Hitchcock.] 
120 
[Dec. 19, 
Of lower arthropods and worms there may be half a dozen new 
species and two new genera. 
Summary. 
Marsupial, 
1 
Hexapod arthropods, 
24 
Pachydactylous birds, 
17 
Lower arthropods and worms, 
16 
Leptodactylous birds, 
18 
Mollusca, 
6 
Dinosaurs, 
28 
Incertae sedis, 
6 
Reptiles and amphibia, 
27 

Batrachians, 
16 
165 
Chelonians, 
6 
The class of Birds is still retained for convenience, although 
the bones found in the west seem to point to reptiles as most prob- 
ably the animals thus designated. It is still a fact that such 
special reptilian characteristics as would be exhibited in walking 
are absent in the genera Brontozoum and Grallator, while those 
creatures called Dinosaurs are thus referred, either because of the 
marks of front feet, heels to the hind feet or of tails. The bird 
group is also characterized by long legs, while most of the Dino- 
saurs had short legs, as indicated by their numerous steps. I do 
not change the reference of a group to Chelonians, though it is 
not satisfactory. 
The Arthropoda are most likely to be referred to the lower 
classes ; yet the presence of only six feet in the impressions leads 
us to speak of them as Hexapods. They may not be true insects, 
but larval forms requiring further investigation before satisfactory 
references can be made out. Further statement of the reasons for 
referring various imprints to their lowly owners would involve a 
discussion of the third part of the subject which cannot be under- 
taken now. 1 
It will be proper to state a few facts about museums and locali- 
ties before describing the new species. 
THE AMHERST MUSEUM. 
A few slabs have been added since 1865, and the arrangement 
of the rooms has not been changed since the printing of the cata- 
logue. One slab shows a Brontozoum with two toes on one foot and 
three upon the other, as if the owner had lost a toe by fighting or 
1 Of modern authors, A. G. Nathorst has treated of the invertebrate tracks most fully 
in his Memoir sur quelques traces cPanimaux sans vertebrae , etc., et de leur portee pa- 
leontologique, 1880. His bibliography notices several American authors, but he has evi- 
dently not seen the Ichnology of Massachusetts. 
