336 William E. Kellicott 



Here again there seems no certain distinction between the sexes, al- 

 though it is possible that in the largest males the rectal gland is slightly 

 smaller than in females of corresponding sizes. The plate shows that 

 in males of 2000-3000 grams the records for the males are mostly below 

 those of the females, although to be certain of a difference here a larger 

 number should be examined. 



The Pancreas. — The average weight of the pancreas at birth is 0.061 

 gram: the maximum weight observed is 7.78 grams. The distribu- 

 tion of weights between these extremes is quite uniform, but Plate 4 

 shows that this is along a slightly curved line. The total increase in 

 the pancreas weight was more than 127 times. 



The curve of relative weights is quite similar to that of the heart. 

 At birth the ratio is 0.08 per cent; it increases very rapidly until the 

 total weight reaches about 200 grams when it reaches a maximum of 

 0.137 per cent. Then falling more slowly than the heart it is about 

 0.105 in fish of average size, higher still than at birth, and finally drops 

 to probably about 0.075 per cent. The largest specimen measured showed 

 an actual ratio of 0.092, but inspection of the curve shows that this is 

 considerably in excess of the expected average as indicated by fish of 

 5000 to 7000 grams, among which it averages 0.0787 per cent. We may 

 therefore assume about 0.075 as the probable final ratio for comparative 

 purposes. This is not far below the ratio at birth, but it is only about 

 one-half the maximmn. 



There is no distinction betAveen the sexes in either absolute or relative 

 weight of the pancreas. 



The Spleen. — At birth the average weight of the spleen is 0.097 gram. 

 Even at this time there is indicated the condition of great variability 

 which continues throughout the series. Thus at birth the extremes 

 in weight are 0.06 and 0.15 gram among individuals whose total weights 

 vary only between 69.5 and 84.0 grams. And we find that while the 

 curve given by the serial weights is regular — see Plate 5 — the individual 

 weights are distributed about it much less closely than in any of the 

 organs yet considered. We find the spleen of the heaviest fish is not 

 the largest absolutely. The largest spleen weighed 12.36 grams, and 

 was found in a female weighing 3638 grams, less than half the weight 

 of the heaviest fish. This was an exceptionally large spleen and for 

 purposes of comparison we should consider rather the condition shown 

 by the curve to be more typical. Thus at 8400 grams total weight the 

 spleen averages about 9.75 grams, giving an increase in the entire series 

 of more than 100 times. 



