Reactions of I so pods 



449 



Both the individuals whose reactions are recorded in Table 

 III were active and vigorous animals and the records shown are 

 typical of the two species. It will be noted that Asellus was less 

 sensitive than C^ecidotea to all the currents and scarcely sensitive 

 at all to current No. 4, while Caecidotea was extremely sensitive 

 to the four currents and was only slightly less sensitive to the 



TABLE III 



Reactions of Asellus communis, No. J, cJ', length g mm. and Coecidotea stygia,No. 7>f5', length 8.8 mm- 



to mechanical stimulation by small, locally directed currents of water. The first column ot the left indicates 



the parts stimulated. In the second to sixth columns are indicated the di^erent currents used {Nos. I to 5) 



and the vigor of the reactions to these currents when directed upon the parts of the body indicated 



Asellus Communis, no. 7, 6^, 9 mm. 



Temperature of Water, I2°C. 



CURRENTS USED 



No. I* 



No. 2 



No. 3 



No. 



No. 5 



Little 



Extremely 



1 . Flagella of the antennae. 



2. Basal segments of the 



antennae 



3. Legs ! Strongly 



4. Top of head Extremely 



5. First free body segment| Strongly 



6. Other body segments.. Strongly 



7. ."Abdomen Strongly 



8. Uropods Strongly 



C.«CIDOTE.-\ StYGL\, no. J, C?, 8.8 MM. 



Temperature of Water, I2°C. 



CURRENTS USED 



No. I 



No. 2 



No. 3 



No. 4 



No. 5 



1. Flagella of the antennee' Not 



2. Basal segments of the 



antennae Extremely 



3- Legs 1 Extremely 



4- Top of head : Extremely 



5. First free body seg- 



ment Extremely 



6. Other body segments. 



7. Abdomen 



Extremely 

 Extremely 

 Uropods I Extremely 



Not 



Extremely 

 Extremely 

 Extremely 



Extremely 

 Extremely 

 Extremely 

 Extremely 



Not 



Extremely 

 Extremely 

 "Extremely 



Strongly 

 Strongly 

 Extremely 

 Strongly 



Not 



Extremely 

 Extremely 



Extremely 



Strongly 

 Strongly 

 Extremely 

 Extremely 



Not 



Strongly 



Not 

 Strongly 



Not 

 Not 

 Not 

 Not 



*For a description of these currents, see page 448 



