266 KINGSLEY. 



EXPLANATION OF PLATE XIL 



Fig. 70. Section posterior to that shown in i<ig. 69. The sternal arteries have 

 reached the nervous system and lie upon it. Beneath may be seen the anterior 

 extension of the ventral part of the neural artery. 



Fig. 71. More posterior, showing that the neural artery is paired above and 

 below and also showing connection of dorsal and ventral parts of neural artery. 



Fig. 72. Horizontal section, Stage L, through proventriculus, sternal arteries 

 and anterior end of mesenteron with ducts of the hepato-pancreas. 



Fig. 73. From the same series as 73, but passing through heart and showing 

 the bifurcation for sternal arteries, an. 



Fig. 74. Section from same series as Figs. 69-7 1 , ^>assing through fifth pair 

 of legs. 



Fig. 75. Through the abdomen, Stage L. 



Fig. 76. From the same series as Fig. 74, showing the connection of sternal 

 arteries with the heart and then splitting for the stomodaeum. 



Fig. 77. Reconstruction (wax) of the anterior end of the heart, sternal arteries 

 and neural artery, Stage K. At the left is shown the cavity for the ventral cord ; 

 the dark spots mark the places for the exit of nerves. 



Fig. 78. Long section through the abdomen, Stage G, showing the pit-like 

 invaginations behind appendages VII and VIII. 



Fig. 79. Operculum and anterior gill-bearing appendages, Stage I. (VII and 

 VIII should read VIII and IX respectively.) 



Fig. 80. First and second gill-bearing appendages. Stage L. 



Fig. 81. Longitudinal median section, Stage L, in which the connection 

 between the mesenteron and proctodaeum is not yet made. 



Fig. 82. Longitudinal section, Stage I. 



