. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Mr. E. H. L. Schwarz on Coccoliths. 343 lith) transforming itself into a cyatholith (reproductive stage); the granular ring, which I have not observed in my fossil forms, being protoplasmic, and the outer ring the commence- ment of one of the cups. Still following Hseckel, we see that the internal discolith then divides (fig. 5), and traces of the. Figs. 1-7.—After Hseckel. 1. Incomplete form. 2. Fully formed disco- lith. '3. One with the granular ring. 4. Commencing cyatho- l
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Mr. E. H. L. Schwarz on Coccoliths. 343 lith) transforming itself into a cyatholith (reproductive stage); the granular ring, which I have not observed in my fossil forms, being protoplasmic, and the outer ring the commence- ment of one of the cups. Still following Hseckel, we see that the internal discolith then divides (fig. 5), and traces of the. Figs. 1-7.—After Hseckel. 1. Incomplete form. 2. Fully formed disco- lith. '3. One with the granular ring. 4. Commencing cyatho- lith : a, outer ring; b, granular ring; c, mark-ring; e, Mark- feld; d, central point. 5. One with dividing discolith and portion of the larger cup forming. 6, 7. Cyatholiths. Figs. 8, 9.—Coccolithns oceanicm, the mature form (discolith). Fig. 10.—Young discoliths just released from the cyatholith (cocco- sphere). Figs. 11, 12.—Two positions of the fully formed cyatholith. Figs. 13-15.—Cyatholith with the rim broken off. Fig. 16.—Diagrammatic section through a cyatholith. Figs. 17-21.—Successive stages in the division of the discolith. Figs. 22-26.—A cyatholith containing four discoliths, which was turned over and then dissolved with acetic acid, setting the contents free, which were then moved about. Fig. 27.—Nodosaria calomorpha, Reuss, associated with coccoliths in the clay containing Schlotheimia angulata (Schl.). second, larger cup appear ; the two cups are then completed, and the dividing discolith is shut in between them the smaller cup forming a lid to the cavity of the larger (figs. 11 12, 16). In the early stages of division the form is still oval (figs. 17, 18), but soon the cups become rounded, and the divisions go on irregularly till there are sixteen or more embryonic discoliths ; intermediate forms with four, five six seven, &c. are frequent. In the later stages the cups of the cyatholith become brown and opaque, and finally, failing to adher
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