114 SIDNEY F. HARMER. 



presence of remarkable brown vesicles in various parts of 

 the polypides and ovicells (see figs. 20, 22), provided that the 

 material was prepared with certain reagents. As I have, 

 moreover, found these vesicles also in decalcified preparations 

 of T. aperta, it is highly probable that they are of normal 

 occurrence in a portion of the genus at least, and perhaps 

 throughout the whole genus, and that they play some important 

 part in the physiology of the colonies. What that part may 

 be is somewhat doubtful. I have hesitated whether to consider 

 them as reserve-stores of nutritive material or as excretory 

 bodies ; but the balance of evidence appears to me to incline 

 towards the latter view. 



I first found the vesicles in sections of material which had 

 been prepared with corrosive sublimate. The vesicles are 

 with this preparation excessively resistent, and therefore retain 

 their form and their yellowish-brown colour in sections of 

 colonies which have been decalcified with nitric acid, embedded 

 in paraffin, and stained with hsematoxylin or borax carmine. 

 They are found principally in one of three places : (a) beneath 

 or in the terminal membranes of the zooecia and buds; (b) 

 beneath or in the terminal membrane of the ovicell; (c) in the 

 tentacles. They occur in the first two situations in T. p 1 u m o s a, 

 T. liliacea, and T. phalangea; and in the first, at least, in 

 T. aperta, of which I have not examined sections. So far as 

 I know at present the occurrence of the vesicles in the tentacles 

 is almost restricted to T. plumosa; and so constant have I 

 found this character (during the spring months) that I have 

 used it as a means of distinguishing sections of this species 

 from those of T. phalangea. In one case, however, excretory 

 vesicles occurred in the tentacles of a specimen of T. pha- 

 langea, determined as such by the characters of its oceciostome. 

 The colony contained an old ovicell (early stage G), but most 

 if not all of its polypides were degenerating, and the whole 

 colony was unusually heavily charged with excretory vesicles. 

 It thus appears that the vesicles may occur in the tentacles of 

 T. phalangea under certain circumstances; but I think it is 

 none the less true that in the early spring, on the coast of 



