628 
ZOOLOGICAL LITERATURE. 
Museum of Natural History. This is followed by a general 
summary of the author^s view9, ending with an historical survey 
of the whole subject, which, however, is by no means complete, 
allusion being made to the writings of only one British natural- 
ist. Finally the author suggests the palseontological application 
of his studies, and refers to a block of oolitic limestone in which 
obscure perforations of an Echinus have been observed. 
1. Echinus Iwidus is found in perforations of characteristic aspect at various 
stations on the Atlantic coasts of Ireland, France, and Spain, also on the 
shores of the Gulf of Lyons. 
2. These holes occur in rocks which vary much as to hardness and miue- 
ralogical composition — limestone, sandstone, and granite. 
3. The holes always contain water, even when situated between tide-marks. 
4. The holes are regularly disposed in groups of from twenty-five to a 
hundred. They are so close together as to leave no room for the formation 
of other perforations between them. (Fischer, p. 322.) 
6. The holes never communicate internally with one another^ however they 
may approximate or appear indistinqt at their margins. 
6. Incrustations of calcareous Algce usually cover the margins of the holes 
and tho spaces between them. The nearer the holes the larger fhese laminie 
of Nullipores, which are always smooth, whereas when they occur apart 
from the holes their surface is much broken and presents a coralline aspect. 
(Fischer, p. 323.) 
7. Minute fragments of shells, mixed with loose sand, may be found within 
the holes. When these are removed, the naked rock appears, — the interior of 
the perforations, save when abandoned by the Echini^ being (juite free from 
adventitious growths. 
8. The holes vary in size. Bach s exactly fitted to its inhabitant, sufiicient 
space l^ejng left for the action of its spines. 
9. In depth, each hole varies from about two to four centimetres, but in 
some specimens reaches ten centimetres. These deep holes are cylindrical. 
The ordinary holes are hemispherical. (Fischer, p. 322.) 
10. Each hole contains but one Echinus, This invariably occupies the 
same position, its mouth resting on the centre of the base of the hole, 
which exhibits a con’esponding impression. 
XI, In districts where the holes occur, the Echini are never found in any 
ether situations. They never (]^ult the water, or, so far as has been observed, 
their holes. IIow they feed is not known, 
12. On sandy coasts Echinus lividus does not perforate j on some rocky 
coasts it simply takes up its abode in chance cavities. Perforation, therefore, 
seems to be determined, under certain conditions, by the vital necessities of 
the animal. Examples of Mollusks might be cited in which a like diversity 
of habit presents itself. (Fischer, p. 326.) 
13. Seeing that these holes occur in rocks which differ widely in nature, 
their production may well be assigned to one and the same agency. The 
hypothesis of a chemical solvent is, for the same reason, not tenable. 
14. X'hat the Echini perforate the holes in which they occur, seems proved 
