ANATOMY AND EMBRYOLOGY. 
Grust. 3 
may be those which most resemble the primordial ancestors of all 
Crustacea ; the Limulidce, Trilohitidce, and EarypteridcB may be some of 
the earliest offshoots of that stem ; he comprises these 3 families under 
the name Crustacea polygnatha, because in them several pairs of 
extremities unite in themselves the manducatory and walking functions. 
The Osiracoda may be derived from the Phyllopoda by a closer adapta- 
tion of the body to the surrounding shield, and the Cladocera are linked 
with them by Estheria. The Copepoda form another distinct branch, 
and from them the Cirripedia are to be derived ; the hermaphroditism 
of the latter may be secondary, caused by the fixed life. On the same 
line with the Phyllopods, the author ranges the presumed primordial 
Malacostraca, to which he ascribes a lengthened chambered heart, a 
second pair of antennae, the nerves of which were furnished by the infra- 
pharyngeal ganglion, a dorsal shield starting from the maxillary region, 
eight thoracic segments with eight pairs of feet, and, clearly distinct from 
them, seven abdominal segments with natatory feet and tail fin ; seven 
pairs of feet (including gnathopods, &c.) in them are morphologically 
identical with those of the Entomostraca or the above-mentioned orders 
of Crustacea, the others are new ; Nehalia and Branchipus among the 
living forms may give an approximate idea of those primordial forms, 
from which the Decapods, Stomapods, Amphipods, and Isopods are to 
be derived. The metamorphosis of Eupliausia, and in some degree also 
that of Peneus, illustrates the gradual progress from the primordial 
forms to the Decapoda Macrura. The Isopods deviate more than any 
other order from the common type of the Crustacea, and their develop- 
ment is the most shortened, the intermediate transitory stages being 
suppressed. 
In the Schuopoda and Pcneidcv, the larva is hatched as a Nauplius, 
and undergoes its further development in free life ; the rest of the Carides 
go through the stage of Nauplius and Protozoea within the egg, and the 
first stage of free life is that of Zoea mingled with features of the 
Mysis-Vi^Q stage. The Thalassinidce and Paguridce are hatched in the 
.Zoea-stage. The cephalothorax of the Decapoda appears to take its 
origin from the shield of the Nauplius (p. 53). 
[The Recorder has entered, contrary to his system, into such theo- 
retical and 'hypothetical views, as they are brought forward by an acute 
and exact observer who has a thorough knowledge of the subject, and 
opposes himself to the wild speculations of some proclaimers of the 
transmutation theory.] 
C. Spence Bate has observed the larva of the following genera of 
stalk-eyed Crustacea : Stenorrhynchus, Lihinia, Mencetius, Mitlirax ; Car- 
pilodes, Liomera, Actma, Xantlio, Pilumnus, Eriphia, Melia, Trapezia, 
Pirimela, Thalamita, Achelous ; Gelasimus, Cyclograpsus ; Thia, 
Trichia ; Pagurus, Clihanarius ; Porcellana, Galatea ; Palinurus, 
Tlomarus, Astacus, Thalassina ', Crangon, Alpheus, Hymenocera, Paloe- 
mon ', Squilla. Some of the species are British, the majority foreign ; 
the latter have been hatched from the eggs by W. H. Power, and the 
parents of all have been identified. He adds interesting observations on 
the change in form of the embryo within the egg, homologous with the 
