164 Puget Sound Marine Sta. Pub. Vol. 1, No. 14 



in. EXPERIMENTAL RESULTS 



The experimental results are given in tables 2-8 where the essential 

 data are arranged in condensed form. Only about two-thirds of the ex- 

 periments are presented, but those not presented showed the same general 

 results. 



A. Resistance to Temperature 



The temperature experiments were performed in small dishes about 

 5 inches in diameter which were set into pans of sea water kept at the 

 desired temperature by a small alcohol flame. The addition of warmer 

 or colder water directly to the dishes was avoided where possible and great 

 care taken to prevent the warmer water from coming into contact with the 

 animal when it seemed best to add water of a different temperature. The 

 temperature was maintained within a half degree of the stated temperature 

 with little difliculty by simply watching it and manipulating the burner 

 and water supply according to the needs. 



In conducting such experiments much preliminary experimentation 

 must be carried on to determine the temperature at which the animals die 

 slowly enough to give good differential results, and at the same time die 

 within a period in which it is possible to watch them. If the temperature 

 is too high all animals may be killed at once, or if too low they may 

 tive for several hours, which makes absences necessary, rendering results 

 unreliable, and causes much inconvenience. 



In table 2 we find the specimens of the common coon-stripe shrimp 

 from different depths die in different lengths of time, those from shal- 

 lowest water living longest. The dying times are a series arranged in- 

 versely to the series of depths. An examination of the entire table shows 

 that the same rule holds good for all the other species and for the differ- 

 ent temperatures used. Further, when we compare the different species 

 at the level of their greatest abundance (as indicated by the relative num- 

 ber of individuals experimented on) we find that the species most abund- 

 ant at the greatest depths usually die quickest. 



Turning to table 3 we find there is a similar difference in the species 

 of crabs from the different depths. In a general way the crabs in the 

 deeper water die quicker than those from the shallower water. Cancer 

 oregonensis, however, when carefully collected from different depths does 

 not show the differences indicated by the shrimps. 



It is clear from the tables that there is a marked physiological differ- 

 ence between animals of the same and different species from different 

 depths. 



