loG 
vine: notes on britisfi eocene polyzoa. 
Flustra crassa, Desm. London Clay, Highgate, p. 14. 
Polyzoon Sydenham, p. 14. 
In my British Association Report on Fossil Polyzoa (1884-5), 
and also in the supplementary part of the Report on Recent Polyzoa" 
(1885-6), I referred to, and gave all that was known of the Fossil species, 
and a full reference, as far as I was able to at the time, of foreign 
horizons of Eocene and Miocene Polyzoa. 
When compiling material for the Tertiary division of my British 
Association Report on Fossil Polyzoa (oth of the series), relying 
upon a general experience of the subject, I naturally suggested that 
the poverty of a British Eocene Polyzja fauna may be ascribed to 
want of research rather than to a positive absence of forms. My 
suggestion was futile, and I have learned since that Eocene Polyzoa 
is indeed scarce, both in this country and on the continent. My 
friend, ^Ir. Bell, writing me on the subject, goes into the question 
rather fully, and as there is a scientific value in his remarks I cannot 
forbear quoting and endorsing his views. 
" Considering the richness of other sections of organic life in the 
Eocene, the great poverty of the ^lolluscoida : Brachiopoda and Poly- 
zoa, is very remarkable, and this poverty does not arise from an 
oversight on the part of collectors, or for want of looking for. 
Some thousands of specimens having passed through the hands of 
one or other of us, it is possible to speak with some amount of cea*- 
tainty upon this head. Of the few species listed, 31. Lacroixii, Flus- 
tra crassa, and Lunulites xirceolatus, are the commonest, but are by 
no means abundant ; and the first two have a wide range in Eocene 
time. Xeither do they occur in any quantity in the Continental 
Eocene fauna, as an examination of some thousands of shells from 
the Paris basin will expose an equal sparseness. 
The cause of this absence is difficult to explain, as far as tlie 
free-gTowing Cyclostomata are concerned, unless that the soil, or food, 
or other conditions of life, was not favourable for their development. 
For the adnate Cheilostomata, the want of such shells or adherent 
surfaces proper for their habitat may be sufficient cause. 
Reasoning from the rich Crag fauna, it would appear that Polyzoa 
