344 L. MURBACH. 



easily effected anywhere along the tapering foot end. No 

 other part of the hydrocaulus seems to be used to " make 

 fast." 



The predominant colour of the polyp is pale to bright pink, 

 resembling many Tubularians in this respect. As commonly 

 occurs elsewhere, the colour is localised mostly in the endoderm 

 cells of the body, showing through the more transparent 

 ectoderm of the periphery. In another part of this paper it 

 will appear that greater activity in any part of the body is 

 marked by greater depth of colour. In a general way this is 

 evident in the more active digestive region of the hydranth. 

 An apparent exception are the intense pigment spots at the 

 free ends of the gonophores. 



The regions of the body are well marked into hydranth, 

 bearing besides the mouth two circlets of tentacles and the 

 gonophores, and into hydrocaulus (cf. fig. 1). At the union 

 of these two main divisions of the body there is a thickened 

 collar-like portion studded with nettling organs. From this 

 structure to the free rounded foot end the hydrocaulus is 

 covered with a kind of rudimentary perisarc. The hydro- 

 caulus is never branched. 



In size the average adult animal is from 1 to Ig cm. long, 

 and 1 to 14 mm. thick. Of course the size varies with the 

 degree of expansion or contraction ; the measurements were 

 therefore made from a moderately expanded animal. 



Locomotion is slow though definite, and not very extensive. 

 The animal seems to progress by leaving its tubular secretion 

 behind, stepping on it, as it were, so that a relatively long 

 piece of the tube, plainly marked by adhering foreign matter, 

 indicates its progress. The movements of parts of the body 

 are slow, — its tentacles, for example, swaying to and fro in 

 search of prey. When disturbed the hydranth and tentacles 

 contract first, and if the irritation is continued the whole 

 animal contracts into a small mass. 



