98 



Papers from the Department of Marine Biology. 



parts change as the body becomes heavier. The greatest increase in 

 relative weight is made by the velar lobes, while those made by the 

 mouth-organs and the umbrella follow in the order named. It should 

 be noted that, although the mouth-organs show the greatest weight 

 during most of the animal's life, yet in the earlier period, where the 

 entire body weighs less than 0.5 gram, the umbrella has a greater 

 weight than the mouth-organs. 



TABLE 1.- 



-Different body-weights of ike lun-mal Cassiopea, the weights of mouth-organs, 

 umbrella, and velar lobes. 



The graphs in figure 1 show that the growth in weight of these three 

 parts on body-weight is almost linear. It would be interesting to 

 determine how the growth curve of Cassiopea with respect to age 

 appears, but for the necessary data we must await future investiga- 

 tions. 



GRAMS 



160- 



ZO 40 50 80 



;oo 



:20 140 160 130 200 220 



240 260 

 -160 



140- 



120- 



100- 



80- 



60- 



40- 



20- 



x Mouth organs? 

 o Umbrella 

 Velar lobes 



.2- 



20 



60 80 100 120 140 150 130 2CO 220 240 



BODY WEIGHT.GRAMS 



140 



-120 



-100 



FIG. 1. Showing the growth of three parts of the body according to the increasing 



weight of Cassiopea xamachana. 



