DEVELOPMENT OF THE WHITE-FISH. 521 



brown confervoid growth had developed in the water, and the young fish attempting to swallow 

 it always got it entangled in its gills and soon died. 



" In my absence, I visited Clarkston ami purchased for private parties from Mr. N. W. Clark 

 one thousand young Trout, which I brought safely to a brook two miles north of Wankegan, Illinois. 

 Mr. Clark gave me one hundred and fifty young White-fish, most of them with the yelk sac only 

 partially absorbed. The difference in temperature evidently made some difference in the rapidity 

 with which the umbilical sac disappeared, as the young fish I had carried home were in the same 

 stage of development, April 14, as when I had visited Clarkston previously. Now, May 1, the . fish 

 in Mr. Clark's troughs still retained considerable of the sac, while on the 28th of April the young 

 fish in the jar had lost it entirely. The jar had been kept in a moderately warm room, with a 

 temperature of about 65, while the water in the troughs at Clarkstou flowed from a pond that had 

 been covered with ice until within a few days previous. 



(Hi) Bate of Growth. "Further research for the young fish was unavoidably delayed until the 1st 

 of July. Towards the end of June, from a seine-haul at Waukegau, a specimen of Coregonus allmx, 

 measuring eight and three-tenths inches in length, one of C. qtiarlrUati-raU-n, measuring seven and 

 four tenths, and one of Coregonus harengus, measuring three and four-tenths inches, were obtained. 



"At Sault Ste. Marie, Michigan, on July 2, with an Indian in a birch canoe, the vicinity both 

 above and below the rapids was explored in tli current and in the still water and along the shores, 

 to find the smallest grade of White-fishes that were to be had. Along the shore, in the sharp 

 current, schools were found of which the smallest taken measured four inches and nine-tenths, 

 and the largest six inches and one-tenth. It was quite evident that they had all been hatched the 

 same season. Another excursion in the birch resulted in nothing materially different. The 

 minimum measurement of the next grade taken was eight inches and three-tenths. 



"At Shoal Island, one of the Apostle Islands of Lake Superior, a White-fish was taken from 

 the pound-net about the middle of August measuring six inches in length, and another measuring 

 six aud one-half inches. 



"On the .'id of December, at Point Edward, Canada, at the outlet of Lake Huron, two speci- 

 mens of Coregonus albiis were obtained from a seine, one measuring six inches and eight-tenths, 

 and the other seven inches and seven-tenths. 



"It is very probable that the Shoal Island fishes of August and the Point Edward ones ol 

 December 3 were the larger-grown individuals of the same generation as those taken at Sault Ste. 

 Marie in July. The difficult point to decide was in what year the beginning of this generation 

 should be placed. 



"The only positive data with reference to the growth of W T hite-fish are found in the observa- 

 tions of Mr. Samuel Wilinot, of Newcastle, Ontario, in charge of the government hatching house of 

 Canada. Mr. YVilmot reports that in November, 1SG8, he placed a quantity of spawn in the hatch- 

 ing troughs for an experiment, and in the following March and April a large number of young fry 

 made their appearance. He failed in finding food adapted to the young fish, but a number that 

 escaped through the screens were carried down to a small pond, where they seemed to thrive, 

 and soon became well-developed young fish. In the month of September they were exhibited at 

 a fair in London, Canada. They were then about five inches long. In December the young fish 

 had attained the length of seven inches. 



"Mr. N. W. Clark, of Clarkston, Michigan, visited Wilmot's hatching-house in 1871, and in an 

 address before the house of representatives of Michigan said : ' Enough is known, from the success 

 of Samuel Wilmot, esq., of Canada, to sustain us in the assertion that they (the White-fish) in- 



