A MONOGRAPH 
ON THE 
BRITISH FOSSIL SPONGES. 
INTRODUCTION. 
TaoucH Fossil Sponges are mentioned in some of the earliest works in which 
fossils are treated of, and descriptions of them appear in nearly all subsequent works 
on palxontology, their true characters, until a comparatively recent date, were 
completely misunderstood, and their history was a mass of hopeless confusion. In 
the absence of any clear ideas as to the real nature of these organisms, the most 
heterogeneous materials were relegated to the group, and indeed it might be said to 
have been the practice—not altogether obsolete even now—to regard as a Sponge 
any fossil whose structure was too obscure to be satisfactorily placed elsewhere. 
One of the principal reasons for the chaos which existed was the erroneous idea, 
enunciated more particularly by D’Orbigny and Fromentel, that fossil Sponges 
belonged to an entirely extinct group, of a different nature to those now living, and 
consequently that no clue could be obtained to their original structures by a 
comparison with those of living forms. 
Acting on this mistaken idea, those who studied the fossil forms did not attempt 
to carry out a systematic investigation of their skeletal structures, like that which 
had been so successfully apphed to existing Sponges, but they were content to limit 
their investigations to the external form and the superficial canal structures, 
features possessed in common by many Sponges whose skeletal characters are 
essentially diverse. The classification thus based, was for the most part valueless 
and misleading. Here and there observers were not wanting who noticed the 
importance of the skeletal structures of these fossils, and amongst these Etallon 
deserves special mention ; but no thorough attempt was made to apply the principle 
of the character of the skeleton, as the basis of classification, until that successfully 
carried out by Professor Zittel im 1877-78. Since the publication of Zittel’s 
A 
