90 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



when the side-pieces are in situ, is totally filled, and the sides of the 

 ambulacrum rise abruptly above the abutting edges. The side-pieces 

 rest against the upper face of the deeply crenulated ridges of the 

 lancet-piece. They are strongly wedge-shaped and placed oblicjuely 

 to the aftnbulacral or food groove, with the smaller angle directed to 

 the ab-oral side. Their number is from about sixty to nearly ninety in 

 very large specimens. The outer side-pieces (sujjplementary pore- 

 pieces of Roemer) are comparatively large, their longer side being 

 about two-thirds, their shorter sides fully one-half, of the corresponding 

 sides in the jjore-pieces. 



The summit is a flat disc, somewhat depressed in the middle, sub- 

 pentangular in outline, the angles resting against the slightly truncated 

 upper part of the oral i)lates, leaving in the direction of each ambula- 

 crum a good-sized passage. The central aperture is pentangular, 

 rather deeply depressed. 



Spiracles ten, one to each side of the ambulacrum; those of the pos- 

 terior side not in contact with the anal aj^erture. They are in this 

 species not easily detected, being placed laterally within the projecting 

 edges of the interradials, which for their reception are at this place 

 more prominent, and somewhat excavated. The hydrospires are ar- 

 ranged in ten groups, with two in each group; they are in form similar 

 to those of Granatocrimis Norwoodi, but comparatively a little larger. 

 Hydrospire-pores small, and more or less hidden. 



Column of medium size, round, composed at the upper end of high 

 joints. 



The ornamentation of the radials consists of indistinct concentric 

 curves sub-i)arallel with the arched upper surface of the plate. The 

 ornamentadon of the interradials, as in most species of Eheacriniis, is 

 sharply divided by two longitudinal lines, the median part (which in 

 position and somewhat in form, at the four lateral sides of the body, 

 corresponds to the large anal plate of the posterior side) is more or 

 less destitute of ornament. The two sides, however, are crowded with 

 rows of small granules, arranged so as to divide the field into narrow 

 parallel spaces, which are transversely arranged, and of the width of 

 the i)ore-pieces. 



Observations : Elteacriniis obovatus differs from Eheacriniis ( Niicleo- 

 crinus) annularis Lyon in the greater length of the body, and in hav- 

 ing straight and not concave sides. It resembles, perhaps, closest 

 Elicacrinus ( Nitcleocritiiis) lucijia Hall, and may be identical with the 

 larger form noticed in the same paper, and which Hall considered a 



