LOCOMOTION OF DENDRONOTUS GIGANTEUS. 263 



lations which passed from the posterior end of the foot to the ante- 

 rior. The animal adhered to the substratum by sucking to the 

 extent that it did not pass out of the dish when the water was 

 poured out of it. In creeping, local undulations are set up in the 



FIG. 4. Photograph of Dendronotus giganteus O'Donoghue showing the loco- 

 motor wave during swimming passing toward the posterior end. All the 

 photographs are of living specimens, photographed through the water, by Dr. 

 Myrtle E. Johnson, State Teachers College, San Diego, Calif. The photographs 

 were taken at the Puget Sound Biological Station, July, 1921. 



form of series of areas adhering to the substratum, and intervened 

 by non-adhering parts which travel gradually toward the anterior 

 end. The method of creeping may be classed as direct rhythmic 

 locomotion, to use the terminology of previous writers on this sub- 

 ject, although it is not possible to classify this exactly at this time. 

 -jjKThe method of rhythmic locomotion is accompanied in this case, I 

 believe, by ciliary action. The foot in Dendronotus giganteus is 

 highly ciliated. No slime is produced during locomotion or at any 

 other time. The foot is also uniformly ciliated in Mclibc leoninu 

 Gould (Kjerschow Agersborg, 19210, 1922). Ordinary locomo- 

 tion in Mclibc is effected by the ciliary action of the foot. The 

 ciliated epithelium is innervated with nerve fibers from the pedal 

 nerve-net (Kjerschow Agersborg, 1922). 



Swimming as a means of locomotion is common among pelagic 

 forms which are then frequently provided with secondary organs 



