No. 441.] CORYMORPHA PENDULA AG. 



in the course of development, to extend up into the papilla for a 

 short distance as seen in Fig. 4 c. As the layer of mesoglcea 

 is thus interrupted, the peripheral entodermal cells extend up 

 into the papilla, t 1 ^ a central axis of entoderm. L. Agassiz 

 ('62) states that these papilla? are hollow and are permeated by 

 prolongations of the chymiferous tubes of the stem. Allman 

 ('71, p. 209) in a description of C. nutans, modifies this state- 

 ment somewhat and says, " They apparently communicate with 



the canal over which they lie." From a study of a number of 

 sections I have been unable to verify this statement of Agassiz. 

 Not only do the papillae very often lie in regions other than over 

 the chymiferous canals — I have frequently found them growing 

 out of an area of the stem between two canals — but all of the 

 sections show the papillae to be solid, composed of an ectoderm 

 and a central core of entoderm. They are not hollow, but main- 

 tain this solid character even after they have grown into com- 

 paratively long filaments. (Fig. 5.) 



As these papilhx continue to grow and elongate, they finally 



