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MONTGOMERY. 



EXPLANATION OF PLATE XXVI. 



Fig. 40. Cerebratulus lacteus : segment of a cross section through the lateral 

 side of the fibrous core of the lateral nerve chord, from about the middle body 

 region. Sublimate, Ehrl. haematoxylin + eosin. 



Fig. 41. Tetrastemma vermiculu77i : portion of a horizontal, longitudinal 

 section of a lateral nerve chord (only the outlines drawn), shovring a supposed 

 nerve tube {N. T. ?) stained with methylene blue. Sublimate, aq. sol. of methylene 

 blue 10 minutes, aq. sol. of brasilin 40 minutes. 



Fig. 42 a-e. Cerebratubcs lacteus : portions of longitudinal sections of neuro- 

 chord tubules, from the fibrous core of the lateral nerve chord, behind the middle 

 body region. Sublimate, Del. haematoxylin + eosin. 



Fig. 43. Lineus gesserensis : portion of a cross section of the posterior 

 ventral portion of the brain, showing the second ventral commissure. Obj. C, 

 oc. 2. Hermann's fluid. 



