatomy 

 of Antedon have appeared — one by Dr. Ludwig, chiefly based on his 

 study of Antedon Eschrichtii (" Zur Anatomie cler Crinoiden," Zeitschrift 

 f iir "Wissenschaftliche Zoologie, Bd. xxvi. 1876, p. 361, continued in Nach- 

 richten von cler Konigl. Gresellschaft cler Wissenschaften unci der Gr. A. 

 Universitat zu Grottingen, No. 5, Feb. 23, 1876), and the other by Prof. 

 G-reef, of Marburg (Sitzungsberichte cler Gresellschaft zur Beforderuug 

 der gesammten Naturwissenschaften zu Marburg, January 1876), both 

 of which seem to have been prompted by the appearance of Professor 

 Semper's short paper on the subject. These able observers fully concur 

 with me, as to all essential particulars, in the account I have given of the 

 triple canal-system of the arms, which M. Edmund Perrier not only 

 could not himself find, but ventured to predict that no one else would 

 find ; in fact, Professor Grreef's figure of a transverse section of an arm 

 might have been copied from one of the drawings I have had by me for 

 more than ten years, save for one slight additional feature. The G-erman 

 investigators also accept the correctness of the statements made by me 

 in my Pirst Memoir, that the "nerve" of Miiller is really the genital 

 rachis, and that Miiller's " vessel " in the arms is solid, not tubular, 

 though neither is disposed to believe with me that this " axial cord " is a 

 nerve. The character of a nerve, on the other hand, is assigned by 

 Ludwig to a fibrillar band lying beneath the epithelial floor of the ventral 

 furrow of the arms ; which band had been independently noticed by my 

 son, Mr. P. H. Carpenter f (who is at present working in the laboratory 

 of Professor Semper at Wiirzburg), in two of Professor Semper's Philip- 

 pine species, Actinometra armata and A. nigra, as also in Antedon 

 Eschrichtii, in which it had been previously discovered by Ludwig. It is 

 not nearly so distinct, however, in A. rosaceus ; but its existence in that 

 species was also independently recognized by Professor Huxley, who, 

 like Ludwig, was led by his general view of the homologies of the 

 Crinoids to regard it as a nerve. My son regards both the ventral band 

 of Ludwig and my "axial cord " as belonging to the nervous system, 

 being led to that conclusion, as regards the former, by its homology with 

 the radial nerves of other Echinoderms, and, as regards the latter, by 

 the very definite branching he has discovered in the axial cord of the 



* See antt, p. 211. 



t " Kemarks on the Anatomy of the Arms of the Crinoids," in the Journal of Anatomy 

 and Physiology for April, 1876, p. 571. 



