INVERTEBRATES. 79 



irregularly distributed over the whole surface; cup nearly cir- 

 cular, moderately profound: fossette large and situated on the 

 side of greatest curvature: lamella? about forty-four, those on 

 either side of the fossette to the number of about ten coalescing 

 before reaching the center of the cup. 



This species may be distinguished from the large allied forms 

 by tin. 1 size and position of the septal fossette. 



Height.. 1/ 1( , inches; breadth of cup, 1% inches. 



Position and locality: Warsaw division of the St. Louis 

 group, near Columbia, Monroe Co., 111. 



Collector, A. H. Worthen. 



No. 2567 of the Illinois State Museum. 



ZAPHREXTIS PARASITIC A. (sp. nov.) 



PL X, Figs. 5-5a. 



Corallum small, truncated at the lower extremity, slightly 

 expanded and compressed: breadth of the calice a little more 

 than the length: surface marked with strong longitudinal 

 striae: septal fossette comparatively large, central, extending 

 laterally on the side of greatest curvature; about twenty strong 

 lamella? extend from the border to the central fossette. Calice 

 deep, and irregularly ovate in form. 



Length 3 / 1( . inch; greatest breadth of calice about % inch. 



The specimen figured is parasitic on the ventral valve of Pro- 

 diH-tus pyxiflatus. 



Position and locality: Kinderhook group. Clarksville, Mo. 



Collector. A. H. Worthen. 



Xo. 2571 of the Illinois State Museum. 



GENUS LOPHOPHYLLUM, Ed. & Haime. 



LOPHOPHYLLUM PROFUNDUM. (sp. HOV.) 

 PL X. Figs. 1-l-Ma. 



Corallum turbinate, straight or curved, tapering regularly to 

 a pointed base: epitheca thin ; surface marked by a few distinct 

 encircling wrinkles, and numerous longitudinal striae. Calice 

 circular and deep, frequently occupying one-half the entire length 

 of the corallum: columella prominent, pointed and lanceolate: 



