212 Dr. W. B. Carpenter on the Structure [Jan. 20, 



formation), but had also investigated their structure to an extent suffi- 

 cient to enable him to recognize the erroneousness of many of the state- 

 ments put forth by Prof. J. Miiller in his celebrated Memoir of .1841, 

 'Ueber den Bau des Pentacrinus Caput Medusas? which has been the 

 principal authority as to the structure of the Crinoidea for all subsequent 

 writers of zoological text-books. I then placed before Dr. Semper not 

 only the already published First part of my Memoir, but also the materials 

 I had collected for the Second ; and finding that my main conclusions 

 agreed completely with those at which he had arrived, he most kindly 

 offered to hold back the publication of his own views until I should have 

 given mine to the world. Having been subsequently appointed to the 

 Chair of Zoology in the University of Wurzburg, Prof. Semper has of 

 course taught to his students what both he and I regarded as the truth 

 of many things erroneously viewed by J. Miiller ; and another investi- 

 gator, M. Edmund Perrier*, having in the meantime entered the field, 

 and reproduced some of Midler's errors, Prof. Semper has thought it 

 right to give a wider publicity to his convictions on the subject, which 

 my own protracted delay fully justified him in doing. " In the year 

 1868," he says, " I was intending to publish a short memoir on that 

 which I had found, when, becoming acquainted in London with Dr. Car- 

 penter, I was delighted to learn that that able observer had obtained 

 exactly the same results on European as I on Philippine Comatulce. In 

 the expectation that the English investigator would soon publish his 

 already prepared work on the Crinoidea, I deferred till now the com- 

 munication of the results of my examination : but since, after five years 

 waiting, there is imminent risk that from my lectures the results of 

 Carpenter's and my own toilsome investigations may somehow find their 

 way into publicity, I hold that the moment has arrived to break the 

 silence I have hitherto kepf'f. Eor the same reason I think it desirable 

 to place on record without further delay the general results of my own 

 investigations, with such illustrations as may render my descriptions 

 intelligible — though I have reason to hope that the time may not be far 

 distant when I may be able to present to the Royal Society the Second 

 Part of my Memoir, giving with the First such a detailed account of the 

 Structure and Life-history of this type as may serve as a basis for the 

 description of the Pedunculate Crinoids known as living types. Of these 

 I have already examined two of the "West-Indian species of Pentacrinus, 

 with the P. Wyville-Thomsoni (of which several specimens were obtained 



* Archives de Zoologie Experimental, torn. ii. 1873, pp. 29-86. — This observer has 

 confined himself to the study of the arms, examining their terminations as transparent 

 objects. In this manner he has added much to our knowledge of their Histology ; but, 

 through not having examined transverse sections of the arms and pinnules, he has not 

 only failed to recognize the true tentacular canal, but has been led to affirm that there 

 is only one canal-system in the brachial apparatus. 



t Ann. & Mag. Nat. Hist. Sept. 1875, p. 202. 



