No. 5.] THE HABITS OF PYCNOGONIDS. 207 



SUMMARY. 



1. The three forms treated are more or less adapted in color 

 to their several habitats. 



2. Swimming is accomplished by a treading movement of 

 the legs, which tends to propel the animal dorsalward. 



3. The stroke of each of the legs is the same in character, 

 but is stronger in the anterior legs than in the posterior. 



4. Crawling is accomplished by the same action of the legs 

 as swimming, when the action is not strong enough to raise 

 the animal from bottom. The anterior legs are most effective, 

 pulling the animal forward ; the action of the posterior legs is 

 a hindrance. 



5. Both Anoplodactylus and Pallene are strongly positively 

 phototatic. 



6. In crawling towards the light the animal proceeds with 

 the anterior end in advance. If not oriented in this direction 

 at first, it becomes so oriented by making a short circle, in 

 every case towards the light. This means that those legs away 

 from the light beat stronger than those towards the light. 



7. In swimming towards the light the animal moves approxi- 

 mately backwards, with the anterior end somewhat raised. 

 The amount it raises depends upon the activity of the indi- 

 vidual and the slant of the rays of light. 



8. This orientation is accomplished by the same actions that 

 produce orientation when crawling, except that they are more 

 vigorous, raising the animal from the bottom. 



9. The transfer of the eggs from the female to the male is 

 a comparatively simple process. 



ANN ARBOR, MICH., Nov. ^3, 1900. 



