726 PROCEEDINGS OF THE ACADEMY OF [NoV., 



Explanation of Plate XL. 



Nereis arenaceodentata. 



Fig. 1. — Dorsal view of anterior end. X 32. 



Figs. 2, 3 and 4. — Outlines without setae of the 1st, 5th and 30th parapodia 

 respectively, from cephalic side. X 56. 



Figs. 5 and 6. — Dorsal and ventral aspects respectively of protruded pro- 

 boscis, showing the arrangement of the paragnatha; from a dissec- 

 tion. X 32. 



Figs. 7 and 8. — Examples of the two kinds of setse, from somite XX. 

 X 1200. Many, of the stouter sort have the appendage much 

 shorter. 



Fig. 9. — Several of the paragnatha from the basal zone. X 360. 



Fig. 10. — The same from the median dorsal maxillary area. X 360. 



Loimia viridis. 



Fig. 11.— One of the stouter setse from somite X. X 250. These setse 

 are seldom so straight as represented in the drawing, which has been 

 somewhat diagrammatized from a camera sketch. 



Figs. 12, 13 and 14. — Three uncini from the dorsal, middle and ventral 

 regions respectively, of a torus of somite XXVI. X 360. These 

 show nearly the extremes of variation, figure 13 being the most usual 

 form, but slightly foreshortened. 



