78 C. F. MARSHALL. 



and to be homologous with the intracellular networks which have 

 been described in other cells. It is evident from Fig. 6 of his paper 

 that we have to do with a true network and not a honeycomb, a fact 

 which is not so apparent from the figures of Eetzius and Bremer. I 

 have reproduced the figure from Melland's paper (Fig. 18). 



Melland's results were obtained partly in conjunction with 

 myself, and the object of the present paper is a continuation of this 

 investigation. I have endeavoured to trace the distribution of this 

 intracellular network of the striped muscle-fibre in the animal king- 

 dom, and also, as far as possible, to determine its function. 



The striation of muscle must not be confounded with a trans- 

 versely striated appearance caused by a corrugated outline of the 

 fibre, possibly due to a state of over-contraction. Such a false 

 striation is met with occasionally in some fibres in Echinus, 

 Hirudo, etc., and is the cause of the muscles of these animals having 

 been described as striped. I shall, therefore, only describe muscle 

 as being striped when the striation is due to the presence of the 

 intracellular network described by Eetzius, Bremer, and Melland. 



I have examined muscle taken from representatives of the chief 

 groups of the animal kingdom with the special object of investi- 

 gating the presence of an intracellular network in the muscle-cells, 

 either such as that of the striped muscle-fibre, or, when this does 

 not exist, an intracellular network of any kind. 



Amoeba and Hydra have been included in this investigation; 

 for it is an important point to determine the existence of an intra- 

 cellular network in such a primitive and eminently contractile cell 

 as Amoeba : it is also important to investigate the structure of 

 the muscular processes of the ectoderm cells of Hydra, as they 

 are supposed to represent the first beginning of a muscle-cell. 



In all cases the outlines and main details of the figures were drawn 

 with the camera ; in most cases under the yjjth immersion objective 

 of Beck with No. 2 eyepiece, giving a magnifying power of 1,100 

 diameters. 



Methods of Preparation. — The chief method of preparation used was 

 the method of gold staining employed by Melland. The gold stains 

 and renders evident the intracellular network of most cells, especially 

 the network of the striped muscle-cell ; hence it is at once a test 

 whether the striation of the fibre is due to the presence of the 



