Plvte III. 



Fig. 5. The larger specimen was takeu Sei)tem])er IS, 1899, 

 from a land-tile set in tlie mud on the shore (^^'ickford) at low- 

 water mark. It Avas placed in the land-tile on July 22, 1899, when 

 it was the size of the smaller specimen. The difierence in size 

 represents two mouths' growth (page 44). 



Fig. 6. One of the land-tile specimens planted July 18, 1899, 

 when of the size of the smaller s])ecimen in Fig. 5, and dug on 

 Septeml)er 10, 190O (i)age 44). It is, therefore, about a year and 

 three months old. 



