AMPHIPODA. 
399 
Esq. — who is officially connected with the harbour — to have all the 
beacons or “ perches ” marking the channel of the river (which they do for 
about two miles at the upper part of the estuary) examined, and if they 
proved to he injured, to favour me with specimens of the damaged wood. 
All this he kindly had done in the month of May, 1847, when the beacons 
proved to have been all attacked, and those most under the influence of 
the fresh-water to have suffered equally with those nearest to the open 
sea. The ship-carpenter, who cut the damaged portions off that were 
sent me, stated to my friend that some old mooring-buoys so high up as 
the Old Long Bridge were found on removal injured in the same man- 
ner. The Limnoria was the only borer of any kind found in the beacons 
alluded to. 
It must be mentioned, that, judging from the superior size of the Che- 
lura borings to those of the Limnoria in Dublin Bay, I had from that 
circumstance noted down the perforations in pieces of oak and black birch 
washed ashore at Belfast as the work of the Limnoria ; but perceiving, 
on examination of the wood from Ardrossan, that the borings of the two 
species may not only be of equal size, but that those of the latter species 
may be the larger, I was taught that the presence of the excavator himself 
must be essential to settle the point, and that circumstantial evidence is 
insufficient. The wood in question had been so long tossed about in the 
sea that the animals were all washed out : — both pieces had also been 
bored by the Teredo norvegica (T. navalis , Turt.). 
In reference to the length of time that the Chelura will live after being 
removed from its native element, the following note was made. A few 
specimens taken from the sea on Monday morning and received by me in 
the afternoon of that day were alive on Thursday morning, or seventy- 
two hours afterwards, when, leaving home for England, I took the piece 
of wood containing them with me, and on examining it next day found 
them dead ; they had probably lived out of their native element about 
ninety hours. A number had lived in the same wood for about sixty-five 
hours; they were alive on Wednesday night at 12 o’clock, and dead on 
the next morning at 7 o’clock. The wood in which they were, was a 
small piece about six inches in length and an inch in thickness ; it was 
not wetted since being received on Monday, and was kept in a warm 
room (about 65° Fahrenheit) all the time. The apparently simple fact of 
the species thus living so long out of water has a very important bearing, 
for it suggests to us that this species could, like the Limnoria, commit its 
devastations in wood left dry by the ebbing of every tide. Dr. Cold- 
stream informs us that the latter species “ often effects a lodgment in 
piles very near high water-mark, where it is left dry by the receding 
tide during the greater part of every twenty-four hours,” and I have very 
little doubt that the Chelura could play a similar part. I have not heard 
that the extent of the damage done at Ardrossan by the destructive ani- 
mals noticed in this communication has yet been estimated, but on lately 
writing to my obliging friend and correspondent there, requesting him to 
procure if possible perfect specimens of the Xylophaga for dissection — the 
testaceous portions only had before been sent — he replied that the oppor- 
tunity for so doing was now past, “ as the damaged portions of the dock- 
gates had been replaced by sound timber.” 
