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Proceedings of the Royal Society 
in wet sand was kept open till, by gentle infiltration, the hollow 
was filled, and ah exact likeness of the interior of the tunnel 
realised on the infiltrated matter ! A very good example of 
the forms figured by Mr Hancock occurs on one of the slabs on 
the table. 
At a meeting of the Dublin Geological Society in 1858, Professor 
Haugbton, the president, read a paper “ On the Occurrence of some 
New and Hare Forms of Annelidoid Tracks in the Coal Measures, 
Lugacurren, Queen’s County.”* A year later, and again in 1860, 
he returned to the subject, indicating his belief that the Lugacurren 
tracks resembled those described by Mr Hancock, and ultimately 
accepting his theory of their crustacean origin. As Professor 
Haughton’s papers were illustrated by lithographic plates ad 
naturam , they, like Mr Hancock’s, are available for comparison 
with the specimen before us. The Lugacurren specimens differ 
from the Northumberland forms in having at one part four, in one 
case, and in another five circular depressions in the median line. 
They differ from that on the table in having circular depressions 
confined to a small part of the form, and a median groove, instead 
of, as here, oval depressions running the whole length of the body, 
and a median ridge. In neither the English nor the Irish speci- 
mens is the characteristic striation so conspicuous as in this. These, 
however, seem all to be specimens of closely related species. Both 
Mr Hancock and Professor Haughton think that the depressions 
in the median groove may have been made by the pygidium 
of a carboniferous trilobite, the print of the tail being the only 
trace the animal has left of its having had a place in this 
deposit ! Now such marks as those on the Lugacurren specimens 
could only have been made by the pygidium being set down ver- 
tically, then lifted for a time, and so placed at regular intervals, 
their being no evidence of dragging, — most unlikely, if not im- 
possible conditions. Fortunately, a good representation of the 
form figured by Professor Haughton occurs also on these slabs. 
From this it is evident that the characteristic circular punctures 
run the whole length of the body. 
It seems to me that the reference to the track of Sulcator arena- 
rius has been misleading. It can, indeed, have no bearing on any 
* Journal of the Geological Society of Dublin, vol. viii. 1857-1860. 
