204 Dr. R. Greef on the Structure and 



body-striae is analogous to the sarcolemma of the muscular 

 fibres. 



From the above it will be seen that the question about the 

 muscles of the Infusoria is answered by Stein in great detail 

 and very definitely ; and if the answer were correct we should 

 have made an essential step forwai'd in the knowledge of the 

 organization of the Infusoria. But my observations compel 

 me to advance doubts with respect to the main points in 

 Stein's statements. If we examine Stentor cceruleus, which is 

 justly recommended by Stein for investigation with regai'd to 

 the question before us, we see without any trouble the well- 

 known regular longitudinal striae running from before back- 

 ward over the whole surface, and, indeed, alternately a very 

 narrow, pale, and perfectly liomogeneous stria, resembling a 

 pale line ox furrow drawn along the whole length, andi abroad 

 ribbon-like stria, in which many fine granules of various sizes 

 are scattered, and which consequently, in contrast with the pale 

 striae, acquires a cloudy appearance. The broad cloudy bands 

 thus appear to be enclosed and shut off" from each other by the 

 pale threads. According to Stein's view, above explained, the 

 former represent the true muscles, whilst the pale lines are 

 merely non-contractile connective substance, the cement 

 which unites the muscular strise with each other. 



To me, however, all the characters seem to speak in favour 

 of the reverse condition — namely, that the narrow pale striae 

 are the time muscles, and the broad cloudy bands form the 

 connective substance. Lieberkiihn* has already expressed 

 this opinion with regard to the body-sti-ise of the Stentors ; and 

 the observations cited by him in support of it are so con- 

 vincing that it cannot but appear sui-prising that Stein should 

 briefly, and without sufficient reasons against them, set them 

 aside for the benefit of his own theory. Lieberkiihn, after 

 mentioning the broad richly granular strise of the Stentors, al- 

 ready described by Ehrenberg, says : — " But there is yet an- 

 other system of striae which behave like muscles, inasmuch as 

 they are endowed with the property described by Edward 

 Weber as belonging to muscles — -namely, that in a state of re- 

 pose they acquire a serpentine form, and extend themselves 

 straight during contraction. They are sharply contoured 

 fibres, free from granules, of about the breadth of the non- 

 granular interspaces, beneath which they run in the direction 

 of the long axis of the body ; they are attached in front below 

 the great circlet of cilia, and behind at the ' sucking-disk ; ' 

 some of them unite during their course. The changes occur- 



* Archiv fiir Anat. &c. 1857, p, 403, note. 



