156 NATURAL HISTORY MISCELLANY. 
suggested that the modern Phyllopods, such as Apus and E 
cent 
certain Silurian Copepoda and Os da e accounted ori 
of these forms rather by a process of acceleration and retardation 
of development as suggested by Messr Cope* an att,ł involv- 
intermediate generic forms as we do not find i or fossil. He also 
thought that the study of the facts of Dimor phism and Parthenogenesis, 
and the mode of production of the more remarkable sexual differences 
among animals, would throw light on a comprehensive theory of evo- 
lution. 
NCESTRY OF INSECTS. — Referring to his discovery of Pauropus 
in this country, and mentioning the six-legged form of the young, and its 
resemblance to Podura, and comparing it with the Hexapodous young 
of Julus and the young of certain mites, Dr. Packard, at the same meet- 
ing, referred the ancestry of the Myriapods, Arachnids, and Hexapodous 
Nauplius fo ong Crustacea, inasmuch as the body is not 
differentiated into a head, thorax or abdomen, and there are three pairs 
of temporary appen e Nauplius, which was first supposed 
dage Lik 
to be an adult Etioniltricsii: the larval form of Trombidium, had been 
described as a genus of mites under the name of Leptus (also Ocypete 
and Astoma) and was supposed to be adult. 
For this primitive, ancestral form he proposed the term Leptus. He 
suggested that the ancient Leptus may have descended through Demodex 
from some Tardigrades, and that this latter group had perhaps descended 
y 
parallel line of descent through some Leptiform Silurian insect resem- 
bling the young of Stylops, Meloe, and low neuropterous or orthopterous 
larve, and the Thysanura, such as Podura and Lipura. He did not regard 
the insects as having been evolved either from a zoéa o r Nauplius form, 
but would refer the ancestry of both classes e Insects and Crustacea), 
testem of each other, to the worms (Annulata 
MONTEREY IN THE DRY SEASON. — On ders to the coast from the 
Colorado AES in May, 1861, my health impaired by the tropical heat of 
he last two months at Fort Mojave, and by the too sudden change to the 
emi climate of the coast, I was glad of the opportunity of recruiting it 
by some weeks devoted to collecting marine animals, etc., at Monterey. 
* Origin of Genera. ee 1868, 
` f Parallelism betw e order and individual ie the i Fotarto Cephalopods. Me- 
of the Boston Fel of Natural History. and AMERICAN NATURALIST, Vol. 4, 
