JOURNAL OF MICROSCOPICAL SCIENCE. 



DESCRIPTION OF PLATE II, 



Illustrating Dr. J. Braxton Hicks's paper on the Develop- 

 ment of the Gonidia of Lichens, in relation to the 

 Unicellular Algae. 



Fig. 

 1, — Gonidia, becoming surrounded by the fibre. 



2. — „ segmenting, and proceeding to form " Soridia." 



3. — A Soridium submitted to pressure. 



4.— „ opened, in which the Glaocapsa-ch&nge is first commencing. 



5. — Two Soridia; (a) two mother cells in one mucous envelope (b) issu- 

 ing from them. 



6. — Another form of the Glaocapsa-cha.nge. 



If. — Two unchanged Gonidia, with Glaocapsa-cells in the binary plan of 

 segmentation. 



8. — Mass of Cladonia-Glseocapsa, in which many varieties of segmentation 

 are shown cotemporaneously : («), simplest result of segmentation ; 

 {b, b, b), globular mother cells ; (c), oval mother cells ; {d, d), smaller 

 (younger 'i) mother cells. 



g.^(«), Group of oval mother cells, inclosed in a common mucous layer; 

 (b, b), smaller mother cells in various conditions; (r), results of 

 breaking up of mother cells. 



10. — Cladonia-GlcEOcapsa, showing the quarternary form of subdivision- 

 segments yet without separate sheath of mucus. 



11. — Mass of Cladonia-Glceocapsa, in which a great variety of forms 

 are shown -.{a, a), resembling Uamatococcus rupestris, Hass. {Glmo- 

 capsa polydermatica, Kiitz.) ; {b^ b), mother cells of large size, each 

 in separate single envelope ; (c, c), small mother cells, having two or 

 three mucous sheaths. 



12. — Uchen-Palmoglcea. Mucous envelope dense, and of a purple colour. The 

 layer surrounding each cell at first purple, as at a ; afterwards that 

 colour is confined to the exterior. 



13. — {a^ h^ c), Various state of same after immersion in water. 



14. — Mass of Lichen-Palmofflcea, after dissolution of the purple mucous 



sheath: («), Glteocapsa polydermatica, Kiitz.; (b), Falmoglcpci ; 



(c, c), fibres of the original Soridium, now more delicate, dipping 



between the subdivisions. 



15. — Increase of diameter of mucous layer, and decrease of that of cell, by 



frequent division, the effect of humidity. 

 16. — Changes in the same direction, like Hamatococcus minutissimus (Hass.). 



17,_Mass of Falmogldsa, Glaocapsa, and other kindred forms, derived from 

 Cladonia- Gonidia ; («, a, a), the fibres now very delicate. 



18. — Portion of mass produced by the alteration of .the gonidial layer of the 

 mature Lichen {Cladonia). 



