CoE.— Nemerteans. 



PLATE 18. 



Figs. Ill to 115, Tetrastemma nigrifrons Coe. 

 Figs. 116 to 118, Amphiporus biniaculatus Coe. 



Fig. 111. Tetrastemma nigrifrons. Dorsal surface of head and anterior por- 

 tion of body, showing tlie two pairs of cephalic grooves, of which 

 the posterior pair forms a distinct collar. The black cephalic 

 marking and the dark color of body back of head are represented 

 by dark shading. X 20. 



Fig. 112. T. nigrifrons. Ventral side of head, showing position of cephalic 

 grooves and extent of dark coloring on body. X 20. 



Fig. 113. T. nigrifrons. Dorsal side of head of pale variety, showing position 

 of cephalic grooves, ocelli and cephalic marking. X 35. 



Fig. 114. T. nigrifrons. Central stylet and basis, showing dark posterior 

 portion of latter. X 200. 



Fig. 115. T. nigrifrons. Stylet apparatus. Basis with dark posterior portion. 

 X 50. 



Fig. 116. Amphiporus bimaculatus. Ventral side of head. The extent of the 

 fluted cephalic grooves is shown on ventral surface, and is rep- 

 resented in outline on dorsal surface. X 12. 



Fig. 117. A. bimaculatus. Dorsal side of head and anterior portion of body, 

 showing extent of fluted cephalic grooves, position of cephalic 

 markings, and arrangement of ocelli. A pair of inconspicuous 

 oblique grooves occurs back of head. X 12. 



Fig. 118. A. bimaculatus. Central stylet and basis. X 240. 



(Figs. Ill, 112, 116, 117 after drawings by J. F. Abbott. Others by W. R. 

 Coe.) 



