348 Mr. J. Ralfs on the Mode of Growth in Calothrix, §c. 
Fig. 3. The branched chambers of Cliona celata exposed by the removal of 
the surface of the matrix: a, papillary punctures, 
— 4. Spicula of C.celata much enlarged. 
— 5. C. spinosa as seen through the transparent matrix, magnified two 
times. iS 
— 6. A portion of the surface of the matrix exhibiting the papillary pune- 
tures :—natural size. 
— 7. Spicula of C. spinosa much enlarged. 
— 8. Triradiate spicula from the surface of Thoosa bulbosa? 
Pirate XIV. 
Fig. 1. Chambers of C. gorgonioides exposed by the removal of the surface 
of the matrix, a little enlarged: a, papillary punctures, 
2. C. Fryeri as seen through the transparent matrix; one half en- 
larged. 
— 3. Surface of the matrix of the same, exhibiting the papillary punctures. 
4, A series exhibiting the development of C. Fryeri considerably en- 
larged : a, represents the first stage; 6, c, d, e, f, the succeeding 
stages. 
— 5. Spicula of C. Northumbrica much enlarged. 
— 6. Ditto  C. gorgonioides ditto. 
— 7. Ditto © C. gracilis ditto. 
— 8 Ditto C. Howsei ditto. 
— 9. Ditto C. Fryeri ditto. 
— 10. Ditto C. Canadensis ditto. 
Puate XV. 
Fig. 1. Chambers of C. corallinoides exposed by the removal of the surface 
of the matrix: a, papillary punctures. 
— 2. Spicula of C. corallinoides much enlarged. 
— 3 Ditto C. radiata ditto. - 
— 4. Ditto C. dendritica ditto. 
— 5. Ditto C. insidiosa ditto. 
— 6. Ditto C. quadrata ditto. 
— 7. Ditto C. labyrinthica ditto. 
— 8. Ditto C. cervina ditto. 
a 9... Ditto .. C. Araers ditto. 
— 10. Ditto C. nodosa ditto. 
— 11. Ditto C. muscoides ditto. 
— 12. Ditto C. vastifica ditto. 
— 13. Ditto C. angulata ditto. 
~ 
XXXVII.—On the Mode of Growth in Calothrix and allied 
Genera. By Joun Ratrs, M.R.C.S., Penzance*. 
In my former communication I remarked that in Oscillatoria the 
division of the filament is accompanied by that of its sheath, 
whilst in Microcoleus the sheath is so inflated as not to interfere 
with the process of division. I shall now endeavour to prove 
that the appositional branches in Calothriz and other genera are 
the results of modifications of that mode of division which we see 
in Oscillatoria and Microcoleus. 
* Read before the Botanical Society of Edinburgh, 8th March, 1849. 
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