202 | Cincinnati Society of Natural History. 
These numerous references and quotations are given to show the 
distrust and uncertainty in the minds of prominent naturalists as to 
the limbs of the Trilobites, 
In the autumn of 1882 the Trilobite, Asaphus megistos (Fig. 1), 
was sent me for examination. In the delay of correspondence with 
paleontologists, fortunately, no report was made, for in the spring of 
1883, twelve months after finding the first specimen, the same party 
found the second, which proved to be the matrix of the ventral sur- 
face of the first specimen. It was found about one hae meters 
from the point where the first was obtained. 
About two thirds of the cephalic shield is broken off. That part of 
the head anterior to a line drawn obliquely through the left eye to the 
middle of the pleura of the second thoracic somite on the right is en- 
tirely wanting. With the head restored, the specimen would be about 
18.5 centimeters (72 inches) long; in width, 11.5 centimeters (about 
4} inches), On the ventral surface (Fig. 1) a broad median groove 
extends along the concavity of the thorax and abdomen. It begins 
at a point beneath the articulation of the head with the thorax, or in 
the posterior part of the area between the lobes of the hypostoma. 
Its length is 10.5 centimeters (44 inches )—6.5 centimeters being the 
length of the thoracic, and four centimeters that of the abdominal 
portion of the groove. This specimen clearly demonstrates the con- 
cavity of the three principal divisions of Asaphus, a fact which Mr. 
Billings pointed out in 1864. The vertical distance from the dorsal 
surface of the head to a line in the plane of the external margins of 
the pleure is 2.5 centimeters (about one inch). 
Directly beneath the eight somites of the thorax, ten pairs of jointed 
limbs are distinctly seen; the two anterior pairs of appendages are 
situated directly under the first two thoracic segments; but from the 
character of these appendages, as well as the relation of parts, these, 
while having the general appearance of organs of locomotion, yet 
were, no doubt, maxillipedes with the basal joints articulated to the 
body of the animal, near the point where the oral aperture certainly 
existed, and presumably they were differentiated to perform the func- 
tion of mouth organs, and consequently should be considered as: 
belonging to the cephalic division. The remaining eight pairs of legs 
are then directly referable to the eight thoracic somites. The number 
of joints in a limb can not be definitely given from a study of these 
specimens; the basal joints are not preserved at the median groove. 
Following the terminology of Milne-Edwards for the several parts 
of the limb of a crustacean, the prominently-marked portion of these 
ambulatory limbs is undoubtedly the meropodite, which was in some 
