388 Prof. J. Reid on the Anatomy and 



to the tentacula and intestine, but are seen passing downwards 

 from the upper part of the cell along the sides of the tentacula 

 to reach the gullet, and probably also the upper edge of the sto- 

 mach. The flexible tube or operculum is retracted by two mus- 

 cular bundles, one on each side, arising from the inner sides of 

 and a little below the aperture of the polype-cell, and are in- 

 serted into the inner surface of the flexible tube. The young 

 polype-cells, formed. at the upper end of the branches, grow 

 from the posterior surface of the polype-cells last formed a little 

 below their upper margin. Their first appearance is that of a 

 rough transverse line occupying the inner portion of that surface. 

 Several specimens presented the bodies frequently termed oper- 

 cula, but which we shall call ovary -capsules, placed as usual at 

 the upper end of the polype-cells, and were here somewhat nearer 

 their inner than their outer margins. The contents of these we 

 shall describe in a subsequent part of this communication. 



Cellularia scruposa. This polype is found, as I have already men- 

 tioned, in the same locality with C. reptans^ and it is also thrown 

 ashore from deep water, sometimes in considerable quantities and 

 of more luxuriant growth, chiefly adhering to Flustra foliacea and 

 F. truncata. A perpendicular hollow process springs from the 

 upper and outer edge of the cell immediately above the already 

 well-known tooth-like process, and adheres to the lower part of 

 the outer edge of the cell immediately above (fig. 6 a, and fig. 7 b). 

 The aperture of this process is pretty deeply notched before and 

 behind, and its interior is filled with a contractile fibrous sub- 

 stance which moves a curved hair-like prolongation (fig. 7 b) 

 about the length of the cell, which sweeps at intervals over both 

 the anterior and posterior surfaces of the polypidom within 

 its reach. It rises up slowly over the anterior surface, makes a 

 sudden jerk over the outer edge of the polypidom, and proceeds 

 slowly downwards over the posterior surface as far as the notch 

 in the aperture permits, and after remaining at rest for a longer 

 or shorter time, it returns along the same course to the position 

 from which it started. In this movement it performs a slight 

 rotatory motion, so that its concavity is always directed towards 

 the surface of the polypidom. This hair-like prolongation, in this 

 as in Cellularia reptans, tapers gradually towards its free extre- 

 mity, and is not rounded but flattened. In the C. reptans I 

 never observed this hair-like prolongation cross the anterior sur- 

 face of the polypidom, except when placed at the angle of the 

 bifurcation of a branch. The use of these hair-like prolon- 

 gations may probably be to keep the surface of the polypidom 

 clear of substances which would otherwise adhere to it. Their 

 motions are executed with more force than we should at first 

 suspect. I have seen one of them in its course encounter the 



