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MORPHOLOGY AND FAUNAS. 191
phosis of the natatorial feet to the mandibles and maxilla?, and
the formation of a dorsal shield, both lying between the stages
of Nauplius and Zoea, are fully discussed. Then the author'
proceeds by acknowledging the existence of a gap between Zoea
and the Phyllopods; but nevertheless he thinks probable that
all the present orders of the Crustacea did originate from Phyllopoda.
These separated themselves into two branches : some,
remaining natatorial, and transferring the respiratory function
from the dorsal shield to the natatorial feet, gave origin to all
Podophthalma and Edriophthalma (the recent genus Nebalia is
regarded as representing a link in the chain of this transformation)
; others, losing more or less their natatory propensities,
and developing the dorsal shield into a strong mostly bivalve
shield sufficient for protecting the whole body, which becomes
shortened for this purpose, gave origin to the Ostracods, Cirripeds,
and even to the Copepoda. The Trilobites belong also to.
this stage of historical development. The question whether the
Ostracoda can be reduced to transformed Phyllopoda, which
Prof. Claus is inclined to maintain and F. Mfiller to deny, is
fully discussed, chiefly with regard to the organization of the
genus Cypridina, and fully upheld. Jen. Z. Nat. vi. pp. 96—
156.
In some specimens of Astacus (Cheraps) preissii (Erichs.), which have the
internal and external male organs well developed, an analogue of the orifice
of the female organs has also been observed in the chitinous tegument by
the Recorder. SB. nat. Fr. 1870, p. 1.
CONTRIBUTIONS TO FAUNAS.
A. METZGER gives a list of Crustacea observed hitherto on the coast of
East Friesland (between the mouths of the rivers Ems and Jahde), containing
24 species of Decapoda, 19 Amphipoda, including 2 Lasinodipoda, 7 Isopoda,
5 free Copepoda, 10 parasitical Caligidas and Lernasidee, 8 Cirripeda (and
3 Pycnogonida). Their modes of occurrence are accurately stated. JB. Ges.
Hannov. pp. 31-33.
The Gammaridse (3 species), Lynceidse (6), and Cyprida (23) of the fresh
waters of Belgium are given by F. Plateau, Mem. cour. Ac. Belg. xxxiv.
1869-70; the Daphniidas and Cyclopidse in the following volume (xxxv.),
1870.
The Ostracoda of the tidal rivers of the eastern parts of England,
especially the tidal lakes or " broads" of East Norfolk,
have been examined by H. G. BRADY. Although the water of
most of them is perfectly fresh, there have been found many
new and highly interesting species and even genera, the most
characteristic of which are Goniocypris mitra, Metacypris cordata,
Polycheles stevensoni, and Cythere fuscata. Some of them
have been found also in the Dutch rivers Meuse and Scheldt.
The author is not inclined to ascribe the presence of these and