380 APPENDIX. 



fundamental law, the common ancestor of all Zoophytes, namely, 

 the Protascus (vol. ii. pp. 129, 133). By the development of pores 

 in the wall of the stomach and of three-rayed calcareous spicules, 

 the Ascula changes iuto the Olynthus (Fig. 9.) In Fig. 9 a 

 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). 



Plate I. (Betioeen '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 a small 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 primteval 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 



