204 
DESCRIPTION . OF THE FOSSILS. 
on age and other circumstances are not understood. Besides the species 
noticed in the following classification, Mr. Gilbertson possesses others 
and is likely to discover more ; his collection is also very rich in 
varieties and malformations; and I hope that he may hereafter he in- 
duced to give to the world the result of his very diligent study of 
these beautiful fossils. 
Platycrinus. — T ins genus is, I believe, in England, confined to 
the mountain limestone series. 
P. lands? Miller, PI. TII. fig. 14, 15. Bolland ; Bristol. 
Pelvis saucer-shapecl ; surface smooth. It is very doubtful whether this be really 
the species of Miller: the articulations of the scapulae do not quite agree. 
P. microstylus. Ph. Bolland. 
Surface smooth ; pelvis larger and more conical than in the last ; columnar ad- 
herence very small. 
P. granulatus. Miller, PI. III. fig. 16. Bolland ; Mendip. 
Scapular articulations small and marginal. 
P. tuberculatus, Miller, PI. III. fig. 17. Bolland ; Mendip. 
Truncato-cylindrical ; plates tuberculated in rows ; sutures sulcated ; scapular 
articulation large and low. 
- P. rugosus. Miller, PI. III. fig. 20. Whitewell in Bolland ; Caldy 
Island ; Mendip. 
Pelvis and scapular plates rudely massive ; scapular articulations large and low. 
P. ellipticus. Ph. PI. III. fig. 19, 21. Alport in Derbyshire ; Bolland. 
The interscapular plate not so long as in others. Plates radiato-tuberculate, with 
raised borders and sulcated sutures. 
P. laciniatus. Gilb. PI. III. fig. 18. Bolland. 
Very like the last ; plates tuberculato-laciniate at their edges ; scapular articula- 
tions small and marginal ; columnar adherence prominent. 
P. gigas. Gilb PI. III. fig. 22 , 23- Bolland. 
Proboscis elevated, central ; pelvis broad ; scapula: broad ; interscapulars very 
unequal. It grows much larger. 
P. elongatus. Gilb. PI. III. fig. 24, 26. Bolland. 
Pelvis conical ; scapulae much elongated. The specimen has an interscapular plate 
attached to the pelvis. 
P. contractus. Gilb PI. III. fig. 25. Bolland. 
Pelvis tapering, acute ; scapulae narrowing above ; column very slender. 
