Discovery of Antennae of Trilob ites. — Beecher. 
305 
to the real species of the specimen figured by Linnaeus, for 
Dalman says ( loc. c it. p. 73) “ Figura haec nimis dubia a 
Wahlenberg bis citatur, scilicet ad Asaphum mucronatum, et 
deinde quoque, etsi cum dubio, ad Olenum spinulosum, quern 
me judice potius spec tare videtur.” In order to conclude this 
examination, however, it is best to accept the current identi¬ 
fication as correct, and confine our attention to the supposed 
antennae. 
Brongniart’s explanation, that the antennae in question 
were impressions of portions of the head of another individ¬ 
ual, seems unnecessary when the details of Linnaeus’ figure 
are correlated with an accurate drawing. For this purpose 
the cephalic portion of the original figure is here reproduced, 
figure 1, together with an outline of the cephalon of Parabo- 
lina spinulosa . figure 2, taken from Angelin and Brogger. 
1 2 3 
Parabolina spinulosa Wahlenberg. 
Figure 1 .— Reproduction of the cephalic portion of the specimen figured by Lin¬ 
naeus, with the supposed antennse. 
Figure 2.— Complete cephalon, after Angelin and BrOgger. 
Figure 3.—Restoration of figure 1. 
This species is a normal form, having a neck segment and 
four annulations in the glabella, figure 2.. Therefore, the pro¬ 
jecting portion of the glabella, in figure 1, is the anterior lobe 
in front of the eyes, and the margin of the head as repre¬ 
sented corresponds partly to the eye lines and to the facial 
suture. It necessarily follows that the cephalon of the speci¬ 
men figured by Linnaeus is without the free cheeks, and with 
this interpretation of the figure, the supposed antennae can only 
be homologized with the thickened border between the points 
where the facial suture cuts the anterior margin. For the sake 
of more fully showing its relations with the completed cepha¬ 
lon, figure 3 is given in which the missing parts are repre¬ 
sented by dotted lines. The comparatively small size of the 
cephalon in Linnaeus’ figure is in itself suggestive that the 
free cheeks are wanting, as is so often the case among the 
Olenidae. 
