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sects, and in its double outlet to the Crustacea and Araclmida. He 
also institutes a comparison between the structure of the male and 
female organs in this Myriapod, which, from their simplicity, admir- 
ably illustrate the uniformity of origin of these structures ; more espe- 
cially the analogy between the ovisacs in the female and the caeca in 
the male, and also their conformity in the absence, in the latter, of se- 
parate vesiculae seminales, and, in the former, of spermatheca. 
The second section is occupied by a short account of the structure 
of the ovum, in which the author observes the germinal vesicle and 
macula. He notices especially the presence of the yelk in the ear- 
liest stages of developement, together with the vesicle and the mem- 
branes of the ovum at a later period, as showing in this low form of 
animal the conformity of structure and laws with those which pre- 
vail in the higher forms. 
In the third section, the author speaks of the deposition of the 
ova, and of the habits of the species, as observed in specimens col- 
lected and preserved by him for that purpose. These habits he re- 
gards as particularly curious. The female excavates for herself a 
burrow, by digging with her mandibles in the soil, which she has 
previously moistened with a fluid, supplied, as the author believes, by 
her immense salivary glands. With this she forms a soft pellet, which 
she removes from the burrow with her mandibles and anterior legs ; 
and thence, after being brought to the top of the hole, it is passed 
on to the next pair, and by these on to the next in succession, until 
it is entirely removed out of the way ; after which, she deposits her 
eggs and closes the burrow with moistened clay. Great difficulty was 
experienced in preserving the eggs during the observations, from 
the circumstance that their shell is soft, and dries quickly when ex- 
posed to the air. To avoid this, the author had recourse to the plan 
of inclosing the eggs in a glass tube, filled with clay, and closed 
with a cork ; the eggs being placed in a cell next to the glass. 
The fourth section, which constitutes the most important part of 
the paper, gives the history of the evolution of the embryo. The 
process is divided by the author into different periods. After a few 
observations on the earlier changes of the egg, and the proof that they 
consist in an alteration in the size and appearance of the cells out of 
which the embryo is formed, he states his having observed that the 
egg bursts at the end of twenty-five days, by means of a fissure along 
the dorsal surface, as described by Savi and Waga ; and that, in oppo- 
sition to the remarks of Degeer, the young Julus, as first stated by 
Savi, is perfectly apodal. The author has also discovered a singular 
fact, entirely overlooked by all who have attended to the developement 
of these animals, namely, that the young Julus at this time is still an 
embryo, and is completely inclosed in a shut sac, which terminates 
in a distinct funis at the extremity of the body, and in the proper 
amnion, or foetal envelope of the animal. He finds, also, that the funis 
enters at the posterior penultimate segment of the dorsal surface of 
the body, and not at the dorsal surface of the thoracic region, as 
seen by Ilathke in the Crustacea. The embryo, he says, is retained 
in connexion with the shell, between the two halves of it, for seven- 
