14 



THE GEOLOGIST. 



the rays reach the number of 80, or sometimes 100. These rays 

 are long, and veiy elegant; and the jomts have a wedge-like form, 

 and are so aiTanged that the thick end of the one corresponds 

 with the thin end of the next. In W. goniodactjlus the arms 

 bifui'cate so as to make a total of 50, while the joints differ from 

 those of all other species in the angular formation of their dorsal 

 aspect — the zigzag pattern fonned by their peculiar style of 

 articulations — and the thickening of the last axillaiy joint of each 

 ray. The number of joints in each ray is never less than 4, and 

 never more than 10. Each joint of these rays is furnished with a 

 long, slender, many-jomted, flexible pinnule, which spiiags 

 alternately from opposite sides of the arm, so as to make two 

 rows. In W. goniodactylus these pinnules are more delicate than 

 in the other species. The anal region, which is that part of the 

 cal)^ not covered by the radial plates, is composed of small 

 diversely-formed pieces ; which are united above to the dome, and 

 laterally to those plates from which the arms spring. In W. 

 expansus these plates are fewer in number, and lai'ger than in W. 

 macrodactylus. The dome, which is the upper part of the 

 skeleton, has not yet been found entire in this genus. A few 

 plates of hexagonal and pentagonal form have been noticed ; but 

 neither its form nor size can be indicated with any certainty. It 

 appeal's to be large ; the plates are beautifully marked in a relief, 

 with a stai*-hke projection, not unlike the dog-tooth ornament 

 which characterizes early English architecture. 



The stems are composed of thin cylindrical joints, alternately 

 larger and smaller, gi\ing them a ring-like appearance. The thick- 

 ness does not differ much in any of the species. The length is 

 considerable, and very variable. But the special character of this 

 stem is that, luilike the stem of all known crinoides, it is much 

 thinner at the base than at the sununit. No actual termina- 

 tion can be said to have been discovered; but in all the species 

 the stem is invariahly tapering, so that the longer it is the thinner 

 it becomes. This circumstance would lead us to imagine, that the 

 creature floated freely m the water, and that the stems were used 

 to balance it, and keep it upright while it floated. Should this fact 

 be estabUshed, it will place this genus as a link between the free 

 Comatida and the fixed Crinoid, It may, however, have had the 



