262 



posterior end is conical and gaping behind. A crenulated 

 ventral margin; a straight cardinal line; prominent and 

 strongly-incurved beaks; prominent nmbonal ridge, orna- 

 mented with an expansion of the test in continuation of 

 the truncated anterior end; external ligament: concentric 

 stria> and strong radii.— are characteristic features of this 



genus. 



Conocardium normale. Hall. (Pig. 181.) (Pal. N. Y., 



Vol. VII.. p. 41^ 

 PL LXVIII.) 



D is t in g u ishing 

 ( naracters. — Large 

 size; trigonal out- 

 line; tapering pos- 

 terior end ; short, 

 distant radii, with 

 fine stri;e in the 

 interspaces ; concentric, undulating stria?. 



Found in the Encrinal limestone, at Section .*> la frag- 

 ment). 



Conocardium eboraceum. Hall. (Fig. 182.) (Pal.N.Y., 

 Vol. VII., p. 412, PI. LXVIII.) 



Distinguishing Characters.— Small size, sub-ovate outline; 

 gently curving basal margin; slightly concave truncated 



Fig. 181. Conocardium normale. 

 large specimen (from Hall). 



The left side of a 



^i/ IG '. 182- a £ onoc( ? I rd ,» lm eboraceum. Right and ventral views of a small specimen 

 enlarged, x 2 (from Hall). ^ 



end; abruptly -contracted and nasute tapering end; con- 

 centric lamellose striae, and radiating plications, obscure on 

 the perfect test; radii continued bevond the concentric 

 laminae at the margin as strong interlocking denticulations. 



