A MONOGRAPH OF THE PHYLLOPOD CRUSTACEA OF NORTH 
AMERICA, WITH REMARKS ON THE ORDER PHYLLOCARIDA. 
By A. S. PACKARD, JR. 
PLATES I—XXXVIII. 
CONTENTS. 
I.— Classification of living species. ViI.—Relation to their environment; 
II.—Geological succession. habits. 
III.—Geographical distribution. VII.—Relations of the Phyllocarida (Ne- 
IV.—External and internal anatomy. balia) to the Phyllopoda. 
V.—Development and metamorphoses. VIII.—Bibliography. 
The Phyllopods constitute a division or suborder of the Branchiopoda, 
an order of Neocaridous Crustacea, intermediate between the Hnto- 
mostraea (represented by the Copepoda and parasitic forms or fish-lice) 
and the Malacostracous Crustacea (Tetradecapoda and Decapoda). 
They inhabit fresh water alone, in a few cases brackish water or strong 
brine, but none dwell in the sea. 
The Phyllopod Crustacea are especially characteristic of the western 
plains of our Territories, where the most striking and typical forms 
abound, one entire family (Apodide) not occurring east of the western 
edge of the Mississippi Valley, while the most bizarre member of the 
entire group, the Thamnocephalus, lives in pools on the plains of Kansas. 
These Crustacea are of singular beauty and interest in themselves. 
The outlines of the Branchipodide are interesting, and their movements 
while swimming on their backs are singularly graceful. Moreover, 
when we consider the habits of all the Phyllopods; their singular means 
of adaptation to great changes in their environment; the great vitality 
of the species; when we take into account their weak and delicate indi- 
vidual organization, and when we note their interesting metamorphoses 
and many points in their structure, we are forced to conclude that the 
Phyllopods are the most interesting of all the Crustacea. 
The materials for thismonographic account of a most interesting group 
of Crustacea have been accumulating for over ten years. 
My collection has consisted of specimens obtained by the various gov- 
ernment surveys and sent to the Smithsonian Institution, and received 
from the late Dr. Stimpson, secretary of the Chicago Academy of Sci- 
ence, shortly before the fire which destroyed the museum of the acad- 
emy. A large and very valuable collection was made for me by Dr. L. 
Watson, of EHllis, Kans., while a very valuable collection from Fort 
Wallace, Kansas, has been kindly loaned me by Prof. Joshua Lindahl, 
of Augustana College, Rock Island, Ill. Iam also indebted to the Pea- 
body Academy of Science, Salem; the Museum of Comparative Zoology 
at, Cambridge, for the loan of specimens, as well as to the Museum of 
Yale College; and to Dr. C. F. Gissler, Mr. W. P. Seal, Mr. 8. A. Forbes, 
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