In the presence of a section of the body cavity in the head the embryo of Sagitta resembles Lumbricus, Spiders, etc.
Sagitta: arrow-like spots on the wings of Lepidoptera and other insects.
In Sagitta the formation of the mesoblast and the alimentary tract takes place in nearly the same fashion as in the Echinoderms.
Observations on the structure and propagation of the genus Sagitta.
As Sagitta is hermaphrodite, there would appear to be no question of sex determination by any special chromatic element.
The most important of these are the Echinoderms, Brachiopods and Sagitta.
Observations on the Structure and Propagation of the genus Sagitta.
Name from Sagitta, an arrow, from the prevalent form of the leaves.
A brief account of a chromatin element resembling the accessory chromosome in Sagitta has been added for comparison.
In Sagitta it is known to be confined to the male germ-cells.