526 THE AMERICAN NATURALIST. (Vot. XXXII. 
Embryonic Budding in Hymenoptera. — Mr. Paul Marchal has 
recently published in the Comptes Rendus of the French Academy a 
. preliminary account of a peculiar method of a sexual reproduction. 
The chalcid parasite Encyrtus lays a single egg in each egg of the 
moth Hyponomeuta. Like other chalcid eggs, this is at first sur- 
rounded by a cellular envelope ; the cells of this multiply rapidly and 
develop into a long epithelial tube within the parasitized egg. The 
egg proper divides, and the divided portions separate, each one giving 
rise to an embryo, so that from one egg from fifty to one hundred 
embryos arise, lying like a chain in the epithelial tube, each of which 
gives rise to an Encyrtus like the parent. The author is at a loss to 
suggest a parallel to this method of reproduction among the Metazoa. 
The case of Lumbricus, as first described by Kleinenberg, at once 
suggests itself; and then there is that interesting case described by 
Agassiz in his “ Methods of Study in Natural History,” according to 
which the egg of our common sea snail Natica undergoes its third 
segmentation, and then from each of the resulting eight cells an 
embryo develops. Has any one yet confirmed this observation, or, 
if it be erroneous, has any one explained how the mistake arose ? 
The Cyclostome Pronephros. — In spite of the enormous literature 
on the pronephros, there are yet many points of fundamental impor- 
tance unsettled. The recent papers of Rabl, van Wijhe, Felix, Field, 
Semon, and Price show many points of difference and few of agree- 
ment. The latest paper to come to our notice is that by S. Hatta 
(Annotationes Japonica, vol. i, 1897), upon the pronephros of the 
lamprey. Hatta claims that both the pronephric tubules and the 
pronephric duct arise from the region of the unsegmented mesoderm, 
but that the tubules at first correspond to the more dorsal segments. 
At most but six pairs of pronephric tubules are formed, the first and 
second of these in the segments where the posterior gill-slits later 
appear. These tubules, together with the sixth, disappear. Hatta 
regards these tubules as homologous with the Nierencanalchen of 
Amphioxus. 
Marine Character of African Lake Fauna. — Mr. J. E. S. Moore 
recently read a paper before the Royal Society upon the results of 
his studies of the invertebrates of Lake Tanganyika, Africa. He 
points out that the fauna of this lake is strikingly unlike that of the 
other African lakes, Nyanza, Shirwa, and Kela, and that it has a 
facies peculiarly marine and of deep-sea forms at that. His conclu- 
