ZooL— Vol. II.] ROBERTSON— ENTOPROCTA. 343 



C. Movement. 



A living colony of Gonypodarm presents a scene of con- 

 siderable activity. Movement is greatest in the upper dila- 

 tations of the stalk, especially in the one at the base of 

 distal rigid portion. Two movements can be detected, one 

 from side to side, which is stiff and jerky, the other, a cir- 

 cular movement. In the first, the phalanx bends almost at 

 right angles to one side, then to the other, and in the return 

 to its original upright position it executes a partially circular 

 movement. It is not possible to say whether or not the 

 polypides respond to stimulus. Upon touching one with the 

 dissecting needle there seemed sometimes to be response, 

 but one could not be sure but that the movement might 

 have taken place without such stimulus. There was no 

 united, wave-like movement throughout the colony, such as 

 Ehlers describes for A. viacro-piLS. What the stimulus is, 

 it is difficult to say, especially when, as Ehlers also found in 

 A. macropus, one sees stems which have lost their calyces 

 execute the same movements as those which possess them. 



IV. Summary. 



1. The new genus Myosoma is distinguished by the pos- 

 session of a somatic ventral muscle which is continuous with 

 that of the stalk and forms the great ventral muscle. 



2. The somatic portion of the ventral muscle sends 

 branches to each side of the oesophagus. These form the 

 atrial retractors. It is probable that part of these branching 

 fibers are connected with the genital ducts. 



3. The musculature of the stalk consists of the longi- 

 tudinal muscle fibers of the ventral muscle, and also of 

 oblique fibers which proceed from the dorsal to the ventral 

 side. 



4. The tentacles contain each a pair of muscles, and the 

 sphincter of the lophophore attains an unusual development. 



5. Owing to the continuity of the ventral muscle, the 

 neck of Myosoma is unusually broad and holds the calyx 

 more securely upon the stalk than is the case in other Pedi- 

 cellinid£e. 



