Dr. H. Woodward—On the Pores in Trilobites. 5389 
partially cleft borders,—may be exhibited together, in order to 
demonstrate the supposed origin of the structure” (p. 253). 
In another paragraph in the same paper, Salter refers to the dis- 
covery by himself and Emmrich of the facial suture in Trinucleus 
ornatus, ‘its course (he states) is obliquely upwards from the eye 
tubercle to the upper end of the glabella, where it appears to termi- 
nate in a solitary deep perforation, similar to those which surround 
the head” (op. cié. p. 251). It is to these pair of deep puncta, one 
on either side of the head, that we would specially draw attention. 
Later on (in 1852), Mr. Barrande, in his “Systéme Silurien de la 
Bohéme” (vol. i. Trilebites, p. 230) thus wrote, “On the antenne of 
Trilobites—Piof. M‘Coy in his work already cited (p. 45) announces 
what he deems to be the discovery of the remains of antennze in the 
form of a deep pore on either side of the frontal lobe in the groove 
which surrounds the glabella. He enumerates the genera Trinu- 
cleus, Acidaspis, Calymene, Ampyx, Griffithides, etc., in all of which 
this observer states he has succeeded in tracing these organs. We 
have also remarked these puncta long since in a variety of Trilobites 
from Bohemia, notably in Calymene, Trinucleus, Cheirurus, but we 
have been led to offer a different interpretation to that indicated 
above. 
“First we have to observe that if this cavity does not appear to 
be anything else but a pore in those species with a border, as Trinu- 
cleus, it assumes larger and larger dimensions as it approaches the 
edge of these Trilobites, and forms a funnel-shaped opening nearly 
2mm. in diameter in the head of Cheirurus claviger.” } 
““When the shell exists, as we have seen it in specimens of 
Calymene Baylei, Cheirurus gibbus, ete., it is bent inwards, as a 
funnel-shaped depression. We have thought that this bending in- 
wards of the shell was simply designed to afford points of attach- 
ment for the muscles of the jaws and that they had the same origin 
as the similar indentations which we have indicated in the pleure 
of various species of Trilobites. We have observed the conformity 
of the position of these pits in the depression of the axial furrows of 
the thorax as in the head. We recall again the indentations of the 
shell on the glabellal furrows and on those of the axis of the pygidium 
in Dalmannia. 
‘We were satisfied with these analogies and we sought no other 
explanation for these little indentations. But after having read the 
opinion of Prof. M‘Coy we have studied all the specimens afresh 
which might serve to elucidate this question, and we have found 
a portion of a Cheirurus gibbus which seems to explain the matter 
satisfactorily to our views. This fragment is broken along the line 
of the dorsal groove and the length of the glabella exposing to view 
one of the ale of the hypostome in siti. This wing of the hypo- 
' This is not shown in Barrande’s figures of Cheirurus claviger, pl. 40, figs. 1—12, 
nor in Ch. gibbus, figs. 35—39, but is seen in pl 41, fig. 17; it is also well shown 
in Trinucleus ae pl. 29, figs. 1—8, and in Placoparia Zinpei, pl. 29, figs. 30— 
34; and in Calymene Bag ylei, pl. °43, fic. 49, and in many others, not referred to 
by Barrande. 
