ZOOPHYTES. 253 



the Scotish seas, but, from having had very few, I can say little regarding 

 either. 



Dr Farre proposes here to constitute a genus Bowerbankia, including 

 two species, the repens and the densa. But in Dr Johnston's opinion, the 

 characters specified are scarcely sufficiently definite to justify the distinc- 

 tion between them. However it seems well founded. 



1. Bowerbankia repens. — Plate LIII. Figs. 1, 2, 3. — The general 

 character of this product, in as far as I have seen it, participates somewhat 

 of the nature of the Valkeria cuscuta, in the appearance of the stem and 

 distribution of the cells. 



A slender stalk rises slightly above the surface of old shells, or runs 

 irregularly over it. — Plate LIII. figs. 1, 2. From this there originate single 

 cells, and cells in pairs or in clusters, the whole irregular in position and 

 number. — Fig. 3. The cell is occupied by an ascidian hydra with ten ten- 

 tacula. Being apparently identified with the hydra of the following species, 

 farther commentary on it is unnecessary. 



This zoophyte is dingy white. 



2. Bowerbankia densa. — Plate LIII. Figs. 4-12. — The general aspect 

 of this species is somewhat diversified. It invests other marine substances 

 as a parasite, sometimes totally overspreading them, with rather a mossy 

 appearance. But I have not observed its form confined by any such de- 

 finite outline as will admit its reference to familiar objects, which may 

 be seen from two specimens represented of their natural dimensions. — 

 Plate LIII. figs. 4, 5. Accumulated hydras cover the surface invested. 



A magnified view of the upper portion of fig. 4, is given fig. 6 ; and 

 a transverse section of fig. 5, also magnified, in fig. 7. The whole seems 

 an accumulation of single cells. 



The body of the hydra protrudes very far. The cell is much altered ; 

 while the animal is in retreat, it is long, with an ovoidal summit, which 

 stretches upwards as the hydra rises to display ten active ciliated tenta- 

 cula. 



From the great protrusion of the body, and the transparence of the 



