370 GEOLOGICAL SURVEY OF THE TERRITORIES. 
SPECIES INHABITING THE INDO-AFRICAN REALM. 
a. African Region. (Central Africa, White Nile; South Africa, Cape 
ot Good Hope.) 
Limnetis wahlbergi. Port Natal. 
Limnadia africana Brauer. White Nile. 
Estheria rubidgei. Cape of Good Hope. 
macgilivrayi. Cape of Good Hope. 
australis. Caffer-land. 
Apus dispar Brauer. White Nile. 
sudanicus Brauer. Chartum. 
Branchipus abiadi Brauer. White Nile. 
Streptocephalus cafer. Port Natal. 
vitreus Brauer. White Nile. 
proboscidens Frauenfeld. Chartum. 
b. Indian Region. 
Estheria compressa. India. 
hislopi. India. 
polita. India. 
boysti. India. 
similis. India. 
Branchipus dichotomus. India. 
Apus granarius. Peking. 
SPECIES INHABITING THE AUSTRALIAN REALM. 
Limnetis maclayana. Australia. 
Limnadia stanleyana. Australia. 
Apus viridis. Tasmania. 
angasit. Australia. 
Apus sp. New Zealand. 
Lepidurus kirki Thompson. New Zealand. 
compressus Thompson. New Zealand. 
From these data it appears that but a single genus is peculiar to 
North America, 7. e., Thamnocephalus; while Polyartemia is peculiar to 
the Europxo-Asiatic Region; all the other genera occur in nearly all 
of the continental masses of the globe, though no Branchipodide occur 
in Australia, and no Limnadia has yet been found in Asia. This cos- 
mopolitan distribution of the Phyllopoda (the Branchipodide, the high- 
est family, being excépted) poimts towards the high antiquity of this 
group of fresh-water crustacea. The distribution through ZONES across 
continents, noticed by Gerstaecker, appears not to be exceptional to 
that of other classes. We have noticed it in Geometrid moths, and 
also in mammals, the central portion of Asia repeating the characteris- 
tics of Central North America. 
IV.—_MORPHOLOGY AND ANATOMY. 
A transverse section of the anterior part of the body of any genus of 
Phyllopods will convey an excellent idea of the leading features in their 
organization, especially those by which they differ from the members of 
other Crustacean orders. The leading topographical features in the 
body, particularly of Arthropods, are the form of the elemental seg- 
ments with their appendages, and the relations of the principal anat- 
omical systems to the body walls. 
General relations of the systems of organs to the body-walls.—We will first 
- look at sections of representatives of the three families of Phyllopods ; 
4.e., an Hstheria (Plate XXIV, figs. 9,10), Apus, Plate XX XII, fig. 2 (see 
also fig. 25 in text), and a Branchiopod, such as Thamnocephalus (Plate 
