28 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
The Calymene abundant at Waldron, Indiana, has always been 
identified with C. niagarensis, but differs from that species in at least 
two marked details. The first and most obvious characteristic is that 
there is no lip, nor any furrow between the glabella and the rim, so 
that the glabella reaches upon, and in some cases, overhangs the rim, 
a feature usual in the Cheiruridae but extremely uncommon among 
the Calymenidae. This gives the cephalon the high, short appearance 
which suggested the name breviceps. On the pygidium the ribs reach 
nearly to the margin but become faint on approaching it. Ordinarily 
the ribs do not bear any median impressed line though traces of one 
may be seen on some specimens. 
This species is in many ways much like C. celebra, the next species 
described. 
Formation and locality: — This species is so far known only from the 
(Silurian) Waldron shale at Waldron, Indiana, where it is very com- 
mon. 
CALYMENE CELEBRA, Sp. Nov. 
Plate 3, fig. 9, 10. 
Calymene blumenbachii var. niagarensis Hall, Geol. surv. Wisc., 1862, 1, p. 432. 
Calymene niagarensis Hall, 18th Rept. N. Y. state cab. nat. hist., 1865, p. 30, 
adv. sheets; 20th Rept. N. Y. state cab. nat. hist., 1868, p. 334; 1870, 
rey. ed., p. 425. Weller, Bull. Chicago acad. sci., no. 4, pt. 2, p. 261, pl. 
93 1£..9°10: 
One of the most abundant of the trilobites of the Chicago area and 
of southeastern Wisconsin is a Calymene which is constantly identified 
as C. niagarensis. It is quite commonly found entire, but always so 
far as I have seen in the condition of a cast of the interior. Moulds 
of the exterior are common, but seldom complete. 
The cephalon is like that of C. niagarensis, with a short lp and 
narrow furrow in front of the glabella. The dorsal furrows are always 
very deep and sharp, but this is due to the state of preservation. The 
glabella tapers rather abruptly toward the front. The basal lobes are 
large, rounded, almost isolated; the second lobes small and rounded, 
the intermediate “extra lobes”? not very prominent. The third lobes 
are very small and the fourth ones just barely indicated. The frontal 
lobe is short and rather square at the front. The eyes are close to the 
glabella and opposite the furrows between the second and third pairs 
of lobes. 
