PLATE V. 



Pig. 26 Horizontal section through a larva somew hat older than that of fig. 24, but younger than that of fig. 25. 

 Shows tli.- separation of the eel Is of the nephridial pit into two wings, ,'j oil Immersion. X 8 Oc. 

 Camera. 7iM. 

 Fig. 27. Horizontal section of posterior end showing slightly older stage in the development of the nephridia than 



that of fig. 26. rj Oil Immersion. 8 0c. Camera. X 704. 

 Fig. 28. Horizontal section through a larva with beginnings of two tentacles. Shows nephridia. ,'. Oil Immersion. 



X8 0c. Camera. X 704. 

 FlG. 29a. Transverse section through posterior end of a larva with two pairs of tentacles. ,' : Oil Immersion. X 8 



Oc. Camera. X 704. 

 Fig. 296. Continuation of series 29a. Taken through the region of the rectum. T V Oil Immersion. > 8 0c. 



Camera. 704. 

 Fig. 29c. Continuation of series 29. Taken through the middle of the larva. r ' 3 oil Immersion. X8 < >c. 



Camera. X 704. 

 Fig. 29e. Continuation of series 29r<. Taken through the body proper and the lower part of the hood. ,'. Oil 



Immersion. X 8 Oc. Camera. -.704. 

 Fig. 29d. Continuation of series 29a. Taken through body and hood near the region of the mouth. ,'_. Oil 



Immersion. X 8 Oc. Camera. X 704. 

 Fio. 30. Almost a sagittal section through a larva with two tentacles. T V OH Immersion. X 8 Oc. Camera. X 704. 

 Fig. 31. Larva with three pairs of tentacles. Outline drawing from life. J Ob. X 4 Oc. Camera. X 225. 

 Fig. 32. Larva with five pairs of tentacles. Outline drawing from life. 5 < >b. X 8 Oc. Camera. X 202. 

 Fig. 33. Larva with six pairs of tentacles. Outline drawing from life. f Ob. X 8 Oc. Camera. X 202. 

 124 



