5 I o JOHNSON. [Vol. \' 1 1 1 . 



by a comparison of Figs. 26-28, 33, 35-37, r.s. The ramifying 

 zone of the distal zooid is, on the contrary, formed anew. As 

 soon as the constriction at the anterior end of the new zone 

 has cut down an appreciable distance along the side of the 

 animal, a very distinct derangement of stripes appears imme- 

 diately above it, and lengthens with that portion of the distal 

 zo5id (Figs. 35, 36, r.z.'^). The newly formed ramifying zone 

 is different from that of older individuals, inasmuch as it is not 

 strictly a branching, but an inosculation of stripes, meeting at 

 an angle of about 45° when the animal is extended. This 

 condition of the ramifying zone persists for some hours after 

 fission. 



How is the new ramifying zone produced .'' Schuberg explains 

 it as a result of a rupture of the pellicula in the fission-line, 

 and apparent weight is lent to this view from the fact that 

 lesions almost invariably lead to disorganization of the stripes 

 as a result of the closure of the wound. A rupture of the 

 pellicula, however, is not necessar)'^ to account for the ramifying 

 zone. An inspection of Figs. 32 and 33 will show that the 

 constriction-cleft at the aboral extremity of the new zone is the 

 apex of the fission-line, which on both dorsal and ventral sides 

 cuts the stripes obliquely. As the constriction becomes deeper, 

 the ends of the stripes immediately posterior to the cleft in 

 Fig. 33 must become pinched together as they come down to 

 the constriction-line upon both dorsal and ventral sides of the 

 anterior zooid. This process continues until the end of fission. 

 The result is a seam in the side of the distal zooid, where the 

 stripes meet and inosculate at their tips as above described. 



After the daughter-stentors have assumed nearly their 

 definitive shape, separation is effected by rupture of the 

 connecting thread at the point where it joins the proximal 

 individual. This is accomplished partly by the pulling and 

 torsion of the distal individual, and in part by the sudden 

 in-cutting of the now much reduced line of constriction (Figs. 

 36, 37). The latter process brings about a speedy separation (in 

 most cases) of the twin zooids, and also leaves an area of naked 

 cytoplasm for the foot (Fig. 37, ps.^). Sometimes, especially 

 if the animal is well-fed and vigorous, the incision separates the 



