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CLASS STELLERIDA. 

 ORDER ASTEROIDEA. 

 Family PALJEASTERIDJE. 



PAL.EASTER WYKOFFI, n. Sp. 



Plate III, Fig. 27, ventral side. 



Species medium size. Rays petaliform; length about one and a 

 half times the diameter of the body; breadth of a ray at the place of 

 junction with the body, about two-thirds -the diameter of the body; 

 obtusely pointed. 



Marginal plates wider than long and numbering about fifteen in 

 the length of half an inch from the body. The marginal plates curve 

 regularly around the tips of the rays. The adambulacral range curves 

 around the ends of the rays within the marginal plates and consists 

 of subquadrate plates, wider than long. They are a little shorter 

 than the marginal plates, so that there are about eighteen in the 

 length of half an inch. There are ten oral plates at the junction of 

 the adambulacral rows which present triangular extensions toward 

 the center of the ventral cavity. A single, irregular, axillary plate 

 rests between the terminal marginal plates and the angle formed at 

 the junction of the adambulacral plates. The ambulacral plates have 

 their greatest length across the rays, thus providing a wide ambulac- 

 ral furrow. Each plate is furnished with a sharp ridge in the middle, 

 extending from the middle furrow to the adambulacral plates. 



Our specimen exposes only the ventral side and no spines are pre- 

 served, It is a well-marked and beautiful species. 



Found in the upper part of the Hudson River Group, near Madi* 

 son, Indiana, by Chas. W. Wykoff, in whose honor we have proposed 

 the specific name, and now in the collection of Win. F. E. Gurley. 



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Plate II, Fig. 30, summit; Fig. 31, side view; Fig. 32, under side. 



This is a spheroidal bulb, composed of nodose, sculptured plates. 

 The sculpturing makes them pyramidal, and, on the under side, 

 there is a pit at each angle, which may penetrate the bulb. The 

 plates are larger on the upper side than they are below. The lower 

 side may have attached to some other object at the large circular 

 aperture. If it ever attached to a crinoid, as part of the proboscis, we 



