EXPLANATION OF PLATE 10 



Fig. 1. Cross-section of the myelencephalon and myeleneephalic gland 

 of a Lepisosteus osseus, 250 mm. in length. Section taken slightly cepha- 

 lad of middle of gland, and cut farther cephalad on right than on left. 

 X 12. 



ABBREVIATIONS 



A region where tissue of gland extends into pia mater. 



4th vent. fourth ventricle. 



bl. ves. blood vessel. 



col. c. columnar epithelial cells. 



cann.-tiss. n. connective tissue network. 



d. gran. m. region dense with granular masses. 



endol. endolymph. 



fl. c. flattened epithelial cells. 



inf. pi. infolding of choroid plexus. 



med. medulla oblongata. 



nerv. nerve. 



pig. pigment cell. 



p.. m. pia mater. 



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