MEMOIRS OF THE NATIOiSIAL ACADEMY OF SCIENCES. 331 



Pi.. XXXIII. From a microphotograpb of .a horizontal section through the brain of a young Limulus, involving 

 part of the oesophageal ring aud ganglia of the four anterior appc^ndages. (Section 32.) 



Pi.. XXXIV. The same, involving the six ganglia on one side of the cesophageal ring and the origin of the couue<-tive8 

 of the abdominal portion of the nervous 'cord. (Section 40. ) 



Pl. XXXV. The same (section 48) made lower down, showing the same ganglia, with their large ganglion cells, ;iuil 

 origin of the nerves to the six cephalothoracic appendages. 



Pl. XXXVI. Sagittal section through the brain of a young Limulus, showing the dark masses of chromatic ganglion 

 cells contrasting with the fibrous and punctured substance; con., connective passing to Hie 

 oesophageal ring. (Section 39.) All the miciophotographe were taken by Dr. W. M. Gray, U. S. A. 



ENB OF VOL. VI. 



