178 Macteay Memortat Vouume. 
PLATE XIX. 
Fig. 10.—Sagittal section of the body, showing the muscles of the abdomen, antenna, mandible, &e. 
Fig. 11.—The same, with portions of the enveloping muscles removed. 
PLATE xx. 
Fig. 12.—Intrinsic muscles of the fourth leg. 
Figs. 13-17.—Extrinsic muscles of the same, posterior aspect: fig. 13, after removal of the fifth leg ; fig. 14, 
after removal of the endosternite and arthrophragm ; fig. 15, after removal of the posterior 
wall of the coxopodite ; fig. 16, after removal of the abductor and depressor; fig. 17, after 
removal of the levator. 
Fig. 18.—Muscles of a swimmeret (male). 
Fig. 19.—Muscles of the first maxilla. 
Fig. 20.—Muscles of the second maxilla: the adductor and long abductor are removed on the right side. 
Fig. 21.—Muscles of the right antennule, from the outer side. 
Fig. 22.—The same after removal of the abductor and external long antennulary muscles. 
Fig. 23.—The articulation of the left antennule as exposed by the removal of the muscles from the onter 
side. 
Fig. 24.--The anterior region of the head, seen from within, showing the extrinsic muscles of the 
antennule, &e. 
Fig. 25.—A similar dissection (twice natural size), showing the ophthalmic muscles. 
PLATE XXI. 
Fig. 26.—Diagram of the abdominal muscles in the form of a sagittal section, 
Fig. 27.—Diagram of the ventral muscles of the abdomen, dorsal aspect. 
