The Lancelet. 229 



Edwardsii (Goodsir), but have not yet managed time, 

 and now I fear the season is too far gone. However, 

 I intend to take the first opportunity, and I have 

 some hope of finding them. Goodsir says they were 

 taken at the mouth of the Firth of Forth, and that 

 Cuma Edwardsii (Goodsir) were the most common,* 

 and further that they were of a pale straw colour, 

 indicating, I think, a sandy habitat. Therefore, with 

 a little perseverance and proper appliances, and with 

 the knowledge I have of their habits, I think there is 

 some chance of finding them. 



" In regard to the tenacity of life of the Amphioxus ; 

 in the first place I kept one in captivity for upwards 

 of twenty months in a small earthen preserve-pot, 

 measuring only 3^ inches deep by 3^ inches wide, 

 filled with sea-water, including one-third of small 

 gravel. It was placed in a small sitting-room where 

 gas and large fires were burning from sunset till ten 

 or twelve at night, when they were both extinguished. 

 This was continued in the winter months with few 

 exceptions, causing the temperature in the twenty- 

 four hours to be very unequal. At first the water 

 was changed every other week or so, but, from a 

 listless state these changes seemed to occasion, the 

 practice was discontinued, and only at long intervals 

 a little fresh water was added to make up for 

 evaporation, and at last after a very long neglect 

 it died, when we found that it had been living in 

 water holding in solution nearly the double of the 

 usual quantity of salt present in sea-water. But the 



* That is, the most common of the three species which Goodsir 

 discovered. 



