112 The Irish Naturalist. May, 



1898, the second form entirely predominated, and E. parvulus 

 was nowhere to be found. The strange fact is, that though I 

 made memoranda and drawings at the time, but did not 

 publish an}- note on the subject, these same two worms 

 appear in equal numbers in the material sent me from 

 Ireland. This is a most remarkable coincidence. Doubtless 

 here again E. parvulus led the wa}^ In January two forms 

 were at work in equal numbers, and one may expect that by 

 March parvulus will have disappeared, and the larger form 

 be in supreme possession* Until I have time, and fresh 

 material, I do not propose to name the second form, or 

 attempt to identify it, though I have some curious memoranda 

 and drawings which will throw light on its history among 

 the material I have been collecting in former years. I want 

 now to call attention to a new theory which I formulated 

 four years ago, and which the Irish discovery tends greatly 

 to confirm. 



II. — On a Ne;w The^ory of I^arvai, Forms among 



THE lyOWER ANNEI.IDS. 



in my note-books I find the following memorandum under 

 date March, 1898, accompanied by a drawing : — " NoTE- 

 Some weeks after discovering E. parvulus I again examined 

 the celery, and found this worm (drawn by the side) in its 

 place. I at once questioned whether E. pai'vulus may not be 

 what one might call a larval form. I^arvse of gnats lay eggs ; 

 why may not worms, and then develop into higher forms ?" 

 A little later I added another note; then, owing to my 

 removal from the neighbourhood of Birmingham, the work 

 was laid aside, and no further opportunity occurred for 

 carrying out the necessary research. Now, the surprising 

 point lies here. The diseased celery from Ireland is infested 

 with identically the same two worms as destroyed my trench. 

 I have not heard of any one having seen the second form in 

 Great Britain. I have not myself described it in connection 

 with celery or aster sickness, nor am I aware that anyone, 

 either here or elsewhere, has observed the phenomenon. 

 How is it, then, to be accounted for, that when the Aster 

 Worm, whether in England or Ireland, in 1897 or 1902, 

 attacks celery, it is iound to be attended by another form of 



