90 MUSCULAR SYSTEM. 



before the publication of my papers in the ' Linnean 

 Transactions.'^ 



With patience and spirits of wine, however, I have 

 been able to make out the principal muscles pretty 

 clearly. 



I will describe those of Smy^ithurus and of Tomocerus, 

 as representing respectively the globular and linear 

 species. The largest muscles are those connected with 

 the saltatorial apparatus. In SmyntJmrus these mus- 

 cles (Pis. LVII, LVIII) are nine in number on each 

 side of the body. The stoutest of all (Pis. LYII, 

 LVIX) rises on the ventral side of the body, close to 

 the middle line, and immediately in front of the rever- 

 sible base of the saltatory apparatus. It passes up- 

 wards, expanding gradually, and is inserted sometimes 

 by one, (PI. LVIII, h) sometimes by two heads (PI. 

 LVII, h) on the side-wall of the body. 

 ■ The second muscle, which is much smaller (c d), rises 

 behind the first, and somewhat further from the middle 

 line, being separated from the corresponding one on 

 the other side by the central thickened part of the 

 reversible base of the spring. It passes straight 

 upwards, without altering in diameter, and is attached 

 to the skin at d, behind, but on the same line as the 

 preceding muscle. 



The third muscle (PI. LVIII, e f) rises close to the 

 preceding, but a little outside it, and, passing upwards 

 and forwards, is attached close to the posterior branch 

 of the first muscle, by which, therefore, in PI. LVII 

 it is necessarily concealed. 



The fourth (A) lies parallel to, and rather behind 

 the second ; it is, however, rather shorter, and conse- 

 quently does not reach so far up towards the back. 



The fifth {i j) rises close behind the last three. It 

 is shorter and broader, and passes straight backwards 

 to the posterior wall of the body, where it is inserted 

 between the spring and the small terminal abdominal 

 segment. 



» ' Tran. Linn. Soc./ 1862 and 1868. 



