All drawings made with the aid of a camera lueida, and all Sgures except 

 1 and is, by the use of Zeiss oculars and objectives. 



PLATE XII. 



Pig. 1.— Portion of a young decalcified internode of Crisia eburnea show- 

 showing the growing tissue {gr. lis.), the budding region {j„l 

 hi!.), and the alternate arrangement of the zooecia '.-.). 



Fig. 2.— Section from the tip of a male colony, .-lose to the edge, right or 

 left, showing the character of the cell layers, the small round 

 ectodermal cells (ee. els.), the larger mesodermal cells i mes. els.), 

 and a few cells of the germinal epithelium {ger. els. I. 600 



Fig. 3. — Section from the same series as the pre ling, showing practi- 

 cally the same cell layers at a point nearer the middle of the 

 tip where the ectodermal cells are thinning out and are becom- 

 ing elongated {ee. els.). 600 



Fig. 4. — Section from a male colony through tlte budding region. In the 

 angle toward the left edge of tlte branch, are a number of 

 germinal cells {ger. els.). Proximal to this is a young polypide 

 hud {pd. I'/l. .'). still lower down is an immature polypide 

 I r<l. bd. 1) possessing a stomach (sl.l, and an incipient testis 

 (tes.). 000 



Fig- 5.— Two spermatozoa from a ripe testis of C. eburnea. 2500 



Fig. 6. — Section of a zoceeium from a male colony showing a regenerat- 

 ing polypide {re. pd.), and below this a "brown body" (ft. ft.) 

 extending to the base of the zooecium. The brown body consists 

 of a homogeneous mass of yell,, wish brown degenerated cells, 

 Hie remains of the polypide {de. /»/.) and the testis {de. lis.). 

 600 



F'.?- ' '■ — Section through a zoceeium containing a normal testis. Distally, 

 the stomach (sf.) of the polypide is shown, while extending 

 into the base of the zoa?cium is the testis {tes.) in which tin- 

 cells are arranged in scattered groups of various sizes. Numer- 

 ous groups of four nuclei (tet.) are visible. < 600 



Fig. 7a.— Group of four nuclei {let.) in a mass of cytoplasm. 2500 



Fig. 8.— Section from the growing tip of a female colony showing the two 

 cell layers of the body wall, the outer or ectodermal layer {ee. 

 els.), consisting of small round cells, the inner or mesodermal 

 layer (mes.. els.) consisting of larger cells, part of which gives 

 rise to the germinal epithelium {ger. els.), part to the spindle- 

 shaped mesenchymatous tissus {mes. lis.). coo 



Figs. 9 and 10. — Serial sections from the same tip as the preceding. The 

 ova are accumulated in the corners {ger. els.). 600 



[149J 



