NO. 9 MUSCULATURE OF THE BLUE CRAB COCHRAN 4I 



ing forward and downward to its insertion with the other branches. 

 The muscle as a whole opposes the levator. 



126. Musculiis reductor meropoditis. — See /j/. 



isy. Mucidus abductor carpopoditis. — See 13S. 



128. Muscitliis adductor carpopoditis. — See ijp. 



I2p. Mitscidus productor propoditis. — See 140. 



I JO. AIusculus reductor propoditis. — See 141. 



iji. Miisculus abductor dactylopoditis. — See 142. 



IJ2. Musculus adductor dactylopoditis. — See 143. 



THE THIRD PEREIOPOD 



jjj a-g. Musculus proinotor a-g (figs. 12 A ; 13 A). — The anterior 

 branch (a) originates on the posterior surface of the endosternite 

 separating the fourth and fifth thoracic segments, going outward to 

 its insertion on the tendon attached to the anterior proximal rim of the 

 coxopodite. The second branch (b) originates on the same prolonga- 

 tion of the endopleurites on which 122 b of the preceding segment 

 takes origin. It travels ventrally beside 122 b, separated' from the 

 visceral masses only by a thin membrane, passing finally under the 

 anterior extension of the promotor of the fifth pereiopod until it joins 

 its tendon. Branch c originates mesally on the anterior upper edge 

 of the endosternite separating the sixth and seventh segments near to 

 its point of fusion with the endopleurite. The next two branches (d 

 and e), not very distinct from each other, arise on the lateral part of 

 the membrane encasing the anterior promotor of the fifth pereiopod. 

 Branch / arises on the anterior lateral surface of the intermediate endo- 

 pleurite, while branch g arises just behind it on the posterior surface 

 of the same 'endopleurite. All these go to the same insertion with 

 branch a. The muscle pulls the leg base forward. • 



1J4. Musculus rcmotor (fig. 12 H, I). — This unbranched muscle 

 arises on the pleural wall and on the endosternite separating the sixth 

 and seventh segments. Its insertion is on the proximal postaxial border 

 of the coxopodite. Its contraction causes the leg base to be drawn 

 backward. 



7J5 a-c. Muscidus levator a-c (fig. 12 H). — The most ventral 

 branch (a) begins on the anterior wall of the sixth and seventh thoracic 

 segments. The branch b, originating just above it on the same en- 

 dosternite, is perhaps not truly distinct from it. The third branch (c) 

 originates on the lateral part of the membrane covering the anterior 

 promotor of the fifth pereiopod. These three branches are all inserted 

 upon a heavy tendon attached to the proximal postaxial rim of the 

 basi-ischiopodite. The leg base is raised by their contraction. 



