THE BLOOD-CORPUSCLES OF THE ANNELIDES. 483 



of the Oligochaeta rather than one of the Ilirudineae. I submit, 

 therefore, that I am justified in saying that my readers, on finding 

 the word 'Annelides' used once on a page in which the word 

 'Annulata' is used several times, might have been expected to 

 suppose that the former word was not used in the same sense as 

 the latter ; and the more so as this different and restricted sense is 

 the very sense in which it is used by both Leuckart (' Menschlichen 

 Parasiten,' p. 155, 1863) and Gegenbaur ( f Grundziige,' p. 159, et 

 alibi, 1870), the two authors to whose pages I had most constantly 

 referred. 



I will now ask the reader to refer to a somewhat wider context, 

 and, turning to a note on p. 138, to observe that there, in opposition 

 to the nomenclature of the two last-cited authorities, and also of 

 De Quatrefages, I argue at some considerable length in favour of 

 connecting the Hirndineae with the Annelides. The Introduction 

 to my book was written after the other two parts; and in the 

 corrected proofs now before me, I find that I have, it may be 

 charitably supposed with a view of saving the student from con- 

 fusion, throughout the part in question altered the word 'Annelides,' 

 which I had written and had before me in print, to ' Annulata' 

 whenever it had been intended to be used in the wide sense in 

 which Lamarck, Milne-Edwards, Grube, and Leydig use it, and 

 I myself, as the note in question proves, should have preferred to 

 use it, and indeed do use it, at pp. \ii, 135, 138, so as to include both 

 Discophora and Chaetophora. I do not blame my readers for not 

 having consulted printed proofs which were not accessible to them ; 

 persons, however, to whom an inner conviction of their own accuracy 

 may be dear in the face of adverse criticism, may learn from this the 

 advisability of preserving such documentary evidence as that to 

 which I have here referred. 



Leaving now the very wearisome and somewhat unprofitable task 

 of self-vindication, I will now proceed to point out that several of 

 Professor Lankester's statements are in opposition, not only to the 

 authorities, but also to the facts of the case. 



The first of these statements with which I will deal is to the 

 effect that — 



1 The vascular fluid of Branchiobdella notoriously differs from the vascular fluid of 

 true leeches, in that it most certainly does not communicate with the perivisceral 

 cavity so as to form a lacunar circulation? 



1 i % 



