PLATE VII. 



Fig. 36. — Nervous and muscular tracts of the dorsal surface of the hood. Aetinotrocha Species B. (Drawn from 



living specimen.) 

 Fig. 37. — Lateral view of anterior part of Aetinotrocha Species B., showing muscle tracts. (Drawn from living 



specimen. ) 

 Fig. 38. — Longitudinal section through the ganglion of an Aetinotrocha. r 'j Oil Immersion. 12 Zeiss Occulare. 



Camera. X 665. 

 Fig. 39. — Section through a ganglion cell in the collar nerve ring. Aetinotrocha Species B. T ' 2 Oil Immersion. X 81 



Oc. Camera. X 469. 

 Fig. 40. — Transverse section through the nerve tract of the ventral collar wall. Aetinotrocha Species B. fa Oi 



Immersion. 12 Zeiss Occulare. Camera. X 665. 

 Fig. 41. — Transverse section through the dorsal nerve tract where it passes down along the liases of the tentacles. 



Aetinotrocha Species B. ^ Oil 1 lersion. 12 Zeiss Occulare. Camera. X 665. 



Fig. 42. — Transverse section through the collar nerve ring. Aetinotrocha Species B. ,'_. Oil Immersion. 12 Zeiss 



Occulare. Camera. X 665. 

 Fig. 43. — Transverse section through the nerve tract around the edge of the hood. Aetinotrocha Species B. T \ Oil 



Immersion. 12 Zeiss Occulare. Camera. X 665. 

 Fig. 44. — Transverse section through the hood of Aetinotrocha Species B. Taken through the sensory papilla. Hood 



flattened out, J Oh. X 4 Oc. Camera. X 300. 

 Fig. 44a. — Continuation of series 44. Taken through the anterior part of the ganglion. J Ob. X4 Oc. Camera. 



X 300. 

 Fig. 4ib. — Continuation of series 44. Taken through the ganglion which is invaginated by the action of fixing 



agents. J, Ob. X 4 Oc. Camera. X 300. 

 128 



