186 ZOOPHYTES. 



more days a slender stem, with a bulbous summit, had issued from the 

 roots. The stem of some others rose in extreme slenderness ; but none 

 produced hydrse, probably from some accidental cause. 



Plate XXXV. 



Fig. 1. Group of the Sertularia {Plwmularia) pinnata on a shell. 



2. Summit of a specimen. 



3. Twig with cells. 



4. Hydra. 



5. Hydra containing some residuum. 



6. Vesicles, as seated on the stem. 



7. ProUfic vesicles. 



8. Yellow planulse from the vesicles. 



9. Planulee from the vesicles ; one monstrous, a, more enlarged. 

 10. Nascent specimen from a planula. 



All the figures of this plate, except fig. 1, are enlarged. 



§ 10. Sektularia (Plumulaeia ?) Fascis.— Plate XXXVI.— As this 

 product participates of various characters whereon the later invented genera 

 are established, its real position is somewhat doubtful, nor have I had a 

 sufficient number of specimens in their various states to fix it. 



The Sertularia fascis rises four inches or more in height, by a straight, 

 erect, and rather inflexible stem, under half a line in diameter at the root. 

 Alternate boughs, bearing very few branches, generally none, are meagrely 

 disposed around the circumference. A single row of low denticles, for the 

 most part on one side only, borders the upper surface of the parts, scarcely 

 projecting above its level, and many of the extremities terminate in a den- 

 ticle also. On some subordinate parts, a border of denticles appears on 

 each side, but rarely. The denticles are usually separated by articula- 

 tions. 



The lower portion of the stem is composed of aggregated tubuli like 

 a faggot, each most probably occupied by its peculiar pith, which substance 

 is more distinct above, where exposed by the transparence of the single 

 tubular parts. The waving form of the pith indicates an invisible side or 



