344 I^r. I'lnn/ T.iAv on <i new 



was also observed 1)v J)r. Kiilm in tlie case oi AnguiJhila 

 Jipsaci. 



1 have hitherto met \\\\\\ the (Itloriuatioiis ])ro(hu'ed hy 

 the Aii_uiiinuli(k> under coiisideraticii on tlie leaves of Achil- 

 lea vii//i foh'uitij only in some ])arts of the Pfalzantiial in 

 the Wienenvald, and always only in very small numbers. 

 Whether the whole jdant is injured by it I could not ascei'tain, 

 as 1 have always found it oidy upon the leaves of isolated 

 jilants of scanty growth standing upon ])oor soil, never upon 

 strong and luxuriant j)lants. 



The Anguilluhv themselves agree exactly in their ])rincipal 

 characters with the other known forms infesting plants. The 

 onlv specific dirterenccs are derived from the size and colour 

 of the body, and the })roportions of its parts to one another. 

 But before indicating the specific characters of the inilfoil- 

 Anguillula, I will give an accurate description of it. 



The Anguillula^ of the milfoil have an elongated body, 

 attenuated towards tlie two ends, round in transverse section, 

 and of undecided colour. They may be said to be translucent 

 whitish with a gi-eenish yellow shimmer. This shimmer, how- 

 ever, appears to proceed from their food, which in all proba- 

 bility consists of the above-mentioned greenish yellow Huid 

 contained in the galls. By transmitted light the body is seen 

 to be entirely filled with granules of difterent sizes and forms, 

 which prevent any examination of internal organization. Tlie 

 external integument of the body is rather thick, (juite smooth, 

 and shining. In the middle of the anterior, obtusely rounded 

 end of the body is the mouth, which is continued within into 

 the oesophagus, Avhich runs straight for a very short distance, 

 and at a distance from the mouth equal to the transverse 

 diameter of the body at the same S})ot presents a globular 

 muscular dilatation. From this it runs backward in an in- 

 distinctly visible tortuous line, and at the second curvature 

 loses itself entirely in the granular contents of the body. In 

 AnguilluJa dipsaci Dr. Kiihu observed that the portion of the 

 oesophagus situated behind the globular dilatation was also 

 somewhat tortuous, and j^resented at its extremity a second 

 similar dilatation, Avhich I could not detect in the Anguillula 

 of the milfoil. The other AuguiWuWdsn {e. g. A. Jin viatilis, 

 aceti, (/hitinis^ inucronata, Imea,&c.) ])0ssess similar rounded 

 muscular dilatations of the oesophagus*. 



The posterior extremity of the body is rather ra])idly atten- 

 uated, and terminates in a much finer point than the anterior 

 end. Prof. Grube has already indicated that all Anguillulai 



• Grube, "Ueber einipe Anguilliilen, und die Entwickhinfj vod Gordius 

 uqmtk-m," iu Arch, fur Naturg. Jalirg. xv. (184!>), p. 358. 



