MUSCULAR TISSUE. 



181 



4. The muscular tissue of the crayfish alwaj^s has the 

 form of bands or fibres, of ver}^ various thickness, marked, 

 when viewed by transmitted light, by alternate darker and 



n. 



r 



i''-:'''^i^ ■IEJi'-^ LqI' 



721: 



TZl'. 







Fig. 52. — Astacns flnviat'ilis. — A, a single muscular fibre, transveri-e 

 diameter yyo^Ii of an incli ; B, a portion of the same more highly 

 magnified ; C, a smaller portion treated with alcohol and acetic 

 acid still more highly magnified ; D and E, the splitting up of a 

 part of a fibre, treated with picro-carmine, into fibrillse ; F, the 

 connection of a nervous with a muscular fibre which has been 

 treated with alcohol and acetic acid, a, darker, and h, clearer portions 

 of thefibrillae ; n, nuclei ; nv. nerve fibre ; s, sarcolemma ; f, tendon ; 

 1 — -5, successive dark granular st.ria3 answering to the granular 

 portions, a, of each fil:)rilla. 



