.lincrican i'ishcrus Soiiclj. 91 



was fouml that al)out 30 per cciil. of this loss was occasiom'd l)\ 

 insufficient lood supply, that is, iIk' yelk sack hciiij;- uiulcrsi/A', 

 the albumen would become absorbed when the embryo would 

 starve to death. This loss goes on from the early formation of 

 the embryos up to the time of hatchins;-, those with the smaller 

 sacks dyins^ first and the others later on. 



Malformation causes about 20 per cent, of the loss, bci^innin^; 

 early where the embryo is very poorly ors.;^anized, perhaps having; 

 merely the semblance of an org^anization, with the abnormal brain 

 and a rudimental spinal column and yet with a heart and a svs- 

 tem of blood vessels. The c\es in these more erratic forms are 

 usually wantiuii', and if present are very imperfect, these or<j^ans 

 being" among the first to show malformation, while the auditory 

 apparatus is among the most perfect. 



About eight or nine per cent, of this loss is caused by ruptured 

 yelk sacks, ruptured blood vessels and aneurisms. 



With about 40 per cent, of this loss the writer was iniable to 

 arrive at the cause. His work was all done in gross, not having 

 a microtome or other appliances for making sections, and not 

 being stifficiently versed in the work to have made use of them 

 if he had been thus supplied. It is probable that one well versed 

 in the various sciences called into action in this w^ork and with 

 better appliances could deternnne the cause of death in the greater 

 portion of this remaining 40 jicr cent. 



The writer has come to the conclusion that, as in the higher 

 forms, nearly all this loss is the natural weeding out of the more 

 weakly individuals, through that inexorable law which provides 

 for the survival of the fittest, and it therefore follows, if this be 

 true, that no amount of care on the part of the fish culturist can 

 do more than cut this loss down in a small degree. It is prob- 

 able that care in taking and handling the eggs would reduce the 

 number of malformations and ruptured velk sacks to some ex- 

 tent, but in the main the death of eyed eggs results from natural 

 causes, which no amoimt of care on the part of the fish culturist 

 can prevent. 



The writer would reconunend that fish culturists use the 

 camera in connection \\ith the microscope and thus place the 

 result^ of their labors in a more ])ermanent form. 



With a reasonably good microscope and any camera which 

 has facilities for handling dry plates, photo-micrographs can be 

 made by removing all the lenses from the camera, which can be 

 connected with the microscope cither jUM-pendicularly or horizont- 

 all\- according to the egg. whether l)est viewed from side or top. 



