76 0. F. MAESHALL. 



end or laterally (as Calberla^ states), because the fibres of 

 trout muscle examined were evidently single cells, and liad the 

 network well developed. It is difficult to conceive that these 

 become fitted together, either end to end or laterally, so that 

 the network of one cell should exactly fit on to that of the 

 next. 



4. The network develops centripetally, and commences at the 

 part of the cell farthest away from the nucleus ; moreover, it 

 does not appear to become connected with the nuclei till the 

 fibre is fully developed. 



Haswell,^ from his observations on the muscle of the gizzard 

 of Syllis, forms a view of the ontogeny of striped muscle which 

 does not agree with that described above. 



In the same organ, in various species of Syllis, he finds in 

 one case bundles of non-striped fibres ; in another, compound 

 hollow striated fibres, consisting of bundles of fibrils similar to 

 the above, and bound together by a single transverse network. 

 In a third there are three transverse networks, and so on up to 

 the fully developed type of striped muscle found in Vertebrates 

 and Arthropods. He therefore regards each striped fibre as 

 derived from a bundle of non-striped fibres. He thinks the 

 transverse network probably the equivalent of a transverse 

 line of nuclei of the unstriped fibres, which occupies a similar 

 position. 



If this is correct each striped fibre must be a multicellular 

 structure, and the network intercellular, and not intra-cellular. 

 However, in another part of his paper he speaks of each fibre 

 being formed from a single cell, the nucleus of which divides and 

 forms " a multinucleated protoplasmic body, by modification 

 of whose protoplasm the muscle- substance and networks are 

 formed." 



1 ' Arch. f. mik. Anat.,' xi, 1875. 

 ^ Loc. cit. 



