FOSSILS OF THE BURLINGTON GROUP. 467 



CODOKITES GKACILS, M and W. 



PI. 8, Fig 6. 



BODY comparatively rather small, peiitagonal-suboval, 

 longer than wide, the widest part being at the lower ex- 

 tremities of the so-called pseudo-ambulacral fields, which 

 terminate a little below the middle. Supplementary base 

 small, very short, or only appearing to be composed of a 

 single tripartite joint of the column. Base low, or near 

 three times as wide as high, expanding rapidly upward, 

 and pentagonal as seen from below; basal pieces of mod- 

 erate size, two pentagonal and one hexagonal. Badial 

 pieces nearly twice as long as wide, with a general ob- 

 long outline, though they are a little wider in the mid- 

 dle than above or below, while the superior lateral angles 

 are a little truncated by the anal and interradial pieces, 

 and the lower end is either obtusely angular in the middle 

 or somewhat rounded; all rather distinctly convex below 

 the middle ; so-called pseudo-ambulacral sinuses rather nar- 

 row and slightly tapering, extending down a little below 

 the middle, where they each terminate at a little pointed 

 projection directed out horizontally, so as to add to the 

 pentagonal form of the body, as seen from above and below. 

 Anal piece of moderate size, wider and more obtuse below 

 than the interradials, and narrow above, with a compara- 

 tively large anal opening, nearly dividing it a little below 

 the narrowest part. Interradials more than twice as long as 

 wide, the widest part being below, while the central region 

 is much contracted, and the upper somewhat dart-shaped, 

 and, like that of the anal piece, in each a little concave, 

 with a small tubercle occupying the middle of the concavity. 

 So-called pseudo-ambulacral fields rather narrow; some- 

 what convex, with a mesial or ambulacra! furrow rather 

 wide and deep, particularly above the middle; pore or arm 

 pieces about twenty-two on each side of each area. Lancet 

 pieces very narrow, but thick, and rather deeply furrowed 



