MUSCULAR SYSTEM. 95 



generally represented tlie cut ends so as more clearly 

 to show tlie relative positions. 



If we commence the description of the abdominal 

 muscular system from the dorsal line, we shall first 

 meet with a straight wide muscle (PI. LIX, 1), 

 which lies on each side of the dorsal vessel, rising at 

 the front margin of the segment, and passing directly 

 backwards, through the segment and over the inter- 

 segmental membrane, is attached to the anterior 

 margin of the following segment. In several cases I 

 have found it continuous with the corresponding 

 muscle of the preceding segment. 



PI. LX. — 2. This muscle lies outside the preceding, 

 and, therefore, in PI. LIX is underneath, and hidden 

 by it. In some specimens it is straight, in others, as 

 in the one figured, it lies a little diagonally. 



PL LX. — 3 crosses under, or rather outside, No. 2. 

 Like the two preceding, it rises at the anterior margin 

 of the segment, and passes to that of the penultimate 

 one. 



PI. LIX. — 4. This muscle is one of those that 

 move the tail. It rises close to, but at the side of the 

 preceding, and passes diagonally backwards and down- 

 wards, curling round No. 5, which will be described 

 next, and eventually reaching its posterior attachment 

 at the dorsal side of the root of the tail. 



PL LIX. — 5. This muscle rises with a double head 

 immediately below the preceding, and, passing back- 

 wards, twists as it were round it, and is also attached 

 to the posterior margin of the following segment. 



PL LIX. — 6, 7. This is a transverse muscle. Its 

 upper end is double, and is attached not far from, but 

 rather in front of, the middle of the segment. It 

 passes straight down, and is inserted into the central 

 ventral piece. 



PL LIX. — 8 is inserted close to the anterior end of 

 No. 5, and passes diagonally backwards and down- 

 wards, outside No. 6, and is attached to the lower side 

 of the penultimate segment. 



