PENTREMITES PYRIFORMIS. 297 
Ruopocrinus (f. verus. Pict. Atlas, pl. xlix. fig. 7, 8.).— 
_ A beautiful form, allied to the Antinocrinoids, occurs in the 
_ paleeozoic rocks, and is named the Rose-encrinite by Miller. 
The column is cylindrical and traversed by a pentagonal 
canal. The rays or arms arise by a single ossicle and then 
 bifurcate : the receptacle is formed of three, five, ten, and 
more numerous series of plates, which are ornamented 
externally. A fine example of a crinoid of this type (Hypan- 
thocrinus) from the Wenlock limestone, is figured in the 
London Paleontological Journal, pl. xxi. 
In Sir R. Murchison’s Sil. Syst. all the crinoids of the 
Silurian deposits, then known, are figured. Several new 
genera are described by Professor McCoy, in the Synopsis 
of British Palzeozoic Fossils. 
EuGeniacrinus (Clove-like Enerinite). Lign. 92, fig. 1. 
_—These little crinoids, which resemble a clove in form, are 
found at Mount Randen, in Switzerland, in Oolitic limestone. 
The receptacle is simple in structure, for it has but one 
series of plates ; its cavity is very small. It had five arms: 
the articulating surface of the ossicles is radiated. When 
perfect this crinoidean must have somewhat resembled the 
Lily Encrinite, but the plates are all anchylosed, or blended 
together, which Mr. Miller attributed to an early stage of 
growth. 
PENTREMITES PYRIFORMIS (Pear-shaped angular Encrinite). 
Lign. 91, fig. 2.—The column of this remarkable crinoid is 
short, and formed of cylindrical, perforated ossicula, with 
radiated surfaces, and has irregular side-arms. The recep- 
tacle is composed of polygonal plates, divided by five perfo- 
_ rated grooves or furrows, which are of an elongated petalous 
form, and converge in a rosette on the summit. The mar- 
ginal longitudinal rows of minute pores are not however for 
the passage of soft membranous feelers, as in the ambulacra 
of echinoderms, as was formerly conjectured, but are channels 
