FORM AND GROWTH IN FISHES 399 



in animals having determinate growth, the external from changes 

 continually during the period of growth, and as soon as the form 

 becomes constant, growth ceases. 



8. The ratios giving the dimensions of the parts of the body 

 in terms of length, show that the forms of the different parts 

 (except depth) are quite constant in the different species, indi- 

 cating their conformity to a generalized fish-form. This is corre- 

 lated with the known similarity in the 'entering angle' (Parsons) 

 of the different species. 



9. Depth, however, varies from species to species, and seems 

 to be largely responsible for the special form of a species. 



The data for this contribution were secured at the Beaufort 

 Laboratory of the Bureau of Fisheries, during the summer of 

 1913. To the commissioner, Dr. H. M. Smith, I desire to express 

 my thanks for the opportunity to work at the station. I am 

 indebted to Dr. E. L. Mark and to Dr. H. W. Rand for a critical 

 reading of the manuscript. 



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