(r(tU-j)roduciiKj AiKjnillnl idi'. 347 



.'uul pu.shill^• abniit ; and uii the other, when dead, although 

 tliey may lie straight, they may always be uiuhily extended 

 or contracted, which with such small individuals may easily 

 cause a difference of 0*1 millim. or even more. The young 

 Anguilluhe not yet sexually mature, which always occur asso- 

 ciated with the fully developed and sexually mature individuals, 

 and indeed in greater number tium the latter, are of very dif- 

 ferent lengths according to the degree of their development. 

 in the form of the botly they resemble the sexually mature 

 individuals ; only the granules and vesicles of the contents of 

 the body are larger. 



The (t^^^ is about twice as long as broad, equally rounded 

 at the two ends ; its contents are finely granular, with several 

 vesicles scattered through them. Some time before liatching, 

 the young Anguilluhe may be seen through the delicate mem- 

 brane of the ^^^. They lie elliptically curled up in the <i^'^^ 

 following the form of the latter. When hatched they are about 

 five times as long as the t.^^^ or about one fifth of the length 

 of the adult*. The circumstance that we almost always find 

 together all the stages of development of the Anguillula of 

 the milfoil, from the egg to the egg-laying individual, may 

 be explained by supposing either that in this species several 

 generations follow one another during the favourable season of 

 the year, or that the oviposition takes place at very various 

 times, as, indeed. Dr. Kiihn supposes to be the case with 

 A ng n illu la dipsac ?'. 



The mode of life of the milfoil-Anguillula probably re- 

 sembles exactly that of A. dipsaci^ Kiihn, A. tn'tici, Koff., 

 and other Anguilluhe of plants. The young asexual Anguil- 

 luhe winter in the leaf-galls ; or the last-deposited eggs may 

 winter outside the galls ; and in the spring, when the galls are 

 already rotted by the moisture of the soil, they quit them, 

 creep upon the young shoots of the milfoil, bore into the still 

 tender tissues of the expanding leaves, and produce u]:)on them 

 afresh the galls described at the commencement of this paper, 

 in which they become further developed, and give birth to 

 new generations. Towards autumn the original abundance of 

 sap in the galls is gradually exhausted, their green colour 

 passes to yellow ; finally they become withered and wrinkled ; 

 and the individuals contained in them, which have never 

 quitted the gall, stiffen or become dried up at the beginning of 

 the cold season, to be awakened again from this apparent 

 death only by the sunshine of spring. 



* 111 the viviparous Anguilliilicl;e, sucii iis Aui/idllitla aceti, ghitinis, 

 fixviatUis, Sec, tlie young are born still enclosed in the egg-membranes. 



