[62]

von Graff, Die Acoela, Leipzig, 1892. Appendix.

[63]

The development of the Acoela has been worked out recently by Mdlle. Pereyaslawzewa (Zapiski Novoross. Obshch. Odessa, 17 Bd. 1892) and Gardiner (Journal of Morphology, xi. No. 1, 1895, p. 155) with conflicting results. The former finds four endoderm cells, which give rise to a larval intestine. The Acoela are for her, Pseudacoela. Gardiner, on the other hand, finds no trace of an endoderm at any stage of the development of Polychoerus caudatus.

[64]

Tijdschr. Nederland. Dierk. Ver. Deel ii. 1875.

[65]

Von Graff, Monographie d. Turbellarien: I. Rhabdocoeliden, 1882. Gamble, Quart. Journ. Microscop. Science, vol. xxxiv. 1893, p. 433.

[66]

Zeitschr. f. wiss. Zoologie, Bd. lx. 1895, p. 163.