SOME NEW DEVON IC EOSSILS 



259 



side and each of the large ones bears a slight furrow along its 

 flat top. The median fold is relatively narrow and not highly ele- 

 vated. The shell is short-hinged and rotund in form. The sur- 

 face is covered with close concentric fimbriate lines which bend 

 backward at the middle of each sulcated rib. I have seen but a 

 single dorsal valve of this interesting species but its differential 

 characters are very distinct. 



Lower Devonic. Edmunds Hill, Chapman Plantation, Me. 



Spirifer macropleuroides nov. 



The Chapman Plantation fauna carries a representative of the 

 Radiati or group of Spirifer plicatellusina species which 

 has the aspect of a small Sp. macropleura Conrad, 1 an ex- 

 treme expression of the form presented by S. togatus Barrande 

 and variety subsinuata A. Roemer 2 ; the first from the New 

 Scotland Helderbergian of New York and the others from the low- 

 est Devonic of the Hartz and Bohemia. 



In S. macropleuroides the shell is more sharply plicate 

 than in the others, the plications being two or three in number 



Spirifer macropleuroides 



on each side of the median fold or sinus. Neither of the latter is 

 extremely developed, being broad and regularly rounded ; the lat- 

 eral plications are strong and broad, evenly rounded and with 

 narrow grooves. The surface is covered with very fine longitudi- 

 nal striae. The shell is distinct from S. macropleura in its 

 smaller size and stronger plications, in which respect it is the most 

 progressed of all the three forms above mentioned. 



Lower Devonic. Edmunds Hill, Chapman Plantation, Me. 



iHall. Pal. N. Y. 3:302, pi. 27. fig. ia-p; pi. 28, fig. 8a-d. Hall & Clarke, ibid. 



pi. 21, fig. 22-24, 27. 



2 Kayser. Aelt. Devon-Ablag. d. Harzes. pi. 21, fig. 3 and fig. 1, 2, 7. 



8, pt 



