194 BULLETIN OF THE 
of secondary importance, and that, beyond a doubt, they belong to this 
group of the animal kingdom. 
2d. That they exhibit the greatest analogies with the Zsopodes, 
particularly with Cymothoa and Ligia. 
3d. That the want of feet seems to be a necessary characteristic of 
their skeleton formation, although this point still remains proble- 
matical. 
4th. That these feet, if they existed at all, were most probably 
connected with the branchial apparatus, 
These conclusions are introduced here as they evidently had much 
to do with the direction of future research, especially the 1st and 4th. 
Wahlenberg followed closely in the steps of Linneus. He believed 
that the Trilobite was most nearly allied to Limulus, and was inclined 
to transfer this similarity to the structure of the feet. The feet in the 
Trilobite, being smaller, were not observed in the fossils. He noted 
the corresponding solidity of the head-plate of the Trilobite and Limu- 
lus, and adds, that, from the various considerations given, we may 
assume that it, the Limulus, is now amongst living crustaceans the 
last remaining member of the voracious family which was formerly 
represented by the Trilobites. 
1822. “Brongniart,” Burmeister observes, “expresses the correct 
view with reference to the zodlogical relations, namely, that the Trilo- 
bites are most nearly related to the Branchiopodes among the Crus- 
tacea, and that the want of visible feet, as well as of visible antenna, 
accords very well with this.” 
1826. Dalman came to nearly the same conclusions as Wahlenberg, 
seeing a connection of affinity between the Trilobites and Limulus, 
Apus and Branchipus, and one of analogy only between them and 
Spheroma, Cymothoa, and Idotea; or, generally, of affinity between 
the Palæades (Trilobites) and Monoculi, and of analogy between the 
Palæades (Trilobites) and Onisct. 
1836. Dr. Buckland considered Serolis, Limulus, and Branchipus 
as the three living genera of crustacea to which the Trilobites were 
most nearly related. 
1843. J. E. Portlock, “Geology of Londonderry,” says: “We 
may assume a group, formed of Asaphus, Isotelus, lanus, Nileus, 
Bumastis, etc, would constitute a true connecting link in the chain 
of organization between these obscure fossil crustaceans and the recent 
genera Limulus and Apus.” 
1843. The work of Burmeister, “Organization of Trilobites,” marks 
