35. CONTRIBUTION TO 



the bottom of the ealix, where the short ones gradually disappear; the longer 

 ones continue, coalescing with the tabulae, to within two or three millimeters of 

 the center of the calix, and abruptly terminate, leaving a smooth, depressed 

 space in the bottom of the ealix, from four to six millimeters in diameter. Ex- 

 terior with rough distant annulations, sharp, and deep constrictions, caused by 

 periodical growth. Fossette consists of a deep depression at the margin of the 

 smooth depressed space in the bottom of the calix, and extends to the anterior 

 margin. Denticulations fine, but not closely arranged. 



The specific name is in honor of Prof. Will H. Sherzer, Professor of Natu- 

 ral Science in the State Normal School, Ypsilanti, Michigan. 



Found in the middle Devonian (upper Helderberg group), at the Falls of 

 the Ohio. Now in the collection of the author. 



HELIOPHYLLUM MINUSCULUM, N. Sp. 



Pate 18. Figs. 7-8. 



Corallum simple, turbinate, straight or regularly curved, with a broad scar 

 at the point of attachment. Gradually, or in some examples, more rapidly ex- 

 panding in diameter to the calix. Height twenty-five millimeters. Diameter 

 of calix twenty millimeters. Depth fifteen millimeters. With an oblique con- 

 vex space in the bottom of the calix, occupied by the tabulae, eight millimeters 

 in diameter. Number of lamellae ninety-four, in the circumference of a calix 

 twenty millimeters in diameter; unequal in size, and sharp at the margin, alter- 

 nating below, gradually sloping to the bottom of the calix, where the short ones 

 terminate ; the longer ones continue coalescing with the tabulae ; a few extend 

 to the center of the cup, and abruptly end. There are two fossettes, situated 

 on the posterior, and anterior sides, the principal one is situated on the anterior 

 side ; both of them commence at the margin of the concave space, and extend to 

 the margin of the calix. Denticulations rather coarse, one millimeter apart. 

 Exterior with irregular annulations, and shallow constrictions, caused by periodi- 

 cal growth. 



Found in the middle Devonian (upper Helderberg group), at the Falls of 

 the Ohio. Now in the collection of the author. 



HELIOPHYLLUM LEMONI, N. Sp. 



Plate 14. Fig. 17. 



Corallum simple, or composite, increasing by calicular gemmation. Acute 

 at the base of attachment. Rapidly increasing in diameter to the calix. 



