
THE 
AMERICAN NATURALIST 

VoL. XXIV. JANUARY, 1890. 277. 

ON EXCAVATIONS MADE IN ROCKS BY 
SEA-URCHINS. 
BY J. WALTER FEWKES. 
HE cavities made by sea-urchins in solid rocks were first 
described at length by Mr. E. T. Bennett’ many years 
ago (1825), and since their discovery the phenomenon has been 
repeatedly mentioned and discussed. The habit is not confined 
to any single genus, and it seems capable of proof that the same 
species does not resort to this practice in all localities in which 
the animal occurs. 
The history of the different opinions in regard to the character 
of the excavations and the means and object of the boring have 
been considered by others. It is my purpose to barely refer to 
the historical part of the subject, or simply mention it without 
further comment. The question has both a geological and zoo- 
logical, and likewise a botanical side, as the aid of certain low 
genera of alge has been thought necessary to account for the 
phenomenon. 
Leske and Linnzus described a species of Cidaris, C. saxatilis, 
but it does not appear that either of them was familiar with the 
boring habit of sea-urchins. Rumphius mentions the fact that 
some sea-urchins are found in holes. Lamarck first gave a 
1 Notice of a Peculiar Property of a Species of Echinus. Trans. Linn. Soc., Vol. XV. 
P- 74, 7, 1826. 
