No. 447.] H AMINE A SOLITARIA SA V 



just before the egg-laying time, and their equally sudden dis- 

 appearance after the egg-laying time. They simply rise to the 

 surface and swim away. 



In the summers of 1897 and 1898 most of the specimens 

 obtained by me were collected in the larger of the two so-called 

 "oyster ponds" near the Marine Biological Laboratory. 

 Although a large number of capsules were taken from this 

 place, over one hundred capsules were gathered from another 

 locality and put into this lagoon in order to assure an abundance 

 of material in succeeding seasons. In the summer of 1899 no 

 capsules could be found in this lagoon, in the summer of 1900 

 three capsules were found here, but all of the eggs had died 

 before reaching the twenty-cell stage ; the tide flows freely into 

 the lagoon thus keeping the water comparatively fresh. The 

 drainage from the Marine Biological Laboratory flows into an 

 adjacent lagoon and it is possible that the water seeping through 

 may have some poisonous effect which kills the eggs and has 

 destroyed or driven out the animals themselves. 



The Bulla found on the sandy bathing beach at Buzzard's Bay 

 occurs about half an inch below the surface of the sand ; usually 

 near the capsule, which is the only indication of the presence of 

 the animal. 



Genera/ Morphology} --I'i is not my purpose in this section 

 to go into the details of the various systems of organs excei)t in 

 so far as they are directly related to the development of the 

 egg ; I purpose, however, to give a brief sketch of the general 

 form of the animal. 



Probably the most striking feature of this species is its color, 

 which is a golden gray thickly mottled with dark broun and 

 occasional orange spots; one might almost say that the gray 

 background looks as though sprinkled with fine sand. The 

 shell is translucent and slightly striated spirally ; it is not at all 

 glossy or shiny. One would hardly expect to find much of a 

 shell in a tectibranch, but in solitaria the reduction of the shell 



