96 PHYSIOLOGICAL SERIES. 



C. 27. A section of the propodite and dactylopodite of the claw 

 of a Lobster, showing the attachment of the penniform 

 adductor from another point of view. 0. C. 61. 



ffunterian. 



C. 28. Portion of the claw of a Lobster (Homarus vulgaris}, 

 opened to show the points of attachment of the adductor 

 and abductor of the dactylopodite, and the great contrast 

 between them in size and power. 0. C. 61 D. 



C. 29. Leg of a Crab (Cancer pagurus) in \vhich the several 

 segments of the limb have been opened to show a pair of 

 involutions of the shell (apodemes), which extend upwards 

 from the upper margin of each segment (podomere) into 

 the cavity of that next above it. They are situated opposite 

 each other in a plane at right angles to that occupied by the 

 fulcra of the joint and serve as surfaces of attachment for 

 the muscles of the leg. Being part of the exoskeleton 

 they are cast with it in exuviation. In each joint the plane 

 of the fulcra is nearly at right angles to that of the next 

 joint above and below, so that by a suitable combination 

 of simple hinge-movements a great range of motion can 

 be attained. 0. C. 61 A. 



List, Morph. Jahrb., Bd. xxii. 1895, p. 392. 



C. 30. A section of the larva of a large North American Moth 

 (Bombyx regalis) showing two lateral series of muscles, 

 which extend along the dorsal and ventral aspects, through 

 the whole length of the body. These are intersected at 

 determinate distances, corresponding to the several segments 

 to which they are to give motion, and which have, also, 

 their own peculiar muscles. 0. C. 59. ffunterian. 



C. 31. A freshwater Mussel (Anodonta cygnea], of which part of 

 the right valve is removed, and the mantle dissected away, to 

 show a pair of muscles (retractor pedis posterior) going 

 obliquely from their origin upon the valves, in front of the 

 posterior adductor, to their insertion oh the foot. 0. C. 53. 



ffunterian. 



