59 



terms : «... It will be shown in the Second Part of this Memoir that, be- 

 sides the so called »ambulacral« canal with its tentacular extensions, 

 each arm and each pinnule contains an afferent and an efferent canal, 

 in which the nutritive fluid is exposed to the aerating influence of the 

 surrounding medium. a Perrier's comment on this passage is that he 

 has been unable to find these afferent and efferent canals, and he attri- 

 butes Dr. Carpenter's description of them to an error of observation; 

 while on p. 73 he goes so far as to say of one of them that »nous de- 

 meurons convaincu que personne ne le reverra(f. 



He now admits his error, however, but attempts to excuse himself 

 for having committed it in a way which only makes matters worse. He 

 says that the thin-section method was comparatively unknown in France 

 at the time of his work, and that Dr. Carpenter me disait pas, dans 

 son mémoire, avoir fait de coupes dans les bras de la Comatule'''. This 

 is a singularly unfortunate excuse; for on page 719 of the text Dr. 

 Carpenter described the appearances presented by the horizontal 

 and vertical longitudinal sections of the decalcified arm which he repre- 

 sented in pi. XLHI, figs. G and 7 ; and the explanation of fig. 2 on the 

 same plate commences »Transverse section of a decalcified arm«. Dr. 

 Carpenter's preparations, now over twenty years old, were not the thin 

 transparent sections of the more recent zoological work. They were 

 merely slices of the decalcified arm, cut with a sharp knife or a pair of 

 fine scissors; and ifPerrier had simply taken the trouble to cut a 

 piece of arm in two with a scalpel, he could have convinced himself 

 at once, as he has since done, that Dr. Carpenter's description of the 

 two lower arm-canals was correct. I could mention other errors con- 

 tained in his criticisms of Dr. Carpenter's work; but those which I 

 have exposed are sufficient for my present purpose. It does not seem 

 to have occurred toM. Perrier, who was then a young and unknown 

 man, that Dr. Carpenter would not have been likely to make such 

 very definite statements without having good reason for them. If 

 Perrier had contented himself with simply saying that he had been 

 unable to find one of the structures described by Dr. Carpenter, no 

 harm would have been done ; but with the easy confidence of his in- 

 experience, he took upon himself to say that he was convinced that no 

 one else would ever do so in future. This was a scarcely courteous 

 mode of referring to the work of a man who had achieved a European 

 reputation before M. Perrier was born; but more than two years 

 passed before Dr. Carpenter took any public notice of these errors. 

 On January 20, 1876 he presented to the Royal Society an abstract 



5 Nouv. Arch, du Mus. Hist. Nat. T. IX. p. 91. 



