LOCOMOTION OF DENDRONOTUS GIGANTEUS. 



26l 



etc., but it refused all these except once, in which case it opened its 

 large fleshy lips in response to the touch of ccelenterate tentacles, 

 took them within its mouth, only to be ejected a little later. When 

 the animal was first found, and for several days afterwards, its 

 stomach was filled with air, which aided it in floating. It was 



FIG. 2. Photograph of Dendronotus giganteus O'Donoghue, lateral view. 



able, however, to submerge itself while in this condition. When 

 the air bubbles contained in the stomach after a few days had 

 disappeared, a little by little, the animal was able to float never- 

 theless. 



In conjunction with the study of qualitative chemical and physi- 

 cal stimulations in Hcrmissenda opalescence Cooper, I also studied 

 D. giganteus (vide Kjerschow Agersborg, 19220; for a full de- 

 scription of the species: O'Donoghue, 1921), and noticed inci- 

 dentally its remarkable mode of locomotion. During the first few 

 days in. the laboratory it was very active, and it was quite difficult 

 to make proper observations on its response to stimuli ; on the other 

 hand, it offered the opportunity to study its mode of locomotion 

 which is appended. 



Dendronotus giganteus has two distinct modes of locomotion. 

 The one, and the most commonly used, is that of swimming; the 

 other is creeping. The swimming movements are effected by a 

 regular twisting of the body in an undulatory manner, beginning 

 at the anterior end and passing gradually to the posterior. These 



