7 
fundamental law, the common ancestor of all Zoophytes, namely, 
the Protascus (vol. ii. pp. 129,133). By the development of pores 
380 APPENDIX. 
in the wall of the stomach and of three-rayed calcareous spicules, 
the Ascula changes into the Olynthus (Fig. 9.) In Fig. 9a 
piece is cut out from the stomach-wall of the Olynthus in order 
to show the inside of the stomachal cavity, and the eggs which 
are forming on the surface (g). From the Olynthus the most 
various forms of Calcareous Sponges can develop. One of the 
most remarkable is the Ascometra (Fig. 10), a stock or colony 
from which different species, and in fact different generic forms, 
grow (on the left Olynthus, in the middle Nardorus, on the right 
Soleniscus, etc., etc.). Further details as to these most interest- 
ing forms, and their high importance for the Theory of Descent, 
may be found in my “Monograph of the Calcareous Sponges” 
(1872), especially in the first volume. (Compare vol. ii. pp. 160, 
167). . 
Pirate I. (Between pages 184 and 185, Vol. I.) 
History of the Life of the most Simple Organism, a Moneron 
(Protomyxa aurantiaca). Compare vol. i. p. 184, and vol. ii. p. 53. 
The plate is a smaller copy of the drawing in my ‘“ Monographie 
der Moneren” (Biologische Studien, 1 Heft, 1870; Taf. 1), of 
the developmental history of the Protomyxa aurantiaca; I have 
there also given a detailed description of this remarkable 
Moneron (p. 11-30). I discovered this most simple organism 
in January, 1867, during a stay in Lanzarote, one of the Canary 
Islands ; and moreover I found it either adhering to, or creeping 
about on the white calcareous shells of asmall Cephalopod (vol. ii. 
p-. 162), the Spirula Peronii, which float there in masses on the 
surface of the ocean, or are thrown up on the shore. The 
Protomyxa aurantiaca is distinguished from the other Monera 
by the beautiful and bright orange-red colour of its perfectly 
simple body, which consists merely of primeval slime, or 
protoplasm. The fully developed Moneron is represented in 
Figs. 11 and 12, very much enlarged. When it is hungry (Fig. 
11), there radiate from the surface of the globular corpuscule 
