380 



SELIG HECHT 



smooth dogfish, Mustekis canis, I was convmced that in this 

 species the form of an individual remained constant throughout 

 its Hfe, and that here, too, weight was a function of form. 



It seemed therefore desirable to attempt a more extensive 

 consideration of these relationships as found in fishes. This I 

 have done. Other matters, which came up in the course of the 

 investigation, have an important bearing on the theoretical inter- 

 est of the subject, and will be dealt with below. 



MATERIAL AND METHODS 



The selection of species for study was dependent on their 

 abundance, and on the range of size that they offered. During 

 July and August of 1913, at Beaufort, N. C, six species were 

 found which fulfilled these requirements sufficiently well. As 

 was to be expected, a random catch was composed mainly of 

 medium-sized individuals. In order, therefore, to have a series 

 covering as large a range as possible, the specimens were, in a 

 measure, selected according to length, so as to give approxi- 

 mately equal numbers of all the lengths represented. Table 1 

 gives the family, specific, and common names, and also the num- 

 ber of individuals of each species used in this study. 



The weights were taken on a platform balance reading directly 

 to 0.1 gram. More accurate weighings were unnecessary. All 

 of the measurements, except those of length in the case of the 

 larger fish, were made with dividers. For the determination of 

 the length of the larger specimens, the fish were placed on a 



