98 THE MUSCULAR SYSTEM. 



tions of Nos. 5 and 8, and passes forwards with a slight 

 inclination downwards. It lies on the outer side of 

 Nos. 6 and 7, and is attached, in the ordinary way, to 

 the anterior margin of the segment. 



PI. LX. — No. 11 lies oiitside the preceding. Some of 

 the upper fibres did not, in the specimens I examined, 

 reach so far as the margin of the segment. 



Pis. LIX and LXI.— No. 12. This muscle, which 

 belongs partly to this segment and partly to the ante- 

 penultimate, has already been described. 



Pis. LX and LXI. — No. 13. This powerful muscle 

 rises by a double head. One portion lies under No. 12, 

 which is cut away at that part in PI. IjX in order to 

 show No. 13 ; the other and larger portion is attached 

 by a broad base to the gently curved arch, which here 

 runs along the segment. Both branches soon unite, 

 and pass straight forward completely through this 

 segment, to the anterior margin of the second. 



Pis. LX and LXI. — No. 14. This and the following 

 are short, but powerful, transverse muscles. The 

 present one rises under No. 13, but extends somewhat in 

 front of it, and passes downwards and a little forwards 

 to the ventral part of the segment. 



Pis. LIX, LX, and LXL— No. 15. This muscle is 

 attached, like the preceding, which it crosses, to the 

 gently curved arch already mentioned. It is attached 

 above, in front, and below behind the preceding- 

 muscle, outside of which it runs. These two muscles 

 are fan-shaped ; and though their ventral ends are of 

 moderate size, their dorsal extremities are so wide that 

 between them they extend over the whole length of 

 the segment. 



Pis. LIX and LXI. — No. 16 also rises by two heads, 

 and lies outside No. 15 ; it passes forward, straight 

 into the thorax, and is attached close behind the head. 



Second Ahdominal Segment. 

 In this segment the dorsal muscles are much weaker 



