200 Dr. R. Greef on the Structure and 



animal is most fully extended, even under artificial com- 

 pression, and, indeed, then often most distinctly. This differ- 

 ence and the fact that we have only to do here with the above- 

 mentioned normal fine striation are of some importance, and 

 at least merit being specially indicated here. Stein, in his 

 most recent work on the Infusoria*, gives an interpretation of 

 these striae of the skin, with which, from my present obser- 

 vations, I cannot agree. Thus, after admitting, in correction 

 of his previously opposite opinion, the presence of muscles in 

 the Infusoria, founded upon W. Kiihne's investigations upon 

 the peduncular muscle of the Vorticellasf? he tliinks that, as a 

 complement to this, the cutaneous striae observed in many 

 Infusoria (especially the Stentors, Spirostomes, &c.) must be 

 interpreted as the body-muscles. It deserves to be indicated 

 here that this opinion was distinctly expressed by Ehrenberg, 

 who says (at p. 260 of his ' Infusionsthierchen ), in charac- 

 terizing the family of the Vorticellinse, " In some ( Vorticella^ 

 Carchesium^ Opercularia) longitudinal and transverse muscles 

 are recognized " ; and further (on p. 261), in the description 

 of the genus Stentovj " The organs of motion are the innume- 

 rable cilia of the surface, together with the frontal circlet of 

 cilia as a more special capturing organ. Visible longitudinal 

 striae of muscular fibres lie at the base of the longitudinal rows, 

 but at the front circular striae." Further, in the introduction 

 to the " Explanations of the class Polygastrica," he says : — 

 " Muscles can, however, be seen. These, in Stentor, distinctly 

 form the base on which cilia stand, forming cloudy longitudinal 

 striae or spirals, &c." From all these statements it is clear 

 that Ehrenberg regarded as muscles the same structures that 

 Stein has recently done, We can less distinctly learn from 

 them Ehrenberg's opinion as to the purpose of these muscles 

 — namely, whether they are merely regarded as body-muscles 

 which execute the contractions of the body, or as serving for 

 the movement of the cilia — which latter notion Stein justly 

 characterizes as erroneous with reference to our present know- 

 ledge of ciliary movement, whilst he at the same time points 

 out that in the Infusoria generally the striation of the body 

 and the ciliation stand in no causal connexion. The system 

 of striae of the Infusoria has also been interpreted by others in 

 Stein's way and more or less completely described, as by O. 

 Schmidt J, who has already expressly claimed his share in it, 

 and also by Kolliker§ and others. Excellent observations 



* Der Organismus der Infusionsthiere, Abth. ii. p. 23. 



t Arcliiv fiir Anat. &c. 1859, p. 824. See also the other important 

 memoirs on the irritability of the muscles &c. in the same volume, pp. 

 213, 314, & 748. 



X Archivfur mikrosk. Anat. iii. p. 391. 



§ Icones histiol. p. 14. 



