302 NOTES AND MEMORANDA. 



these observations, and extonded them to the whole gi'oup of Eudo- 

 proct Polyzoa. 



In some Pedicellhice which he observed the vibratile organ was 

 double, and situated in the cavity of the body in the space comprised 

 between the oesopbagus, the stomach, and the matrix. It was com- 

 posed of a short tube, ciliated on the interior surface (swollen in 

 the middle), which on the one hand opened into the matrix not far 

 from its external orifice, and on the other opened obliquely into the 

 cavity of the body, by a mouth slightly bell-shaped and furnished 

 with active vibratile cilia. 



This organ, provided with a vibratile mouth, and placing the 

 cavity of the body in communication with the exterior, has all 

 the characters of a segmental organ. It appears very early in 

 the bud. When the stomach is only outlined, and before the ten- 

 tacles appear, a ciliary movement is seen at the place which it sub- 

 sequently occupies. 



M. Joliet observed the same organ in a second species of 

 Pedicellina, and in Loxosoma, and he considers that in the Endoproct 

 Polyzoa may be regarded as constant the presence of an organ 

 widely distributed in the worms. In face of the attempts which have 

 been made in later years to bring the Polyzoa and the Annelida 

 together, it seems to him useful to put forward his observations. 



Power of Locomotion in the Tunicata. — Mr. W. Macleay, F.L.S., 

 has observed,* with some astonishment, that large Ascidians which 

 he found strewn at low water on a sandy beach after a storm, are or 

 seem to be capable of a certain amount of locomotion — they do 

 change their positions most undoubtedly ; in doing so they leave 

 upon the wet sand a distinct track in accordance with the weight 

 and size of the mass, and these movements are not in any way 

 attributable to winds or waves. He at first thought it possible that 

 the movements might be due to the agency of some of the animals 

 adhering to the outside of the mass, but he found that the only 

 organic attachments, excepting a few small shells, were clusters of 

 simple Ascidians utterly incapable, therefore, of combined action, and 

 much too small for their individual efforts to produce any effect. 



Notwithstanding, however, this apparently convincing evidence, 

 he is indisposed to believe it possible that an animal so completely 

 shut up in a thick coriaceous unmuscular sac, can have any power of 

 external movement, nor is it likely that such a power would be 

 possessed by an animal whose whole life (except in infancy) has to 

 be passed firmly rooted to the bottom of the sea, and he hopes that 

 some one having the leisure and opportunity will endeavour to solve 

 this problem. 



Extension of the coiled Arms in Rhynchonella.— Years ago Von 



Buch recorded that Otto Frederic Miiller had observed the Brachiopod 

 Bhynclionella iisittacea protrude its arms beyond the anterior borders 

 of the shell. This single observation was not widely accepted, and 

 many doubted the possibility of the arms being exsertcd in this 



* ' Proc. Linn. Soc. N. S. Wiil,.-^,' iii. (187S) 55. 



