THE GEOLOGIST. 
13 
The species at present known are, Woodocriuus macrodactylus 
— the tyiie species — W. expaiisus, W. goniodactylus, W. decodac- 
tylus, and two others. There are imperfect remains of other 
species, and also of another new genus, but the specimens yet 
found are too imperfect to pennit us to form a satisfactory opinion 
about them. 
Of all the species Woodocrinus macrodactylus is by far the 
most common ; not more than three or four good specimens of the 
others having been found among the accumulated debris of the 
type species. 
The genus, which has been named after Mr. E. Wood, of Rich- 
mond, the discoverer of the whole series, is related to the genus 
Cyathocrinus of MUler, Taxocrinus of Phillips, Forbesocrinus of 
De Koninck — differing in having five subradial plates ; while the 
first has only four, and the second and third none. It appears also 
to differ from Cyathocrinus in the mode by which the second radial 
is attached to the first radial plate, and from the two last in having 
the radial joints free, instead of being united laterally by inter- 
radial plates. The calix or head of this genus is cup-like; 
generally widely opened except in Woodocrinus decodactylus, 
which is naiTow and elongated, like a champagne glass. 
Woodocrinus expansus slightly differs fi'om the others in having 
the shelly plates which form the cup, larger and thicker. 
Like all other Crinoides, the calix is composed of a series of 
plates, which in this genus are quite smooth, and form themselves 
into a star of five rays ; the base contains five plates. Alternating 
with these are five large hexagonal plates, called ' sub-radial ;' 
which in their turn alternate with five pentagonal plates, called 
'radial;' superposed upon which are five more radial plates, 
which are axillary, and from which spring two arms, which 
bifurcate fi-om one to four times, according to the species. The 
basal and sub-radial plates are united by their lateral edges. The 
radial plates and aims are free. 
In Woodocrinus macrodactylus the arms bifurcate but once, and 
are 20 in number ; they are thick, cyliadrical, and in appearance 
not unlike the common earth-worm. In W. decodactylus they 
are long and slender, and bifurcate twice, making the number of 
rays 50. In W. expansus they bifurcate three or four times, and 
