Davbntort. — Budding in Bryozoa. 



PLATE VI. 



ABBREVIATIONS. 



All figures from preparations of Paludicella Ehrenbergii. 



Fig. 52. Cross section of a branch through a polypide slightly older than tliat 

 shown in Figure 36. The section passes through tlie brain and whole 

 extent of the ring canal, together with its opening into the ccelom. 

 X 635. 



Next section below Figure 52 of same series ; showing the beginning of tlie 

 circumoesophageal nerve ring. X 635. 



Siiows connection of mesodermal cells of body wall, ms'drm, with those 

 of the outer layer of bud, ex. X 10.30. 



Origin of the secondary parietal muscle cells from mesoderm of body 

 wall. X 635. 



Histological conditions of the budding regions. The cells have large nu- 

 clei, the mesodermal cells are vacuolated and rapidly dividing ; the 

 cells of the bud are densely granular. Zeiss, ^-g oil immersion, Oc. 1. 

 X 1070. 



Normal vacuolated cell, full of food particles. X 1030. 



Longitudinal section of young lateral branch, showing highly reticulated 

 character of mesoderm, and nearly complete formation of communi- 

 cation plate. X 410. 



Reticulated cell, showing one of the pseudopodia-like processes which 

 frequently a])pear on them, projecting into the coelom. X 1030. 

 60-62. Three successive sections from a series across the tentacles of a pol- 

 ypide which has 15 tentacles, and is of about the stage of Figure 36. 

 The odd tentacle (*) is shorter than the others, and lies opposite the 

 rectum, rt. X 295. 

 Fig. 63. Cross section of branch through neck of polypide of about the age of Fig- 

 ure 36. Shows also the young pyramidal muscles. X 410. 



Fig. 



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Figs 



53. 



54. 



55. 



56 



59. 



