37 



Species. 



19. S. pulvinata Smooth, like a cushion; rarely 



lobed. 



20. carbonaria Black and misshapen. 



21. incrustans Investing, with a thin crust. 



22. agaracina Compressed, lobed, reticulated; 



and externally covered with a 

 downy substance. 



23. cristata Flat, with erect and delicate ridges 



growing in the shape of cocks' 

 combs. 



24. domuncula Convex, smooth, slightly papil- 



lary, and very cellular. 



25. globosa Rounded, firm, and very caver- 



nous ; surface sprinkled with 

 smooth papillae. 



26. macida With white, crustaceous fibres, 



terminating in points. 



27. panicea Resembling, in its form, crum of 



bread ; and composed of bun- 

 dles of fine needle-like fibres, 

 crossing each other. 



28. papillaris Crustaceous, tender, and soft, 



with perforated papillae. 



29. urens Very brittle and soft, and inter- 



woven with very minute spines. 



30. acicularis White, solid, porous and scabrous 



externally; with fibres in fas- 

 ciculae converging to the centre. 



II. Subpediculated masses, contracted toward their base ; 

 simple or lobated. 



31. S. angulosa Sides angular ; various, unequal, 



and numerous foramina on the 

 edges of the angles. 



