NOTES ON THE NAIDIFORM OLIGOCHiETA. 335 



Notes on the Naidiform Oligochaeta ; contain- 

 ing a Description of New Species of the 

 Genera Pristina and Pterostylarides, and 

 Remarks upon Cephalization and Gemma- 

 tion as Generic and Specific Characters in 

 the Group. 



By 



Alfred Gibbs Bourne, I>.Sc.(I<ond.), C.m.Z.S., F.I^.S., 



Fellow of University College, London ; Fellow of the Madras University ; 



Professor of Biology in the Presidency College, Madras. 



With Plates XXVI and XXVII. 



These notes were commenced at the instigation of Professor 

 Lankester in 1882, to whom the late Mr. Thomas Bolton 

 had forwarded specimens of a Naid which Professor Lankester 

 identified as the Nais littoralis of O. F. Miiller_, together 

 with another Annelid which I subsequently described as 

 Haplobranchus sestuarinus. 



Professor Lankester kindly placed in my hands all his 

 drawings and notes relating to Naids; and those on Nais 

 (Paranais) littoralis and Pterostylarides macro- 

 chseta, to each of which he had devoted considerable atten- 

 tion, are made use of in this paper. 



To Mr. Bolton I was indebted for a very large number of 

 Naids collected in all parts of England, and I had intended to 

 prepare a monograph on the British species of this group, 

 but I left England with a series of scattered notes and 

 half-finished drawings. Vejdovsky, in his magnificent 

 ' System und Morphologic der Oligochaeten,' brought to- 

 gether his own researches and a summary of our knowledge 



