54 
ANNIE MATTHEWS. 
developed in succession below them, so that the youngest 
pinnule was always at the base (Text-fig. 15, P 1 and P 2 ). The 
numbers were variable in the two rows on any one tentacle, 
and on the eight tentacles of any one polyp. The tentacles 
were faint pink in colour at first, but this changed to pale 
cream during development. Some polyps seemed to develop 
rather quicker than others, as did the planulm. When fully 
grown the measurements of the solitary polyp are only about 
half the corresponding ones of the colonial polyp, i. e. about 
Text-fig. 16. 
Solitary polyp, settled fourteen to twenty days ; tentacles 
bearing six pinnules, diameter of base T2 mm. Lateral view, 
well expanded (from finger-bowl), X 10. 
6 mm. in height, tentacles 3 mm. long, and diameter of base 
T2 mm., while it is much more opaque, and consequently the 
stomodseum shows less plainly and the mesenteric filaments 
are obscured. As soon as the tentacles are long enough, they 
curl gracefully about in the water, seeking food (Text-fig. 16). 
Any vibration causes them to retract in part or wholly, 
the polyp in a complete state of retraction appearing as a 
small pink mound with an opaque centre. The spicules in 
the tentacles and body nearly meet in the solitary polyp 
(Text -fig. 14, T. Sp., and B. Sp.), whereas they are widely 
separated in the individuals of older colonies. Some 
