Note on the Legs of Trjlobitks. 65 



EXPLANATION OF PLATE I. 



Fig. 1. Transverse section of the head of Calymene senaria, passing- directly do wn 

 ward, so as to cut the hypostoma just within its posterior margin. 

 a Dorsal shell. 

 b Visceral cavity. 

 c Hypostoma. 



d Terminal joints of manducatory leg-. 

 1 Coxa of posterior manducatory leg. 

 2, 3, 4 Manducatory appendages or legs. 



Fig. 2. Another transverse section of the head of Calymene senaria. 



e Membraneous crust connecting visceral cavity and doublure. 

 o Base of fourth pair of manducatory leg's. 



Fig. 3. Section of the leg- or axial appendage of Ceraurus plurexanthemus. 

 1, 2, 3, 4. Joints of leg-. 

 a Terminal claw. 

 b Edge of section. 



Fig. 4. Supposed swimming foot or terminal joint of posterior manducatory leg - . 

 a Terminal joint. 

 b Three small joints and spine. 

 c Restored outline of terminal joint. 



Fig. 5. Transverse section of the thorax of Calymene senaria partially restored. 

 a Dorsal shell. 

 b Visceral cavity. 

 c Legs restored. 

 d Epipodite. 



e Spiral gills, as seen in detached condition in other sections. 

 / Actual section of spiral gill. 

 g Same restored. 



Figs. 6 and 7. Legs of six joints, each e 1 ^rged to two diameters. From Dr. C. A. 



Miller, of Cincinnati, 0. 



Figs. 1-5 (with the exception of portions of the latter) are copies of the original sec- 

 tions. 



