ZooL— Vol. II.] ROBERTSON— ENTOPROCTA. 339 



annulated, the annulations consisting of wrinkles or folds in 

 the cuticle alone. Above the annulations the rigid portion 

 of the phalanx begins, wide at the base, and narrowing 

 somewhat suddenly into the slender, rigid portion. Each 

 dilatation, then, is capped by a truncated chitinous cone. 

 Beneath the thin cuticle of the dilatations the longitudinal 

 muscle fibers are seen, forming an inner sheath or mantle. 

 These are attached proximally to the stolon, and distally 

 to the base of the cone which covers the top of the dilata- 

 tion (fig. 13, in. dtl.). 



The rigid portion of each phalanx is covered externally 

 by a thin cuticle continuous over stolon and basal expan- 

 sion. Beneath is a thick chitinous layer, yellow or brown 

 in color, resembling that of the stolon. In it, numerous 

 pores occur irregularly disposed over the surface (fig. 13, 

 p.). In longitudinal section these appear as deep, wide 

 notches which are covered externally by the thin cuticle 

 (fig. 16, p.). Similar pores occur in the stalk of Ascopoda- 

 I'ia macropus, and Ehlers suggests that an opening to the out- 

 side may be found in them. There is no evidence for this 

 in G. ramosa. The interior of the phalanx is filled with a 

 mesenchymatous tissue continuous with that of the interior 

 of the muscular dilatation. Near the base of the rigid por- 

 tion of each phalanx a septum occurs. This is perforated 

 and allows a free passage from one part of the stalk to 

 another. The maximum number of phalanges in a stalk is 

 six so far as the writer has observed. Four or five is a 

 common number in the older parts of the colony. The 

 description of the first phalanx, however, answers in the 

 main, for all the others. As a stalk grows, the first calyx 

 is differentiated before the rigid portion of the first phalanx 

 has attained its full length. Before this time also, the first 

 annulations of a second expansion appear below the calyx, 

 so that by the time the calyx performs the function of 

 nutrition it may have been carried into or above the second 

 phalanx. Whether in this way the original calyx is carried 

 to the summit of a stalk containing the maximum number of 

 phalanges, or whether regeneration may occur before the 

 maximum height is reached, is perhaps doubtful. 



(2) December 17, igoo. 



