794 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [8] 



sary to have the cones arranged in a series, each one with its toi> or 

 outlet considerably higher than the one into which it flowed, as in Fig. 

 •3 with the two cones, so that there should be sufficient motion in the 

 water to keep the eggs stirring. 



It may not be out of place to notice the fact that the eggs kept in the 

 stale water were almost entirely free from any fungoid growth. Why 

 these eggs should be favored in this manner is hard to say, aud may be 

 a question wortby of farther research. As regards the influence upon, 

 the development of the germ, there was a very marked difference in the 

 two methods employed. In the ice-chest, in the case of freshly impreg- 

 nated ova, segmentation would go on until the "mulberry" stage had 

 been reached, or until a small limb or i)rotuberaince of small cells had 

 l)een formed upon one side of the vitellus. After this there appeared 

 to be an entire cessation of all development as long as the egg remained 

 an the chest or until the vitellus disintegrated. 



In most cases disintegration or death did not take place for two or 

 three days, and up to this time the eggs had every appearance (other- 

 wise than that they did not develop) of being alive and in fair condition. 

 In the cone, however, development went on regularly and slowly from 

 the very first, aud continued until the water became of such a nature 

 :as to fail to longer nourish the embryos. 



This development was such that in about two hours the "mulberry" 

 stage had been reached ; in sixty hours the segmentation cap entirely 

 surrounded the yelk, and the young fish formed a prominent welt along- 

 one side of the vitellus ; in seventy-two hours the eyes commenced to 

 show ; and in one hundred and eight hours, or four and one-half days, 

 the tail portion, or that part free from the yelk, was as long as the por- 

 tion attached to the yelk, the eyes very prominent, with the crystalline 

 lens formed, the ear-cavity forming a semi-circular depression upon the 

 side of the body above the yelk, the protovertebrae numerous, and the 

 heart a small, single-chambered body, situated just back of the head, 

 S^etween the yelk and anterior end of the central canal, and just begin- 

 ning to exhibit regular although somewhat spasmodic beats. In an 

 ■embryo developed in fresh running water, at a temperature of 68'^ to 

 740, those stages would be passed through, respectively, in four, ten, 

 twelve, twenty, to twenty-six hours, showing a retardation in the case 

 of the embryo kept in water at 50° of from three to three and one-half 

 ■-days. At this rate the young fish in the colder water ought to hatch 

 out in about eleven to twelve days, and would probably, from their 

 slower growth, be more hardy than those hatched in three to three and 

 one-half days. It is to be regretted that these exi)eriments could not 

 have been begun earlier in the season, thus giving plenty of time for 

 thoroughly studying the questions and arriving at some definite results, 

 for although it would appear as if the method last suggested might 

 he successful, yet a trial seems to be absolutely necessary before under- 

 taking an ocean voyage. 



Washington, D. C, July 3, 1870. 



