338 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



important difference, since in a colony of G. ramosa indi- 

 viduals resembling G. nodosa may be found. But the 

 branching is peculiar to this form and warrants the forma- 

 tion of a new species. 



A . Structure. 



1. The Stolon. — This is stout and thicker than the 

 ascending stalks. It has a yellow color in the younger parts 

 of the colony but becomes brown with age. It is covered by 

 a thin, transparent cuticle continuous over stalk and calyx. 

 Beneath the cuticle is a thick chitinous layer to which the 

 color and rigidity of the stolon are due. It is divided at 

 intervals by perforated septa into segments of varying 

 length. A segment which does not bear a polypide is inter- 

 calated between two which do. Sometimes the polypide- 

 bearing segments are crowded together, in which case the 

 intercalated segments are very short, and the septa at their 

 extremities are placed almost close together. The stolon 

 produces branches at right angles to it, or nearly so. These 

 grow from below the basal dilatation of an ascending stalk, 

 and may appear on one side only, or opposite, on both 

 sides. In no case has a branch been observed to grow from 

 a non-polypide-bearing segment of the stolon. 



2. The Stalk. — The stalk begins as a muscular dilata- 

 tion resting upon the stolon. Above this it grows slender, 

 but stiff and rigid. The occurrence of several of these dila- 

 tations divides the stalk into definite sections to which, 

 following Ehlers, the name phalanx will be applied — a 

 phalanx being considered to consist of a dilatation and the 

 rigid portion arising therefrom (fig. 13, pha.). The distal 

 phalanx, then, may frequently consist of a dilatation and 

 a calyx, depending upon the stage of growth to which the 

 stalk has attained. Since the musculature of the stalk is 

 confined to these bulbous dilatations at the base of each 

 phalanx, the stalk is of the type merosarcine. The basal 

 or proximal dilatation arises from the stolon with a rather 

 broad base, widening out somewhat into a barrel-shaped 

 structure. It is covered by a thin cuticle which is distinctly 



