dd: Dr. T. Wright on new Species of Echinodermata 
extend into the mouth ; this opening is in the centre of the disc, 
and has a subpentagonal form; it is of a moderate size, and is 
surrounded by ten stout spines formed by the development of 
the first lateral plates, which are much expanded and terminate 
at the oral border in short stout spinous processes; the lateral 
plates from the adjoming rays are here united together, so that 
two spines from the lateral plates of different rays are closely 
approximated, and the five rays are thereby united together 
round the mouth-opening like five Gothic arches, so that the 
mouth with its channels, formed by these arches, resembles a 
miniature starfish in the centre of the disc; the five pairs of 
spines may have served as jaws. 
Affinities and differences.—Our knowledge of fossil Ophiuride 
is unfortunately so limited, and the details of those forms 
known are so meagre, that there is much difficulty in making 
a comparison between the extinct genera of this family. In our 
description of Ophioderma Gaveyi a diagnosis has been attempted 
between it and O. Milleri, Phil., both of these being Liasic spe- 
cies. The other forms hitherto published are those figured by 
Goldfuss, namely the Ophiura prisca, Miinster, from the Muschel- 
kalk of Baireuth; the Ophiura loricata, Goldf., from the Muschel- 
kalk of Wiirtemberg; the Ophiwra speciosa and O. carinata, 
Miinster, from the Lithographic slates of Solenhofen ; of these 
Goldfuss’s figures are excellent, and leave nothing to be desired, 
as that able natural-history artist Herr Hohe, whose crayon has 
added such lasting value to the ‘ Petrefacta Germaniz,’ has given 
accurate details of structure which prevent the possibility of con- 
fusion regarding the identification of the species drawn by him. 
The Ophiura Egertoni, Brod.*, found in nodules of micaceous 
sandstone at the base of the Inferior Oolite near Charmouth, is 
so entirely distinct from our fossil, that to mistake them is im- 
possible ; between O. Griesbachii and O. speciosa and O. carinata, 
the difference is likewise very great; O. loricata comes nearer to 
our Brittle-star than either of the others, but the great develop- 
ment of the lateral plates of the rays, and the clasping and im- 
bricated character of the same in O. Griesbachii, forms a struc- 
tural character which separates it widely from Goldfuss’s species. 
If we seek further for resemblances to our Brittle-star, we must 
look for them more amongst the beautiful Ophiocome of our 
seas than among any forms we are acquainted with in the fossil 
state, but even between it and them the differences are many and 
distinct. 
Locality and stratigraphical range——This beautiful fossil was 
collected by the Rev. A. W. Griesbach from the Forest marble of © 
* Geol. Trans. 2nd series, vol. v. pl. 12. 
