Page:The Zoologist, 4th series, vol 1 (1897).djvu/378

350 The nerve-cord shows a tendency to enlargement between segments III.–IV. and the brain is pear-shaped with a rounded or convex hinder margin. There is a large head-pore between the prostomium and the first segment, and through this the cœlomic fluid and other floating materials from the body-cavity and head are poured out when a little pressure causes inconvenience to the worm.

The question naturally arises, Can this be the same as Michaelsen's Silver Worm (E. argenteus), found on the shores of the Elbe, or not? Unfortunately I do not possess the author's pamphlet, and the digest in Mr. Beddard's monograph is too brief for a decision. The descriptions correspond as far as they go, but I have not been able to verify the account of the nephridia, nor are we told in what way the setæ are disposed, or what the habits of the Elbe species are. In any case the species is new to Britain, and its predatory character raises the serious question—What is the best thing for the flower-grower to do if he finds them attacking his asters?

is the drastic one of pulling up every plant which shows signs of sickness and consigning it instantly to the flames. It might be possible to save some plants by carefully cutting out the roots which appear to be affected; but the operation would have to be performed the instant there were signs of failure, it would have to be conducted with the greatest care and delicacy, and there would still be two risks. Either the plant might succumb to the treatment, or the disease might reappear owing to the eggs of the worm having been left in the roots. The eggs are so minute that even the microscope would be of little service in their detection after they had once been extruded.

There is no doubt but that many of our minute annelids are parasitic. Heretofore, however, we have heard little of their ravages. The reason is probably to be found in the fact that so little was known formerly of annelid anatomy that when a worm was discovered its description lacked scientific precision, and so the different parasitic worms remained uncatalogued and unknown.