JOURNAL OF MICROSCOPICAL SCIENCE. 



EXPLANATION OF PLATES VII, VIII, IX, & X, 



Illustrating the Notice of Professor Haeckel's recent additions 

 to the Gastrsea-Theory. 



PLilTE VII. 



In all the figures the Entoderm is coloured red, the Exoderm blue. The 

 food-yelk is mostly coloured red ; s, cleavage-cavity (blastoccel) ; a, cavity 

 of the primitive enteron ; o, blastopore (Urmund). 



Fig. 17. — Archigastrula of a Calcareous Sponge {Asculmis armata). After 

 Haeckel, ' Monographic der Kalkschwamme/ Taf. 18, fig. 6, 



EiG. 18. — Amphigastrula of a Calcareous Sponge {Si/cissa Huxleyi). After 

 Haeckel, ' Monog. d. Kalkschwamme,' Taf. 44, fig. 15. 



Fig. 19. Amphiblastula of a Calcareous Sponge {Sycandra raphanus). 

 After Oskar Schmidt (' Zeitschr. fur Wissen. Zool.,' Vol. xxv, Suppl., Taf. 

 9, fig. 5). The blastoccel or cleavage-cavity is by mistake marked with an 

 a instead of with s. o should be omitted. 



Fig. 20. — Archiblastula of a Coral (Actinia). After Kowalewsky (Russian 

 memoir on the ontogeny of the Coelenterata, Moscow, 1873, Plate iv, fig. 41). 



Fig. 21. — Archigastrula of the same Coral (Ibid., Plate iv, fig. 2). 



Fig. 22. — Archigastrula of a Medusa (Pelagia). After Kowalewsky (Ibid., 

 Plate iii, tig. 2). 



Fig. 23. — Archigastrula of a Worm (Sagitta). After Kowalewsky ('Em- 

 bryologische Studien an Wurmen und Arthropoden,' Petersburg, 1871. 

 Taf. 1, fig. 2). 



Fig. 24. — Amphiblastula of a Worm (Euaxes). After Kowalewsky (Ibid., 

 Taf. iv, fig. 27). 



Fig. 25. — Archigastrula of a Brachiopod (Argiope). After Kowalewsky 

 (Russian memoir on the ontogeny of the Bracliiopods, Moscow, 1874, 

 Plate i, fig. 8). 



Fig. 26. — Amphiblastula of a Mussel (Unio). After an unpublished 

 drawing of Carl Rabl. 



Fig. 27. — Amphiblastula of the same Mussel in a later stage. After 

 Carl Rabl. 



Fig. 28. — Amphigastrula of the same Mussel. After Carl Rabl. On the 

 left side is seen a large mesoderm-cell. 



Fig. 29.— Archiblastula of a Snail (Limnseus). After Carl Rabl ("Die 

 Ontogenie der Siisswasser," Pulmonaten ' Jenaische Zeitschrift fiir Na- 

 turw,' 1875, Vol. ix, Taf. vii, fig. 9). 



Fig. 30. — Archiblastula invaginata of the same Snail. After Carl Rabl 

 (Ibid., Taf. vii, fig. 10). 



