406 Mr. Gipron Manretu’s Description 
rence of form observable in these flints doubtless originated from 
the infiltration of a greater or less proportion of silex. Thus, had 
the Aleyonium, Fig. 1. been more contracted, and the siliceous 
matter in sufficient quantity to impregnate the whole mass and 
fll up the ventricular cavity, the flint would have resembled 
Fig. 1. and 4. of Tab. XXVII. In Fig. 2. at a are shown the ra- 
dicle processes passing from the base of the flint into the surround- 
ing chalk. 
Tas. XXIX. E: 
A chalk specimen exhibiting the disciform figure of the animal 
when completely expanded, and the reticulated structure of its 
external muscular coat. 
en 
‚Tab. XXX. 
A chalk specimen displaying the openings of the tubuli on the 
surface of the ventricular cavity, the animal being in a state of 
dilatation. 
Specimens in a state of contraction strikingly resemble in form 
the sponge figured in Ellis's Zoophytes, tab. lix. fig. 2: this, toge- 
ther with fig. 1 and 3 of the same plate, are described by Mr. 
Ellis as ** Sponges from Otaheite;" and it is a remarkable cir- 
cumstance, that the appearance of their external surface is very 
similar to that of the Alcyonium Chonoides. The discovery of more 
perfect specimens, either recent or fossil, may probably at some 
future period enable us to trace with uide success the relation 
they bear to each other. T. 
Although I dare not flatter ta yaelf. that the preceding observa- 
tions will add much to oryctological science, yet, as it is of the 
first importance that we should be extremely accurate in our refe- 
rence of fossils to their prototy pes, it is humbly presumed, that 
an attempt to prove the identity of specimens which had for- 
merly 
