MACKIE — ON THE B0TT0M-R0CK8. 
187 
abraded before they were covered up and entombed ; the sun-crack 
shows the drying influences of the wind and sun ; while in the hollow 
Lign. 2. — Sea-Ripples. The arrow indicates the direction of the wind. 
spaces where the moisture was retained, the worms perforated by 
scores the damp earth. 
" We may live," says Mr. Binuey, " among the grandest scenes of 
nature, or may visit the noblest monuments of art, and remain in- 
sensible to their beauty or sublimity. Differently affected, we may 
find in the barren sands of the sea-shore enjoyment of the purest 
character, and speculations which, rising from nothing more impoi-tant 
than the trail of a sea-slug, will lead us to contemplate, and in some 
measm'e to comprehend, some of the most extensive operations of 
nature, and bring under review unnumbered ages, past, present, and 
to come." 
The Arenicolse construct no tubes on the suiface of marine objects, 
they have no protecting cases nor shells, no solid skeletons, but their 
soft, ring-formed bodies, supporting on each segment tufts of bristle- 
feet, and featheiy, vein-like, external lungs, lie buried in the sand, and 
there, by means of their terminal retractile proboscis, unai'med by 
teeth, these sightless beings suck in the watery sand, or ooze, and 
obtain their nutriment in the organic particles it contains. Dying, 
they leave nought but their burrows and their trails ; of themselves, 
nothing. 
These old fossil worm-holes of the Longmynds are much smaller 
than the recent ones of the common Arenicola piseatorum ; and in all 
cases that I have seen, there is in them an absence of those coils of 
sands at the vent-ends of the bun'ows, and of the conical cavities at 
the other extremities, which, everywhere on our sea-sands and shores, 
mark the existence below of the innumerable thousands of the fisher- 
