JULY 1899] FRESH FACTS 61 
by secreting an oily substance which keeps the water out of the respiratory 
reservoir under the elytra. The defensive apparatus of which Bordas speaks 
is the rectal pouch. 
FREEZING EGGs WITHOUT KILLING THEM. ErrenNE Rasavr. “De Vinflu- 
ence de la congélation sur le développement de loeuf de poule,” Comptes 
Rendus Ac. Sci. Paris, exxviii. 1899, pp. 1183-1185. Continuing experiments 
begun by his master, the late Camille Dareste, Mr. Rabaut finds that eggs 
exposed for half an hour in a freezing mixture at —15° C. are not killed. 
Lasting perturbations are induced, and after warming (quickly or slowly) most 
of the eggs show in three days a proliferating blastoderm spreading over the 
yolk, but without trace of embryonic differentiation. Some showed abnormal 
embryos, and a very few—proving the individuality of the egg—were normal. 
A Sexvat Pecuniariry. A. Kowatevsky. ‘“‘Quelques mots sur l Haemen- 
teria (Clepsine) costata,” Comptes Rendus Ac. Sct. Paris, cxxvii. 1899, pp. 1185- 
1188. Im this leech there is marked protandry, and exchange of spermato- 
phores occurs between the male organs at a period when the female organs are 
still rudimentary. Kowalevsky believes that the same phenomenon will be 
found to occur in other Hirudinea, such as Pisczcola, the fish-leech. 
Eee witnin Ecc. Francis H. Herrick. ‘ Ovum in Ovo,” Amer. Natural. 
xxxili. 1899, pp. 409-414, 3 figs. The occurrence of an egg within an egg is 
not a fresh fact, but it is often supposed to be. Mr. Herrick classifies the 
cases on record in two sets :—(1i) enveloping egg usually normal, but occasion- 
ally of large size; blastoderm recorded in at least one instance ; (ii) enveloping 
ege of colossal size, complete, with blastoderm probably present. One inter- 
pretation, which covers a number of cases, supposes that the small included egg 
represents a fragment of a normal ovum which has been ruptured in the upper 
part of ithe oviduct, or at least after the first layers of albumin have been 
added to the normal egg. It is possible that any substance which serves as a 
local stimulus to the upper part of the oviduct, whether coming from the ovary 
as abortive egg or egg-fragment, or from the duct as secreted product, may 
serve as a nucleus about which an egg-like body may be formed. Various 
inclusions which are not true eggs at all may be taken up by the egg and im- 
bedded in it. But in other cases, such as double or triple yolk eggs, we have 
to deal with a fusion of the albumin in two or more ova, which are treated in 
the uterus as one egg and surrounded by a single shell. This process may 
sometimes be complicated by the inclusion of a third egg of normal size and 
already covered by a hard shell. 
Excretion In Motituscs. L.Curnor. ‘“ L’excrétion chez les mollusques,” 
Arch. Biol. xvi. 1899, pp. 49-96, 2 pls. The injection method of studying the 
excretory function has led Mr. Cuénot to conclude that there are three seats of 
the process in molluscs :—(a) the nephridia, (>) closed cells isolated in the 
connective tissue or concentrated in the vicinity of the heart, and (c) in 
gasteropods, certain cells of the liver. 
CrepHALic Eyres oF Brvatves. Pav PELSENEER. “Les yeux céphaliques 
chez les Lamellibranches,” Arch. Biol. xvi. 1899, pp. 97-103, 1 pl. Pelseneer has 
now published a fuller account of the discovery, to which we previously referred 
(Wat. Sci. xiv. 1899, p. 6), and has given a plate. To what was then reported, 
we may add Pelseneer’s note that the larval eye was seen in Mytzlus and other 
forms by Loven (1848), and in Mytilus by Wilson (Lifth Annual Rep. Fishery 
Board of Scotland). Pelseneer has shown its persistence in various adults. 
As there was a misprint in one of our previous sentences, we may further note 
that the eyes do not make their appearance in J/ytz/us until after the formation 
of the first branchial filaments. 
