VENTRICULITES. 
97 
tion necessary to determine their specific characters. 
I have also very beautiful examples of a small Mil- 
lepora and retipora. 
The spongeous, inarticulated, porous zoophytes 
are by fiir the most abundant ; and, in fact, are so 
numerous, that scarcely a Hint is broken in which 
traces of their structure may not be detected. 
Many of these are decidedly branched sponges ; 
others approximate to the Alcyonia ; but those 
which in the “ Fossils of the South Downs” are 
referred to the new genus Ventriculites, have cha- 
racters so well defined, that notwithstanding some 
respectable writers have amused themselves with 
either giving them new names, or arranging them 
as s})ongiiu, alcyonia, &c., I shall still consider them 
as distinct ; and as they are among the most nu- 
merous and characteristic of the chalk zoophytes, 
a description with figures, is subjoined. 
y^entriculites A zoophyte of a funnel shape, 
having the base or stirps furnished with radical 
fibres or processes of attachment ; the external 
surface reticulated, the inner covered with mi- 
nute perforated papilla?. The original substance 
spongeous or gelatinous. The zoophyte capable 
of contraction and expansion ? The common 
species, V. radiahu<^ has the external integument 
formed of subcylindrical, anastomosing fibres, 
which radiate from the centre to the circum- 
ference : the papilla? on the inner surface are 
formed by the open extremities of short transverse 
tubuli. 
So numerous are the accidental varieties of form 
assumed by the fossil remains of this species, that 
u 
