L. Agassiz on the Echinodermata. 445 



0. Pentacrinus, Mill. (Pentagonites, Raffin.) — Pedicel more or 

 less pentagonal, bearing at intervals simple verticillate rays ; rays of 

 the disc fixed to the pedicel, each by a cuneiform piece followed by 

 two simple pieces, after which the rays bifurcate, and at a little 

 further distance divide into two, which then branch out into nume- 

 rous appendices, pinnate at their edges. The space between the base 

 of the rays, occupied by the visceral cavity, is formed by numerous 

 small lamina?. One living species and several fossil species from the 

 muschelkalk, cretaceous, Jurassic, and tertiary, deposits. 



Those species in which the accessory rays form more or less distant 

 verticillae might be designated under the name of Chladocrinus. 



P. dubius, Goldf. — P. basaltiformis, Mill. — P. briareus, Mill. — P. cingu- 

 latus, Munst. — P. muliferus, Munst. (not Mill.) — P. annulatus, Rcem. — 

 P. pentagonalis, Gold. — P. Icevis, Mill. — P. scalaris, Goldf. — P. subangu- 

 laris, Mill. — P. scriptus, Roem. — P. subsulcatus, Munst. — P. subteres t 

 Munst. — P. tuberculatiis, Mill. — P. moniliformis, Mill, (not Munst.) — P. 

 subbasaltiformis, Mill. — P. caput Medusa?, Mill. 



10. Isocrinus, N. de Meyer. — Nearly allied to Pentacrinus, of 

 which it has the pedicel with its simple rays. The first articulations 

 of the rays of the disc are not prominent as in that genus ; the upper 

 portion of the pedicel however is more developed. One fossil species 

 from the jura. 



/. pendulus, N. de M. (hitherto inedit.) 



11. Encrinus, Guett. — Pedicel rounded and smooth ; rays of the 

 disc formed at their base of three simple consecutive joints, to the last 

 of which are articulated two series of smaller pieces, each bearing at 

 some further distance from the centre, two series of pinnate articula- 

 tions moveable on their hinges. All the species are fossils from the 

 muschelkalk. 



E. Uliiformis, auct. — E. Schlotheimii, Quenst. 



12. Apiocrinus, Mill. (Astropoda, Defr. — Ceriocrinus, Keen. — 

 Pomatocrinus and Symphytocrinus, Keen.) — Pedicel rounded and 

 smooth, dilating insensibly towards the base of the rays, which are 

 composed first of the three simple consecutive articulations alter- 

 nating with five distinct pieces from the summit of the pedicel ; at 

 some further distance each ray bifurcates and again subdivides into 

 lateral pinnulae. These animals are fixed to the soil by a dilatation 

 more or less considerable of the base of the pedicel. All the species 

 are fossil from the jura and chalk. 



A. elongatus, Mill. — A. flexuosus, Goldf. — A. incrassatus, Roem. — A. 

 mespiliformis, Schlot. — A. Milleri, Schlot. — A. obconicus, Goldf. — A. Pratii, 

 Gr. — A. rosaceus, Schlot.— A. rotundas, Mill. — A. ellipticus, Mill. 



