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0 



Family TAxJcKINIDiE. 



FORBESOCRINUS PYRIFORMIS, n. sp. 



Plate fV, Fig. 1, view of an almost entire specimen. 



General form of the calyx and arms, together, suboyate or 

 somewhat pear-shaped, which suggested the specific name. The 

 column is round, large and tapers rapidly from the calyx, where 

 it is composed of very thin plates. 



The calyx constitutes more than half the length of the body 

 it is wider than high and somewhat obconoidal or funnel- 

 shaped above the column. The plates are convex. The inter- 

 radial areas are long and narrow, slightly flattened and de- 

 pressed below the radial series, which are gently rounded. 



Basal plates not observed. Subradials rather small. Primary 

 radials twice as wide as high, convex on the outer face, pentag- 

 onal, hexagonal, or hept agonal, depending upon the number of 

 interradials that abut upon them laterally ; four in each of four 

 series and only three in one of the lateral series; concave on 

 the upper sides, immediately below which, they are most pro- 

 tuberant. The upper plates slightly overlap the next lower 

 ones, in the middle part, though not by a little toothlike pro- 

 jection, as in Forbesocrinus agassizi. This projection is de- 

 scribed as a distinct plate and called a "small patelloid plate," 

 by Hall, in the Geological Eeport of Iowa, vol. 1, p t. 2, p. 631, 

 and we find that error, in respect to F. agassizi, transferred to 

 the definition of the genus, in the "Kevision of the Palaeocrino- 

 idea," by Wachsmuth & Springer, page 51, where they say 

 "The sutures of the radial and arm plates strongly sinuate, 

 and partly occupied by additional patelloid plates." The tooth- 

 like projection, in Forbesocrinus agassizi, is not a separate 

 plate; there are no patelloid plates in any species of Forbeso- 

 crinus, and it is not too much to say, they have no existence, 



