206 Dr. R. Greef on the Structure and 



fibres*. But is it not more natural to regard the dark trans- 

 verse lines as having been produced by the granules being pushed 

 together by pressure during the contractions, which are often 

 sudden and strong, towards the crests of the transverse ridges 

 or tubercles, and here grouped in more or less regular streaks ? 

 Moreover it is to be borne in mind that the transverse streaks 

 in question make their appearance, especially in the anterior 

 part of the body, in the neighbourhood of the peristome. Here, 

 however, actual circular lines run round the whole body, per- 

 haps representing special circular muscular fibres. We can 

 therefore find nothing to justify us in regarding the broad 

 striae in question as muscular substance. It seems much more 

 feasible to regard them as a part of the so-called cortical layer 

 of the Infusorian body, which envelopes the muscles and other 

 organs and fixes them in their places ; to its signification in 

 the Infusorian organism we shall revert more in detail hereafter. 

 Moreover, for the granules made use of by Stein in his theory 

 we have a purpose, which has already been pointed out, and 

 seems to me to be satisfactory : they are the hearers of the blue 

 colouring -matter which renders the Stentor cceruleus immediately 

 recognizable, especially in the midst of the usually predominant 

 society of the green Stentor 2)olymorphus. They are, there- 

 fore, as Stein himself states, j!>i]9rHie7i^-(/ra?iit?es situated beneath 

 the cuticula ; and just as little as this property can be denied 

 to them does it seem to me that any other one has been demon- 

 strated for them. 



Let us now turn to the second system of strige, which run, 

 in the form of clear narrow lines, alternately with the strise just 

 referred to, and, like these, along the whole length of the body, 

 and which, as has already been explained, are regarded by 

 Stein as the connective substance of his muscular streaks. 

 They certainly at first produce the impression of clear, groove- 

 like, cutaneous strige which are stretched out between the dark 

 streaks ; but on more careful examination we find that beneath 

 each of these clear lines runs a poioerful hyaline thready which, 

 as we may ascertain most decidedly, can never be the expresssion 

 of the " cuticula folded in like a groove." This is characte- 

 ristically shown, in the first place, by the tortuosity of the thread 

 in a state of repose already described by Lieberkiihn, and 

 which is particularly beautifully seen in the hinder part of the 

 body. Against this Stein urges that the same thing occurs 



* Stein has overlooked the fact that this transverse striation, to which 

 he gives so much prominence, has been ah-eady observed and ilhistrated 

 by Kolliker, with a figure (Icones histiol. p. 14, pi. 1. fig. 12), which leaves 

 no doubt that Kolliker had before him exactly the same phenomenon as 

 Stein. 



