NO. 19.] ECHINODERMS OF CONNECTICUT. 41 



There were larger specimens than those indicated, and also 

 smaller, for at all times there were some individuals which were 

 only a third as large as the others, and all intermediate stages 

 occurred between the smallest and the largest. Similar series 

 could be obtained along the seashore at any time during the 

 summer and fall. 



By varying the amount of food supplied, Professor Mead was 

 able to prove that the rate of growth depended directly upon the 

 amount of food available. In this respect the starfish behaves 

 quite differently from the higher vertebrate animals, for the 

 starfish can assimilate many times as much food as is necessary 

 for keeping it in good condition, and all the food not required 

 for the maintenance of the bodily functions is used in the manu- 

 facture of new tissues, whereby a rapid growth results. Yet a 

 starfish will live and remain in apparent health for months with 

 scarcely any food whatever, although no growth takes place 

 under such circumstances. 



When the usual food supply becomes scarce, the larger star- 

 fishes show no hesitation in devouring smaller individuals of 

 their own kind. 



In Fig. 3 are shown outlines of two individuals of the same 

 age, five and one-half weeks, the small star on the left repre- 

 senting a starfish to which but little food was supplied, while 

 the larger figure shows the size which a well nourished specimen 

 may reach at the same age. 



Explanation of Plate VI. Rate of growth of starfish, Asterias forbesi. 



A series of young- starfish to show the rate of growth of well-nourished 



individuals during the first four months of life. All natural size. 



Figs. 1 to 3. Small individuals during the first week after having com- 

 pleted the free-swimming stage, July 1. 



Fig. 4. Specimen from eelgrass two weeks later, July 15. 



Fig. 5. Specimen reared in submerged car about three weeks after the 

 completion of the free-swimming stage, July 15. 



Fig. 6. Similar specimen three days later, July 18. 



Fig. 7. Large specimen from car when one month old, July 26. 



Fig. 8. Similar specimen on August 2. 



Fig. 9. Similar specimen on August 18. 



Fig. 10. Same on September 5. 



Fig. 11. Same when three months old, September 26. 



Fig. 12. Largest specimen reared in submerged car at the age of four 

 months, October 25. 



(After Mead.) 



