NEMERTEANS. 



117 



EXPLANATION OF PLATES. 



= internal circular muscle layer. 



= longitudinal muscle layer. 



= longitudinal muscle layer of cutis. 



= internal longitudinal muscle layer. 



= outer longitudinal muscle layer. 



= median dorsal nerve. 



= lateral nervous stem. 



= eyes. 



= oesophageal epithelium. 



= oesophagus. 



= oesophageal glandular layer. 



= oesophageal vascular lacunae. 



= proboscis. 



= pigment. 



= proboscis sheath. 



= rhynchocoelom. 



= vascular cephalic lacuna. 



= ventral ganglion. 



PLATE IV. 



Fig. 10. 



Fig. 11. 

 Fig. 12. 

 Fig. 13. 



Fig. U. 



Gerehratulus maculatus. Dorsal and ventral view of anterior end. x 2. 



Eupolia hemprichi. Dorsal and ventral view of anterior end. x 1. 



E. hemprichi. Anterior end of another specimen from dorsal surface, x 2. 



E. unistriata. Anterior end from dorsal surface, x \. 



Gerehratulus inaldivensis. Ventral view of anterior end. x 4. 



C. gardineri. Ventral view of anterior end. x 2. 



Drepanophorus roseus. Ventral view of anterior extremity. From specimen cleared in cedar 



oil. X 5. 

 Eupolia indica. Section through region of head furrow, shewing outline of brain, x 22. 

 Gerehratulus gardineri. Section through oesophageal region, shewing relative thickness of 

 muscle layers and position of excretory duct, x 15. 

 Drepanophorus cerinus. Section through brain region immediately after the separation of 



the dorsal and ventral ganglia, x 45. 

 Z>. cerinus. Section just anterior to the opening of the cerebral organ, x 45. 

 Eupolia indica. Section through cerebral organ and hinder part of dorsal ganglion, x 45. 

 E. indica. Grooved epithelium of circular head furrow as seen when more highly magnified 



than in Fig. 8. 

 E. indica. Section through portion of oesophagus in excretory region, shewing a cord of 

 cells from an excretory tubule* piercing the oesophageal glandular layer and reaching to 

 the inner surface of the alimentary canal, x 80. 



* The asterisk marks the level where the dorsal vessel emerges from the proboscis sheath. 



