44 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



strands go more deeply than others. The branches of this muscle go 

 to a mutual insertion on a heavy tendon coming from the upper 

 proximal border of the coxopodite. Their contraction causes the leg 

 base to be elevated. 



I4y a-d. Musculus depressor a-d (fig. 12 J, K, L). — ^The first 

 branch (a) originates partly on the posterior wall of the endosternite 

 separating the sixth and seventh segments, partly on the sternal wall 

 of the seventh segment, and partly on the anterior surface of the 

 endosternite between the seventh and eighth segments of the thorax. 

 The second branch (&) lies behind the posterior part of the first 

 branch, spreading in a fan shape over the endosternite between the 

 seventh and eighth segments of the thorax. It might be considered 

 as being more than a single branch, as it is not very compact at 

 its source. The third and fourth branches {c and d) begin on the 

 anterior and posterior walls respectively of the coxopodite. All 

 branches of this muscle go to the same heavy tendon fastened to the 

 proximal ventral rim of the basi-ischiopodite. The muscle opposes the 

 levator efifectively. 



148. Muscidus rcductor rneropoditis. — See ij/. 



14Q. Musculus abductor carpopoditis.- — See 1^8. 



ijo. Muscidus adductor carpopoditis. — See ijp. 



757. Musculus productor propoditis. — See 140. * 



ij2. Musculus reductor propoditis. — See 141. 



75J. Musculus abductor dactylopoditis. — See 142. 



Ij4. Musculus adductor dactylopoditis. — See 14^. 



THE FIFTH PEREIOFOD 



755 a-c. Musculus promotor a-c (fig. 12 M). — The longest and 

 heaviest branch (a) originates anteriorly on the median plate and 

 passes posteriorly and laterally to its insertion on the tendon on the 

 membrane at the anteroventral border of the coxopodite. The next 

 branch (&) is very prominent, originating on the posterior surface of 

 the membrane which projects diagonally forward through the pre- 

 ceding segments and on the anterior surface of which some of the 

 branches of muscles of the second, third, and fourth pereiopods were 

 attached. The third branch (c) is the smallest. It arises on the poste- 

 rior surface of the endosternite between the seventh and eighth seg- 

 ments, being inserted above branch b on its tendon. The muscle im- 

 parts a forward motion to the leg. 



756 a and b. Musculus rcmotor a-b (fig. 12 M, O). — In this pereio- 

 pod the remotor differs from the corresponding muscle in the other 



