DIATOMS AND LOBSTER REARING 15 
SESSIONAL PAPER No. 38a 
The usual habitat of Zicmophora is the surface of submerged seaweeds, especially 
Chorda filum, which is common in St. Marys bay along the shore near Long Beach pond. 
The source of this diatom is therefore the ocean water entering the pond through a 
pipe at every high tide. It has also been found attached to Copepods. It is rather 
Fig. 3. 
Licmophora Lyngbyei (Kutz) Grun, drawn under high 
magnification, showing the transparent gelatinous 
stalks. 
remarkable that during the summer of 1914 Licmophora formed probably less than 1 
per cent of the diatoms attached to the lobster larvez, while in 1915 it formed almost 
a pure culture, entirely replacing Synedra investiens of the preceding year. No satis- 
factory reason can now be given for the’ difference. During the summer of 1914 the 
rearing boxes occupied a position about 200 yards from their location in 1915. The 
sea-water surrounding them there could not, as in 1915, enter freely through a pipe 
reaching to the sea, but filtered through a wide sea-wall of boulders. Until we know 
more of the factors affecting the growth of the various kinds of diatoms, we can 
merely state these facts without relating them to results. 
5. PREVENTION OF THE GROWTH OF DIATOMS. 
Two methods of discouraging or preventing the development of the diatoms on the 
lobster larvee were briefly tested. One was the use of copper as an algicide, and the 
other was the reduction of light for the lobster larve. Both were very incomplete 
experiments, but the facts learned will be of service in future attempts at control. It 
has long been known that copper is an excellent fungicide, and its toxicity toward the 
