ROOT-KNOT EELWORM. 



101 



With the few ales, however, this is quite diferevt (still continuing to 

 abridge from Prof. Atkinson's observations, it is noted) ; " the female 

 does not moult again, but continues to enlarge enormously until it is 

 gourd-shaped," see figures of this gourd- or pear-shape, p. 99 ; this 

 female gradually becomes filled with eggs and young larvfe ; and the 

 length of the life cycle is given by Prof. Atkinson as one month. 



In the very large amount of specimens of galled Tomato roots sent 

 me in the winter of 1892-93, 1 had good opportunity of observing these 

 peculiarly shaped Eelworms, and their contents, so far as could be 

 done with moderate microscopic powers, and their description, and 

 that of the galls on the roots, is given in my Eeport ; and later on, 

 towards the end of March, I was able also to examine the nature of the 

 root-knot galls, and the condition of the Eelworm tenants in galled 

 Cucumber roots, sent me by Mr. Hamilton H. Hurnard, from Gurney's 

 Manor, Hingham, Attleborough, Norfolk. 



Mr. Hurnard first wrote as follows : — " Last year I was very much 

 perplexed at the condition of my Cucumber roots ; no plant died, but 

 they were not a success. This year I have lost plant after plant." On 

 March 23rd, Mr. Hurnard forwarded me, for examination, two roots 

 of Cucumbers taken from a large pot at seven o'clock that same 

 morning, with the very just remark : " It is really heartrending to go 

 into my Cucumber house and see a plant or two dead every morning, 

 with Cucumbers of all ages on it." 



On examining the specimens sent, I found the galls on the roots were 

 very similar, both in position and appearance, to those described, on 

 Tomato roots, in my 16th Eeport, p. 131, and figured on the accom- 

 panying plate about two-thirds natural size; but the Eelworms within 

 them appeared to be not so far advanced as those in my winter 

 specimens. 



In these Cucumber galls there were many of the thread-like forrafs 

 of this Eoot-knot Eelworm, of different sizes, some exceedingly minute; 

 but I did not observe more than one instance of what might be a 

 developed female. In this case the pear- or gourd-shape was observ- 

 able, but the wormlet was rounded out at the base, that is, more of a 

 tulip-bulb shape, without the central depression being noticeable. 

 There were also one or two going through pupal changes. 



With regard to specimens of this Cucumber root infestation, which 

 I submitted to Dr. J. Eitzema Bos, Wageningen, Netherlands, for his 

 skilled examination, he was good enough to report to me on March 27th 

 as follows : — " In the galls I find different Nematoid worms ; Heterodera 

 radicicola, in different stadia of development, and some other Nema- 

 todes, which live in the decayed matter of the galls [Diplogaster and 

 Rhahditis species). Of the Heterodera radicicola, 1 found one completely 

 developed female, some males, and different stadia of the larvae, like 



