1883. | Physiology. 337 
projector of the series, Mr. Agassiz, the curator of the museum, 
these selections “will give to the student, in an easily accessible 
form, a more or less complete iconography of the embryology of 
each important group of the animal kingdom. This selection is 
not intended to be a hand-book, but rather an atlas to accompany 
any general work on the subject.” 
The Crustacea appeared last year, the bibliography having been 
prepared, and the plates selected by Professor W. Faxon. The 
lithographic work is well done, and considerable new matter by 
oth Mr. Agassiz and Professor Faxon has been added in the 
plates; the most noteworthy being the early stages of the hermit 
crabs, and the barnacles. The phenomena connected with the 
fecundation and maturation of the egg, and the history of the for- 
mation of the embryonic layers, will be treated of in a separate 
part. The parts devoted to Echinoderms, Acalephs, and Polyps 
are in an advanced stage of preparation. We have detected no 
omissions of importance in the part already issued. 
A Myriopop wuicu Prouces Prussic Acip.—In several of the 
hothouses in Holland, a Myriopod is frequently met with which 
(according to Herr Weber, of Utrecht), is a foreign species of the 
genus Fontaria, and has the remarkable property of producing 
prussic acid (HCy). Attention was called to this on finding that 
the animal, when excited, gave out a strong smell of oil of bitter 
almonds. The phenomenon is still more pronounced on bruising. 
me specimens having been distilled with water, prussic acid was 
found in the distillate. Herr Egeling has lately made a series of 
experiments to test the view that this Myriopod prepares a sub- 
stance which, under certain conditions, is decomposed, giving 
Prussic acid as one of the products of decomposition. This was 
fully confirmed. By action of various reagents, a substance was 
detected, which is split up by water, yielding HCy. It further 
seemed probable that, besides this substance, the animals possess 
one which acts as a ferment, and which the author hopes to be 
le to separate.— English Mechanic—[Note. The Fontaria vir- 
gmica, a common Myriopod in Pennsylvania, has long been 
known to emit a powerful smell of Prussic acid.—E. D. Cope.] 
THE Trachea AND THE Source OF LIGHT IN FirEe-FLIES.— 
Nature gives an abstract of Wielowiejski’s account in the %ert- 
schrift für Viissenschaftliche Zoölogie, of the light-producing or- 
_ in Lampyris Splendidula and noctiluca. He sums up the 
ost ‘important results as follows: .1. The “ tracheal terminal 
respiratory tubes ; for these branch out further on into brush-like 
Masses of much: finer capillaries, which are without the chitinous 
Spiral ; they are very attenuated, and making their way in to the 
Peritoneal layer, are numerously distributed to phosphorescent 
