236 Dr. J. D. F. Gilchrist on 



Habits of the Zooids and Buds. 



Some opportunity was offered of studying the habits and 

 behaviour of the zooids and buds in the living condition, 

 though much of the material, when brought on board, 

 showed few living animals, and these were more or less in a 

 moribund condition, many having dropped to the bottom of 

 the vessel in which they were placed. Occasionally, how- 

 ever, a specimen was got — probably taken just before the 

 trawl was hauled — covered with living animals. The 

 appearance presented in such cases was very striking, and is 

 probably characteristic of the normal state of the animal. 

 The zooids and buds were on the surface of the ccenoecium, 

 and imparted to some of the more crowded brandies quite a 

 black appearance. When examined more closely, with the 

 aid of a lens, the general aspect was that of a mass of small 

 black threads with swollen extremities, or a number of small 

 black pins scattered indiscriminately over the surface of the 

 ccenoecium. These were the stalks and expanded proboscides 

 of the buds. Some of these stalks were about 4 or 5 mm. 

 in length, and ended in a large sucker-like proboscis, which 

 was firmly adherent to the surface of the coenoecium, at some 

 distance from the zooid to which it belonged. The zooid 

 itself was found at the entrance of the tube, on the spine, or 

 even at some distance from the tube. The general appear- 

 ance suggested that the buds were acting as anchoring 

 individuals for the fully developed zooid. No movement was 

 observed in buds or adult zooids, with the exception of an 

 occasional spasmodic jerking of the arms, the significance of 

 which will be discussed later. When the attached proboscis 

 of the bud was gently touched by a needle it at first showed 

 no signs of reaction, except a slight withdrawing movement ; 

 but, on the irritation being continued, it suddenly relaxed its 

 hold on the surface of the ccenoecium, and was withdrawn 

 rather rapidly towards its point of attachment to the zooid by 

 a spiral coiling of the stalk, the proboscis preceding or being 

 closely applied to the stalk, as they both disappeared into the 

 coencecial cavity. This movement was apparently the result 

 of a contraction of the muscles of the stalk, but in one or two 

 cases it was observed to be continued as an active crawling 

 movement, which was seen under the microscope to be due 

 to the action of the ciliated surface, to be noted more fully 

 below. In the withdrawal of the proboscis from the surface 

 a quantity of viscid mucus-like substance was observed at 

 the point of attachment, and if this substance touched the 

 needle it adhered to it somewhat tenaciously. 



