182 MR. LUBBOCK ON THE CUTANEOUS MUSCLES 



No. 40 is longer than in the second thoracic. In one specimen it was single behind, 

 and inserted between 51 and 66. 



Nos. 46 and 49 are both quite single, and much larger than in the segments following. 



No. 50 is wanting. 



No. 51 rises at the posterior end of 40, and passes downward to be inserted under 17. 

 This muscle may perhaps be rather the representative of 54. 



No. 52 rises close to the lower end of 49 and passes downward and backward. 



Nos. 54 and 55 are absent. 



Nos. 59 and 60. There are three or four separate fascicles which apparently represent 

 these two muscles. They He in front of 9, and are parallel to the du-ection of the 

 segment. 



No. 61 is almost or sometimes completely double. It rises at the fore end of 82, and 

 the two branches diverge slightly, both being inserted under 59 and 60. 



No. 62 consists of three or four smaU oblique fascicles which rise along the front of the 

 segment under the thi'ee preceding muscles and pass backward and upward. 



Nos. 63 and 64 are absent. 



No. 65 rises close to the lower end of 49 and passes upward and forward. It is very 

 doubtful whether this muscle is homologous with that marked 65 in the other segments. 



No. 66 is much less conspicuous than in the other thoracic segments. 



No. 67 rises under the upper end of 49 and passes to the hinder end of 41. 



Nos. 68 and 69 rise in front as usual, but pass back parallel with one another to the 

 upper end of 51. 



Nos. 70 and 71 are parallel with 65. 



Nos. 72, 73, 74 and 75 are absent. 



No. 79 lies under 77 as usual, and in this segment is hidden by it. 



No 80 rises close to the anterior end of 19 and passes downward, at the same time 

 with a slight inclination backward, to the middle line of the segment, close to 56. At 

 its lower end it is double. 



No. 81 resembles 80, but is smaller ; it lies also rather in front, and passes on the outer 

 instead of on the inner side of 19, 20 and 26. 



No. 82 has been already described. 



No. 83 is devoted to the spiracle, from which it passes forward and upward to the 

 upper end of 46. 



Nos. 84 and 85 rise at the lower end and a little in front of 49, and diverging from one 

 another, pass backward and downward ; 85 is inserted near the posterior end of 57 and 

 58, and 84 on the ventral side of them, near their fore end. 



Posterior Abdominal Segments. — Having thus described the thoracic segments, I now 

 return to the abdomen. The fourth, fifth and sixth abdominal segments do not mate- 

 rially differ from the third. The muscles, however, become narrower and thus occupy 

 less space. 



No. 26 is double behind, thus indicating the more complete separation which is to 

 take place in the following segment. 



No. 28 is absent. In the fifth and sixth segments there is also a muscle which rises 



