NOTES ON ECHINODERM MORPHOLOGY. 389 



corbeilles vibratiles du canal dorsal et les corps spheriques 

 des bras lui paraissent etre des organes des sens/' My only- 

 positive reference to the sacculi in this paper ^ was in the expla- 

 nation of fig. 1, which ran as follows. " s. Sacculi (' calcareous 

 glands' of Wy ville Thomson) of doubtful (? sensory) nature." 

 I put in the " ? sensory " in accordance with my father's sug- 

 gestion made three months previously. But I cannot see that 

 it at all justified Perrier in stating that the sacculi '' lui par- 

 aissent etre des organs des sens." 



His assertion that I took the same view of the ciliated cups 

 in the coeliac canal is entirely incorrect. All that I said of 

 them2 was that Ludwig had well compared them " to the 

 ciliated funnels on the mesentery of the Synaptidse." Further 

 on in the paper, however, I described how in certain pinnules 

 of Actinometra armata the radiating branches of the axial 

 cords '^ enter into connection with peculiar cellular organs, of 

 very similar construction to the groups of large epidermic 

 cells described in the tactile papillae of the integument of the 

 Synaptidse, by Professor Semper. I am inclined to regard 

 these organs also as sensory in function ; their position upon 

 the dorsal or most exposed side of the pinnules certainly 

 favours this hypothesis." Here then Professor Perrier, misled 

 by the double reference to the Synaptidae, has confused 

 together a variety of statements respecting entirely different 

 structures. 1. The ciliated cups in the coeliac canals of the 

 Comatulse. 2. The ciliated funnels on the mesentery of 

 the Synaptidse. 3. The cell-groups in the tactile papillae 

 of the Synaptidse. 4. The cellular organs on the dorsal side 

 of the ungrooved pinnules of Actinometra armata. I 

 attributed a sensory nature to the fourth of these, and he 

 describes my views as applying to the first. 



But even this is not the full extent of his errors. For on 

 the same page, in summarising my second paper of 1876, he 

 says, " Les corps spheriques (i. e. sacculi) y sent designes sans 



1 " Remarks on the Anatomy of the Arms of the Crinoids," ' Journ. Anat. 

 and Physiol.,' 1876, vol. x, p. 580. 



2 Ibid., p. 579. 



VOL. XXVII, PART 3. NEW SER. E F 



