CONTRIBUTIONS TO PALEONTOLOGY. 123 



Surface marked by strong indentations at each angle of the plates, 

 giving an elevated appearance to the space on the border of the 

 plate between the angles, forming ridges which join across the 

 sutures of the plates. Column long, proportionally strong, com- 

 posed of very unequal plates alternating with each other. 



Geological formation and locality. In the shales of the Hamilton group: 

 Ontario county. C, A. White, collector, 



CYATHOCRINUS (SUBGENUS?). 



CYATHOCRINUS BULBOSUS ( n. s.). / ^, - 



Body small, nearly hemispherical, forming a bulb-like projection at 

 the base of the strong expanded arms. Basal plates minute : sub- 

 radials of moderate size, four hexagonal, one heptagonal. First 

 radials larger than the subradials, broad, short, pentagonal. Anal 

 plate elongate, quadrangular. Arms spreading horizontally from 

 the body, proportionally strong and massive, composed of short 

 broad plates with outer margins slightly elevated. In some rays 

 the first bifurcation is upon the third plate, in others at greater 

 distances, and varying in difierent specimens : in one specimen, it 

 occurs on the eleventh plate of one ray. Above the first, there are 

 generally about three other bifurcations in the main division, and 

 the branches divide at irregular distances, giving ten to fifteen 

 branches to each ray. 



The terminal plates of the outer divisions are thin, and obtusely 

 pointed. The lateral diameter of the arm-plates is about double 

 that from the outer to the inner faces. Inner face of the arms 

 strongly grooved. The scars for the attachment of tentacula have 

 not been observed. 



The body is proportionally very small, the arms spreading an inch 

 and a half on each side. The column (if any) has been extreme- 

 ly small, as no cicatrix for its attachment has been observed. The 

 arms in all the specimens are expanded, and this appears to have 

 been the normal condition. 



The structure of the body, being identical with that of Cyathocrinus, 

 offers no means of separation from that genus; but the strong expanding 

 and broadly grooved arms are unlike any of its known species. 



Geological formation and locality. In the limestone of the Upper Hel- 

 derberg group : Livingston county, N.Y. 



