60 SHELL GALLEKY. 



Case A. (Fig. 8), one of the treasures of the " Challenger " Expedition, was 



Upright dredged from 1525 fathoms off Cape St. Vincent. The stem, which' 



^''''*' tapers gradually upwards, rises from a tuft of root fibres. The^ cup 



is formW of slender branches supported at the base by a delicate 



membrane. The branches are composed of biserial rows of cells 



(Fig. 9) opening towards the interior of the cup. The avicularia are 



Fig. 9. 



KinetosMas cyatlius. A branch magnified. 

 a, an avicularium. (After Busk.) 



pear-shaped and pedunclate. Probably, in life, the cup is capable of 

 being opened out to a considerable extent. Specimens of this species 

 were also obtained from 2160 fathoms in the South Atlantic. 

 Case A 1. Scrupocellcma reptans, or the Creeping Coralline (Fig. 10 a, b) forms 



branching colonies, creeping over rocks and seaweeds, and attached 

 by horny fibres often provided with curved hooks. The branches 

 are composed of cells arranged in a double row Each cell has the 

 membranous area of its front surface protected by a branched flattened 

 spine or operculum, and is produced and narrowed below ; at the 

 upper outer margin is a minute triangular avicularium. At the base 

 of the back surface is a small sack-shaped cell with a cleft at the 

 upper end, in which a horny bristle is articulated. The little cell 

 is termed a vibracular cell, and the bristle a vibraculum.* This 



* Vibraculum, a bristle. 



