74 
In some cases the rate of boring was stated to depend on the age 
of the worm or to vary with the hardness of the timber. All were 
agreed, however, that it was about } inch daily. 
On 4th October, in company with Dr. R. O. White and 
Mr. Langton of Messrs. Rusts, a visit was made to the Ancobra 
River mouth. e part examined extended about one mile from 
the beach, the water was tidal and distinctly brackish, there was a 
slow river current, and along both river banks a fringe of mangrove. 
Considerable numbers of rafts were lying in the river chained up to 
the mangrove and all logs examined were found to be attacked. 
On 7th October the mouth of Prince’s River was examined in 
company with the Mengel Mahogany Company’s representative 
stationed there. As in the case of the Ancobra the river was 
completely closed by a sand bar and there was consequently hardly 
any current. ere is an extensive mangrove formation extending 
at least a mile up river, and the water was decidedly brackish. Solid 
mahogany logs lying near the mouth of the river and which were 
stated to have been there at least two seasons were perfectly honey- 
combed and could easily be broken up by hand. Logs of Eriodendron 
anfractuosum lying in the water were also found to be attacked. 
Dead branches of shrubs lying in the river were all found bored, 
but with no recent traces of borers. 
‘On the 11th of October the Butre River was examined. This 
resembled the other rivers in being barred, in having a mangrove 
association in brackish water, and but little current. All logs lying 
in the river were found to be attacked. Some poles that had been 
washed into the river from a shipwreck, and which appeared to be 
of Scots Pine, were attacked similarly to native timber. 
The Butre River was examined above the mangrove association 
on 12th October; the water here was fresh, there was a fair current 
and there were no traces of worm-borers. 
Time did not permit for a visit to be paid to any other rivers, but 
a ey received from Half Assinie stated that no logs were observed 
ve been attacked by borers. It is necessary to state that at 
Half Assinie the T'ano River approaches to within two and a quarter 
miles of the coast and then turns westwards and does not communi- 
cate with the sea till some time after entering the French Ivory 
Coast. At the place referred to, therefore, there is a strong river 
current, fresh water, and no mangrove. 
After the visit to the Ancobra River a few experiments were 
attempted, but owing to the difficulty of extracting the borers from 
the logs, on account of the sinuous character of the burrows, they 
are not altogether reliable. The experiments, which were con- 
ducted on an open verandah near the sea and exposed to indirect 
sunlight, gave the following results. 
pure sea water turned brown within two hours of submersion, and in 
fifteen hours were in a high state of decomposition. Those immersed 
m pure rain water appeared to die within six hours and 
to decompose in fifteen hours. The control experiment in brackish 
