88 



Pub. Pucjet Sound Biol. Sta. 



Vol. 2, No. 37 



In each of 2 cases the reaction was positive to the sea water end. While 

 a positive reaction to mild alkaline conditions is shown above ; no optimum 

 could be determined, although it lies not far from neutrality. Reaction to 

 the ends (thigmotaxis) is stronger than to differences in acidity. 



Resistance to salinity 



Several experiments were performed with reference to salinity. The 

 first group dealt with resistance to fresh water. 2 of the rectangular 

 pans described were filled to a depth of several centimeters with sea 

 water and spring water respectively and the temperature maintained the 

 same in the 2. In these experiments 1 or 2 blennies died after 1 hour and 

 45 minutes, and the other after 2 hours and 15 minutes. Of 5 individuals 

 3 died at the end of 3 hours, the other 2 at the end of 1 hour and 59 

 minutes and 4 hours respectively. Practically all of the 7 lived 2 hours 

 or more. Those in the control pans remained normal. In a compara- 

 tive trial 4 fish secured at 30 to 60 fathoms (Tcelinus horealis and Xeneret- 

 mus alaskanus) survived 1 hour and 59 minutes and 2 hours respectively. 

 This is another instance in which the blennies are better fitted for a shore 

 habitat than the deeper water fishes. Shore animals are often subjected 

 to variations in salinity. 



A still more striking experiment was carried out with differences in 

 salinity, 10 blennies apparently in the same physical condition were 

 used to determine resistance to salinity. 2 were placed in each of 5 

 shallow glass dishes containing water grading from half-evaporated sea 

 water to spring water. This time scarcely enough water was used to 

 submerge the blennies. Record was kept for 4 days, after which time 

 the fish could not properly be considered as normal. In table 2 the 

 number at the left refers to the dishes, containing 2 individuals each, 

 while the time indicates the end of the period through which they were 

 observed. 



The sea water used contained about 16.65 grams total chlorine per 

 liter. Thus the waters of the region are less saline than average sea 



