• PLATE XI. 



-Transverse oblique section through Actinotrocha Species A. Taken through region of origin of blood 



corpuscles. 14 tentacles, j'j Oil Immersion. X 4 Oc. Camera. X 293. 

 -Transverse section through ventral collar wall. Same specimen as that of fig. 53. Showing origin of blood 



corpuscles. T 'j Oil Immersion. 12 Zeiss Comp. Occulare. Camera. X 935. 

 -Actinotrocha Species B with ventral pouch evaginated. f Ob. X 8 Oc. Camera. X 45. 

 -Actinotrocha Species A. Immediately before metamorphosis. § Ob. X 4 Oc. Camera. X 56. 

 — Actinotrocha Species A. Shortly after the beginning of metamorphosis. § Ob. X 4 Oc. Camera. X 56. 

 —Metamorphosed A ctinotrocha Species A. § Ob. X4 0c. Camera. X56. 

 -Young specimen of Phoronis architecta (?) with 30 tentacles. § Ob. X 4 Oc. Camera. X 28. 

 -Metamorphosed Actinotrocha Species A. Transverse section through the region of the transverse septum, 

 i Ob. X 8 Oc. Camera. X 240. 

 Fig. 60. — Completely metamorphosed Actinotrocha Species A. Transverse section in region of branching of efferent 



vessel. I Ob. X 8 Oc. Camera. X 240. 

 Fio. 61. — Adult Phoronis architecta removed from tube. X8. ' 

 136 



