38 
The Acicul^e capitatce, in their respective varieties of forms and 
colours, are found chiefly belonging to the echini of the genus miliaris 
and variolata. 
Instances of their preservation, in a petrified state, have not been 
frequently mentioned. Two unconnected specimens are figured by 
Volkmann, Sites. Suht. Tab. xxx. Fig. Vj , 18; and it is this species 
of which Gesner speaks, cle Petrijicat. p. 36 d. as aculei, s. radioli 
leves, exquisite cuspidati. Two specimens are also figured by Muller, 
Delic. Natur. Tab. d. i. Fig. 1, 5. But no instances are given, in 
any author, of their preservation in a fossil state, in connection with 
their shell. In the specimen in chalk, Plate I. Fig. 10, one of these 
spines, of a subulated form and striated surface, is seen in that situa- 
tion, which gives full reason to suppose its relationship to the shell 
■which it accompanies. The flint specimen, Plate III. Fig. 1, is in- 
teresting, from its showing that E. saocatilis is provided with spines 
of a similar shape : in one part the spines are seen, with their articu- 
lating terminations, lying close to the points to which they belonged ; 
and in another, one of the spines is seen in the substance of the flint, 
still attached to the shell. In the remarkably fine specimen from 
Stunsfield, in Oxfordshire, Tab. I. Fig. 8, some little variation is ob- 
servable with respect to the spines. Like the former, they are striated, 
subulated, and rather bent ; but they gradually, though very slightly, 
swell a little about their middle, and thence become somewhat fusiform. 
In the flint fossil, Plate I. Fig. 5, which was considered as one of 
the most valuable in the Leverian Museum, spines of this class are 
still seen adherent to the echinital crust, and imbedded and passing 
into the solid flint. These are subulated like the preceding, but are 
more straight. The echinite of this specimen appears to be of the 
variolated kind. 
In the interesting specimen of Cidaris papillata, from Caine, PL I\ . 
Fig. 20, spines of the same class are fixed. But these appear to have 
been longer, and more of a cylindrical form than those above described. 
