A NEW PRINCIPLE OF AOUICULTURE. 



777 



A few eggs of Fundulus heteroditus were fertilized on July 27 and were 

 placed in the original filter car. They were floated near the surface in a shallow 

 bag of netting somewhat similar to that described in the case of Menidia. The 

 eggs hatched on August 5 and 6 and the fry all lived in healthy condition until 

 they were taken out at intervals and preserved. The daily averages of length 

 for the first ten days are as follows: 



Mm. 



Augusts 4-9^ 



August 6 5.07 



August 7 5-4° 



Augusts 5.35 



August 9 5.56 



August 10 5.37 



August II 5.88 



August 12 5-92 



August 13 5.98 



August 14 6.25 



August 15 6-30 



Specimens of this lot have continued to live in one of the cars until the 

 date of writing (September 19). 



On July 17, 56 young toadfish, measuring from 15 to 17 millimeters, which 

 had been raised from the eggs in a small car, were transferred to the original 

 filter car. At more or less irregular intervals during the next four or five weeks 

 specimens were taken out and measured. The following table of individual 

 and average measurements indicates the rate of their growth : " 



Mm. 



August II 26.0 



August 14 26.5 



August 21 & 19.0-33. 7 



July 17 (56 specimens) 15. 0-17. o 



July 30 19. o 



July 31 22.5 



August I 18.7,22.0 



In order to test these cars with as many kinds of fishes as possible, we 

 introduced the young of some other species in lieu of fish eggs, which could not 

 be obtained in great variety at this season of the year. On July 17 a lot of 

 pipefish taken from the brood pouch of a male were put directly into the original 

 filter car. The individuals appeared to be of practically equal length and 

 measured 10 millimeters. They apparently all lived and, like the other speci- 

 mens in the cars, continued to thrive, showing no sign of disease, until they 

 were taken out, on August 21. 



The following data show the rate of growth as indicated by the average 

 sizes at the end of irregular periods. No food was given to them except that 

 which came in with the water by means of the chain of buckets. 



July 17 10. o 



July 18 II. 4 



July 20 21.8 



July 23 24.5 



July 25 27.5 



July 27 26.5 



July 30 44.0 



July 31 46.1 



August 2 52.6 



August 6 61.6 



August 8 58.6 



August n 67.4 



August 15 67.2 



August 20 69. 4 



Septembers '^71-3 



September 14 « 70. o 



" I am indebted for these measurements to Mr. H. C. Tracy. 



b Average, 30.21 mm. Fifty-four specimens out of 56 put into the car were recovered. 



c Measurements taken after transference to new car. 



B. B. I'. 1908— pt 2- 



