54 eelwokms. 



large numbers of wliat, I think, is Tylenehus devastatrix. This species 

 I find nearly always present in the diseased plants (as well as Uetcro- 

 dera in the finer rootlets), but is, so far as I have yet made out, 

 confined to the thicker parts of the root, and in the cortex close up to 

 the bast in many instances. Where they were present the root does 

 not grow mvich in thickness, except very irregularly. I hope you will 

 be able to get a glimpse of this Ti/Ienchus, I have forwarded another 

 piece to Dr. Eitzema Bos for identification. This morning I casually 

 found larvffi, eggs, and adults in the root, but this was a chance." — J. P. 



In reg.irJ to the effect on growth, Prof. Percival remarked that the 

 most characteristic symptoms of the disease were to be found in the 

 leafage, and as I had not the opportunity myself of securing specimens, 

 and he was not at the time in Kent, he was good enough to forward 

 me a few dried leaves showing the peculiar conditions he noted as 

 accompanying attack ; with the mention that he had investigated the 

 anatomy of the leaf carefully, and found some interesting points, which 

 lie would explain later. 



These foints, and an account of Jds observations, are, I believe, to be 

 [liven by Prof. Percival in the next part of the Journal of the Puji/al 

 Agricultural Society, to be published on January 1st, 1895 ; but I was so 

 desirous to include some reference to this interesting observation in my own 

 report of the observations of 1891, that I requested and obtained permission 

 from Prof. Percival to include ivhat he had himself communicated to me in 

 my notes now [November, 1891) prepariny for my next Annual Report. 

 For this I feel greatly obliged. 



In my own examination of the thick roots placed in my hands by 

 Prof. Percival, I found narrow anguilli-form Eelworms in the white 

 part below the external bast, which certainly greatly resembled the 

 Tylenehus devastatrix, but I could not by any means feel certain whether 

 they were of this speaies, or of the H. schachtii in larval or male state, 

 therefore I laid my difficulties and specimens before Dr. Eitzema Bos, 

 and append, with many thanks, a part of his valuable replies, as (with 

 the reference to the figures also given) they may be of great service to 

 other enquirers. 



Dr. Eitzema Bos observed: — "I found in the larger parts of the 

 roots which Prof. Percival sent me, in the cortex close to the bast, 

 Nematoid-worms closely allied to, if not identical with, Tylenehus 

 devastatrix. I never found 2\ devastatrix in roots, always in stems and 

 leaves (also in subterranean caulomata and phyllomata). . . . The 

 Tylenehus in Humulus roots is somewhat smaller than T. devastatrix, 

 but as this species varies much in length, that would be no cause why 

 it should not be devastatrix.'" 



Precise maximum and minimum measures of length of male and 



