CONDYLURA CRTSTATA. 
5 I 
to arrive at any positive knowledge of the way in which they are 
made. All that one sees during their formation in dry soil is the 
upheaval of a quantity of loose earth from a central point, which 
point speedily becomes indistinguishable as the mound increases 
in size, the only observable phenomenon consisting in a little heap 
of dirt every particle of which seems to be in motion, as it steadily 
approaches completion. The rapidity with which so much earth 
is thrown up is one of the most perplexing things about it ; and 
the peculiar motion of the mass leads to the notion that it is 
traversed by galleries and that the Mole is at work within it and 
not beneath the surrounding ground. On making a section of the 
mound, however, it is found to contain no cavity unless it be a 
mere tubular extension of the gallery, and this is absent in more 
than half the hills examined. On opening the gallery beneath, no 
chamber or tortuous excavation is discovered, and the fact at once 
becomes apparent that so much earth as constitutes the hill could 
not possibly have been obtained from the excavation in its imme- 
diate vicinity, and must therefore have been brought from a dis- 
tance. Just how it was conveyed to and forced through the orifice 
leading into the hill I have until recently been at a loss to com- 
prehend, but the opportunity to examine some freshly made mounds 
in a wet pasture of rich loam or mould has cleared up the mystery. 
These new mounds consisted wholly of compact cylindrical 
masses of damp earth, having very much the appearance of Bologna 
sausages, and measuring from three to five inches in length by one 
and a half to two in diameter. It was noticeable that the size of 
each was greater than that of the hole in the sod through which it 
had been discharged, which circumstance shows that it must have 
been subjected to considerable pressure during expulsion. On 
handling these masses they readily broke up, transversely, into a 
number of more or less parallel discs, or lamellae, each of which 
bore evidence of having been powerfully compressed. On exposure 
to the air they soon lost their cylindrical form and crumbled, so that 
