Dr. H. Woodward—On the Pores in Trilobites. 537 
M‘Coy, Oldham, Salter, Barrande, and Valerian von Moller. I 
allude to certain pores more or less well-marked, and placed usually 
one on either side of the glabella in the axal furrow, and upon the 
facial suture which separates the free-cheek from the fixed one, 
forming the margin of the glabella, and just in front of the com- 
pound eyes (see Plate XIII. Fig. 5. p.). 
In working at the Silurian Trilobites Professor F. M‘Coy, in his 
“ Synopsis of the Silurian Fossils of Ireland collected by Sir Richard 
Griffith” (Dublin, 1846, 4to.), writes (p. 48), “I have observed in 
several Trilobites a peculiar pore situated in the furrow which 
separates the glabella from the cheeks near the anterior margin on 
each side, which seems to have escaped general notice, and which it 
is not impossible may be the remains of setaceous external antenne.” 
Professor M‘Ooy thinks these pores occupy just the position which 
the antennez would have occupied, and that antennz, being hollow 
organs, would leave a hole in the external integument if broken off. 
He then proceeds to observe that, “In Ampyx these punctures are 
extremely remarkable and obvious, and it is only in this group that 
they have, to my knowledge, been observed by naturalists, Captain 
Portlock! having noticed them, but without any remark, in the 
description of his A. Sarsti; they are to be seen, but not exactly in 
the right piace, in his figure of that fossil, in which they form two, 
very deep, oblong punctures, communicating with the interior; 
they are situated in the furrow before-mentioned, about their own 
length within (or posterior to) the anterior margin. I have likewise 
observed them in all the species of the genus Trinucleus. In T. 
Caractact they form two rather large circular punctures, as large as 
one of the punctures of the wings; they are in the furrows before 
mentioned, close to the anterior margin of the cheeks, communicating 
with the interior; in 1’. seticornis they form two small circular 
puncte, within the margin; they are in the same furrows, penetrate 
to the interior, and are smaller than the punctures of the wings; in 
T. radiatus they hold the same position as in T. Caractaci, that is, 
very close to the anterior margin of the cheeks. They are rather 
larger in T. elongatus, in which they occupy the same position as in 
T. Caractaci, but are smaller, and placed rather more within the 
margin. In T. fimbriatus, though small, they are very conspicuous, 
being about the size of one of the punctures of the margin of the 
shield, and their own diameter within the margin. It is very 
remarkable that those organs are most obvious in what are con- 
sidered blind Trilobites; whether it may be as a compensation for 
the want of eyes that they are furnished with better-developed 
antenns,—organs seeming so mysteriously to combine in themselves 
the exercise of all the senses, besides their own aeroscepsin, as 
Lehmann calls it,—I am unable to conjecture.” 
He adds, “ That these punctures exist, although very much reduced, 
in Trilobites with eyes, I have also ascertained, as they are found, 
although exceedingly minute, in the common Griffithides globiceps of 
1 Report on the Geology of the County of Londonderry, and of parts of Tyrone 
and Fermanagh (Dnblin, 1843), p. 261. 
