NIAGARA GROUP. 207 



Genus EUC AL YPTOCRINUS. 



Eucalyptocrinites, Goldfuss, 1826. 

 ffypanthocrinites, Phillips, 1839. 



The Genus Eucai-yptocrinites is described by Goldfuss as having no cohimn, although in 

 his figures the arrangement of the plates clearly indicates the existence of this part of the 

 structure. In other respects there is no sufficient character to separate it from the Genus 

 Hypanthocrinites, established by Prof. Phillips. 



The structure of this crinoid is too peculiar to be mistaken for one moment ; and it can not 

 be supposed, from the evidence before us, that there is any ground for the foundation of a 

 distinct genus. 



596. 1. EUCALYPTOCRINUS DECORUS. 



Pl. XLVII. Figs. 1, 2 a- A, 3 a- d. 



Hypanthocrinites decorus. Phillips : Murchison, Sil. System, 1839, pag. 672, pl. 17, fig. 3. 

 — — Hall, Geol. Rep. 4th Dist. New- York, 1843, pag. 113, figs. 2 and 3. 



Compare //. ccelatus. Id. pag. 113, fig. 1 ; and pl. 47 ut sup. fig. 4 a. 



Column round, composed of alternating thicker and thinner joints, the thicker joints wider 

 than the thinner, with rounded edges ; two or three thin joints between each two of the thick 

 ones ; articulating surfaces of the joints marked by short, simple, and deeply impressed striae 

 reaching from the margin nearly to the canal ; canal distinctly pentapetalous, usually filled 

 with crystalline matter ; body subcylindrical or ovoid, gradually enlarging from the base up- 

 ward to the commencement of the arms, from which it gradually contracts to the summit, to 

 which the parts all converge, and are surmounted by a short proboscis. Pelvis composed of 

 five hexagonal plates, succeeded in a direct line by the same number of quadrangular costal 

 plates and pentagonal scapular plates ; each scapular plate supporting upon its oblique upper 

 sides, a pair of arm-joints ; arm-joints ten, pentagonal or hexagonal, each supporting a qua- 

 drangular hand-joint, which again supports a pair of fingers ; fingers in the lower part composed 

 of a single series of plates, but becoming divided above the fifth or sixth plate, and consisting 

 of a double series of alternating joints ; fingers tentaculated ; tentacula usually anchylosed 

 with the joints of the fingers and among themselves, forming altogether a solid thin cuneiform 

 plate reaching to the alimentary canal in the centre. 



In addition to this structure, there are five large intercostal plates having a cuneate base, and 

 resting upon the oblique upper edges of each two adjoining pelvic plates, separating the costal 

 and scapular plates, and having a short side of one arm-plate of each pair resting on its sloping 

 upper edges ; its two upper short sides support a pair of narrow elongated pentagonal plates, 

 which are placed in conjunction on their longest sides, separating the pairs of arms and fingers 

 at their base ; the union of these plates leaves, at their upper extremity, an angular depression, 

 from which proceeds an elongated solid plate or rib reaching to the summit, separating the 



