In the presence of three lenses the eye of Sagittaapproaches in some respects the eye of the Arthropoda.
In Sagitta the history of the generative cells, which was first worked out by Kowalevsky and Buetschli, has been recently treated with great detail by O.
The paired cephalic eyes of Sagitta are spherical bodies imbedded in the epidermis.
The class of the chaetogatha, which is only represented by the cognate genera of Sagitta and Spadella, is in another respect also a most remarkable branch of the extensive vermalia stem.
Thus we have in Sagitta a perfectly clear and simple illustration of the original coelomation of the enterocoela.
This palingenetic fact is the more important, as the greater part of the two body-cavities in Sagitta changes afterwards into sexual glands--the fore or female part into a pair of ovaries, and the hind or male part into a pair of testicles.
Coelomula ofsagitta (gastrula with a couple of coelom-pouches.
The same kind of coelom-formation as in sagitta was afterwards found by Kowalevsky in brachiopods and other invertebrates, and in the lowest vertebrate--the amphioxus.
On the one hand, the transparency of the body and the embryo, and, on the other hand, the typical simplicity of its embryonic development, make the sagitta a most instructive object in connection with various problems.
The spherical blastula that arises from the impregnated ovum of the sagitta is converted by a folding at one pole into a typical archigastrula, entirely similar to that of the Monoxenia which I described (Chapter 1.
And glad am I that we are past it, and come once unto the day, to those other words of the prophet, "A sagitta volante in die.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "sagitta" in a variety of sentences. We hope that you will now be able to make sentences using this word.
