376 PALEOZOIC PALEONTOLOGY. 
convex and have less angular plications than that species, and they 
seem to agree essentially with the larger specimens, which exhibit more 
typically the characters of S. macrothyris. 
SPIRIFER sp. undt. 
Plate LII., Fig. 4. 
Description——A single, fairly well-preserved specimen of the 
brachial valve of a Spirifer has been observed from the Newfound- 
land locality which cannot be definitely identified with any of the 
described species. It is nearly semi-circular in outline, with the 
hinge-line equaling the greatest width and with angular cardinal 
extremities. The mesial fold is not greatly elevated above the 
general surface, and is marked along its median line by an angular 
furrow much deeper and wider than the furrows which separate the 
plications upon the lateral slopes of the valve. Each lateral slope is 
marked by eleven or twelve angular plications which become smaller 
and smaller toward the cardinal extremities. 
The dimensions of the only specimen observed are: length, 16 mm. ; 
width, 30 mm. j 
Remarks.—The peculiar feature of this species is the deep furrow 
along the mesial line of the fold. Spirifer pennatus Atw. frequently 
has a similar mesial furrow, but it is never so conspicuous as the 
furrows on the lateral slopes of the shell, and, moreover, the New 
Jersey specimen does not possess the extended hinge-line of that 
species. Spirifer consobrinus D’Orb. is another species which fre- 
quently has a furrow upon the mesial fold of the brachial valve, but 
the furrow is never so prominent as in the New Jersey specimen, 
and the fold itself is much more elevated in front. The finer surface 
markings are not preserved on the New Jersey specimen, so it cannot 
be determined whether or not it resembles S. consobrinus in this 
character. 
