274 W. H. SHERZER — THE GENUS CHONOPHYLLVM. 



" ( 'o rail mil simple, broadly turbinate, regularly expanding; exterior with numer- 

 ous concentric wrinkles and striatums. Externally there are numerous slender 

 processes, quite evenly distributed, which served for attachment and support ; 

 when exfoliated the exterior has a somewhat compressed vesiculose appearance; 

 corallum consisting of thin, superimposed laminae; height 35 mm; diameter of 

 calix 60 mm; depth 12 mm; for a distance of 20 mm from the margin it is 

 gently sloping, then nearly vertical ; a convex space at the bottom 15 mm in diam- 

 eter; tabulse thin; fossette small, deep, not extending on the side of the calix- 

 number of lamellae 160, alternating in size, the smaller ones rudimentary, not more 

 than one-sixth the thickness of the others; near the margin the larger ones are 

 broad, angular, having a width of about 1.50 mm becoming thinner as they ap- 

 proach the center where they are twisted and elevated, forming a false columella. 



" This species has nearly the same form as P. [Ptychophyllum"] fulcratum ; it has also 

 similar processes for attachment, and might, on a cursory examination, be mistaken 

 for that species, but it is much more distinctly composed of thin, invaginated 

 lamina'; the lamellae are decidedly alternating in size and there are well devel- 

 oped tabulae. 



"Formation and locality. Niagara limestone, Louisville, Kentucky." 



The deep fovea, angular septa, well developed tabulae, invaginated 

 laminae, false columella, and radiciform processes leave no doubt but 

 that we have here a genuine Ptychophyllum. 



In the plates of Kentucky corals * for which no text has yet been 

 issued, Mr. Davis figures two supposedly new species of Chonophyllum 

 from the Devonian and assigns the specific names, nanum and multipli- 

 cation. The photographs reveal no structure in either which can bring 

 them into this genus. 



From this list of species we have found C. perfoliatum, C. magnificum, 

 C. ponderosum and possibly C. belli, which possess structures sufficiently 

 closely related to permit of their being grouped under one genus. 



Description of New Species. 



(Plate 8, figure 6.) 



We have made a study of two forms, not previously described, which 

 are most properly referred to this group, and we append descriptions. 

 The first is of a specimen collected from the Upper Silurian of Conje- 

 pruss, Bohemia, by Dr. Rominger, and described here with his permis- 

 sion. The name pseudohelianthoides is of his suggestion. The second 

 species is founded upon a specimen from Louisville, Kentucky, collected 

 by Mr. G. K. Greene, in whose honor it is named. 



*A Monograph of the Fossil Corals of the Silurian and Devonian Rocks of Kentucky, pt. ii, 1885, 

 pi 78, fig. 6, and pi. 80, figs. 11, 12 and 13. 



