Davenport. — Budding in Brjozoa. 



PLATE V. 



ABBREVIATIONS. 



an. Anus. kmp'drm. Kamptoderm. 



cev. pyd. Neck of the polypide. loph. Lophophore. 



dr. set. CoUare setosum. ms'drm. Mesoderm. 



eta. Normal cuticula of adult mu. par. Parietal muscles. 



body wall. mu. pyr. Pyramidal muscles. 



eta.' Cuticula secreted by the tip of. atr. Atrial opening. 



of branch. rt. Rectum. ^ 



ec'drm. Ectoderm. spht. Sphincter. 



Fig. 42. 

 Figs. 43 



Fig. 45. 



Fig. 46. 



Figs. 47 



Fig. 50. 

 Fig. 51. 



All figures from preparations of Paludicella Ehrenbergii. 



Cross section of branch of age of Figure 37, Plate IV., to show origin of 

 primary parietal muscles. X 410. 

 and 44. Successive sections through a polypide slightly older than that 

 of Figure 25, cut perpendicularly to the long axis of the branch. Dur- 

 ing this period the lophophore becomes more nearly circular, and its 

 aboral ends meet oralwards of the rectum, rt. Figure 44 is nearer tlie 

 tip of the branch. X 410. 



Axial section of neck and atrial opening of polypide just sufficiently devel- 

 oped to be capable of extrusion. Shows the collare setosum in place. 

 X410. 



Section of communication plate cut across the branch. Two sections 

 (10 ix) above Figure 51. X 635. 



Three stages in the development of tlie communication plates. Lon- 

 • gitudinal sections of the branch. In Figure 47, the polypide has 

 reached the stage of Figure 22 ; in Figure 48, the stage of Figure 23 ; 

 and in Figure 49, the stage of Figure 24. X 635. 



Longitudinal section through neck of young polypide, showing the sink- 

 ing of the neck below the general surface of the body, and the method 

 of forming tlie inner cuticula of neck. X 390. 



Cross section of branch through communication plate. The left side 

 of the section includes the cuticula and the underlying flat ectoderjual 

 layer. The right side cuts a little lower into the mesodermal cells. 

 X 635. 



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