OBSERVATIONS ON STRIPED AND UNSTRIPED MUSCLE. 83 



showing fine longitudinal fibrillation. In the Holothurians he 

 describes the muscle as non-striped, but states that longitudinal 

 fibrillation is to be seen in it. 



Vermes. 



Riruclo. — The muscle-fibres of the Leech are peculiar; they consist 

 of an outer clear portion and a central granular part. In gold pre 

 parations the outer part stains the more deeply of the two portions 

 of the cell, and appears quite homogeneous, showing no trace of a 

 network. In osmic acid preparations the outer layer appears very 

 faintly fibrillated, but I could not identify any distinct fibrils differ- 

 entiated from the rest of the cell even under the y 1 ^ immersion 

 objective. 



Transverse sections of the muscle of the Leech show a radiating 

 appearance of dark and light bands in the outer portion of the cell. 

 This is, I believe, caused by the method of preparation, for in some 

 sections the outer portion of the cell is broken up into pieces 

 arranged in a radiating manner and corresponding to the light 

 portions betweeen the radiating dark lines in the better preserved 

 specimens. I find nothing corresponding to this appearance in 

 muscle prepared by the gold or osmic acid methods, which are the 

 methods generally recognised as maintaining the true histological 

 characters of cells intact. 



Wagener,* from transverse sections of dried specimens of Leech, 

 states that the muscle-cells consist of a central medullary substance 

 round the nucleus, and a cortical substance splitting into fibrils. This 

 is also described by Schwalbe in the fibres of Aulasiomum. 



Lumbricus terrestris. — Gold preparations of the muscle of the 

 Earthworm show large elongated cells which on close examination 

 show longitudinal lines ; these under the j\ immersion objective 

 present a dotted appearance (Fig. 3). At first sight it might 

 appear that we have here the network of striped muscle ; but this 

 is not the case. In the first place, there is no appearance of trans- 

 verse striation at all ; in the second place, the dots aro not arranged 

 transversely but are quite irregular ; lastly, so far as I could observe, 



* " Arehiv. f. Mik. Anat," 18UU. 



