NERVO0S SYSTEM OP ANTEDON ROSACEUS. 513 



cord in the arms, dilates in the pinnules to form the genital 

 glands. The proximal or oral pinnules, i. e. those borne by 

 the Second Brachials, differ markedly from the others ; they are 

 longer than the rest, and habitually bend inwards, so as to arch 

 over and cover the disc ; they have no tentacles^ and no ambu- 

 iacral grooves, the ciliated epithelium of the grooves and 

 the subepithelial bands being both absent;'- they possess, 

 however, like the other pinnules, branches of the axial cords of 

 the arms. 



II. Historical Sketch. 



I propose, in this section, to notice briefly the principal 

 views that have been advanced concerning the nervous system 

 of Antedou. 



Midler/ in 1841, gave the first account of the genital rachis 

 in the arms of Antedon, but mistook it for the nervous system, 

 and described it as such; he also mentioned the axial cords, 

 but described them as vessels. 



In 1865 Dr. Carpenter, in his ' Memoir on the Structure, 

 Physiology, and Development of Antedon rosaceus,' cor- 

 rected Miiller's mistake concerning the genital rachis; and, 

 with regard to the axial cords, stated^ : '' It will be shown, in 

 the second part of this meitioir . . . that a system of branching 

 fibres proceeding from the solid cord that traverses the axial 

 canal of each calcareous segment of the rays and arms is trace- 

 able on the extremities of the muscular bundles, and reasons 

 will be given for regarding these fibres as probably having the 

 function of nerves, though not exhibiting their characteristic 

 structure." 



In 1872 Baudelot' called attention to the anatomical and 



1 Carpenter, ' Phil. Trans.,' 1866, p. 702. 



- P. H. Carpenter, " Remarks on the Anatomy of the Arms of the 

 Crinoids," part ii, ' Journal of Anatomy and Physiology,' vol. xi, p. 90. 



3 J. Miiller, "Ueber den Bau des Pentacrinus Caput Medusae." Physika- 

 lische Abhandlungen der Koniglichen Akadamie des Wissenschafteu zu Berlin. 



4 Carpenter, 'Phil. Trans.,' vol. 156, 1866, p. 705. 



° Baudelot, " Etudes Generales sur le Systeme Nerveux," ' Archives de 

 Zoologie Experiment ale,' tome i, 1872, p. 211. 



