NO. 9 MUSCULATURE OF THK BLUE CRAB COCHRAN 39 



mediate endopleurite. A third branch (c) begins behind this cndo- 

 pleurite on the lateral surface of the menilirane holding the anterior 

 promotor branches of the fifth pereiopod which extends forward 

 through the thorax and gives attachment to many muscles, and runs 

 into branch h at their mutual insertion. These muscle parts act to- 

 gether in raising the leg base. 



114 a-g. MhschIhs depressor o-g (figs. 12 A, B, C; 13 R). — The 

 first branch ((7) originates mesally on the sternum and passes out- 

 ward to its insertion on the tendon attached to the membrane on the 

 preaxial proximal border of the basi-ischiopodite. The second l)ranch 

 (7;) is very indistinctly separated from the first, originating in several 

 sections along the anterior edge of the endosternite separating the 

 fourth and fifth thoracic segments. A third branch (c) which appears 

 to be quite distinct, originates on the extreme lateral part of the same 

 endosternite beneath 7/5 a, and comes forward to its insertion on the 

 membrane of the lower proximal border of the basi-ischiopodite. The 

 fourth branch {d) begins behind the intermediate endojjleurite on the 

 under surface of the pleural wall separating the gill chamljer from the 

 fifth thoracic segment. The remaining branches (c, /, and g) originate 

 at difl"erent points in the posterior part of the coxopodite. These three 

 last-named branches are not compact, and it is possible to subdivide 

 them still further than this. The distinctness of these minor branches 

 varies considerably according to the state of preservation of the tissues, 

 and consequently appears to be much less evident in some individuals 

 than in others. They are inserted side by side along the lower and post- 

 axial proximal margins of the basi-ischiopodite. The depressor muscle 

 as a whole gives a very strong downward movement to the leg base. 



j/5. Musculns reductor ineropoditis. — See 157. 



116. Musculus abductor car popoditis. — See 1^8. 



11/. Musculus adductor carpopoditis.— -See /jp. 



118. Musculus productor propoditis. — See 140. 



up. Musculus reductor propoditis. — See 141. 



120. Musculus abductor dactylopoditis. — See 142. 



121. Musculus adductor dactylopoditis. — See 14^. 



THE SECOND PEREIOPOD 



122 a-d. Musculus promotor a-d (fig. 12 D). — The most anterior 

 part (a) arises on the posterior surface of the endosternite separating 

 the fourth and fifth thoracic segments, passing downward and out- 

 ward to its insertion on a heavy tendon coming from the proximal 

 preaxial rim of the coxopodite. The long and slender branch (b) 



