DEVONIAN AND OLD RED PERIOD. 



145 



honeycomb. The most abundant species are Favosites Goth- 

 landica and F. hemispherica, both here figured, which form 

 masses sometimes not less than two or three feet in diameter. 

 Whilst Favosites has acquired a popular name by its honey- 

 combed appearance, the resemblance of Michelinia to a fossil- 

 ized wasp's nest with the comb exposed is hardly less strik- 

 ing, and has earned for it a similar recognition from the 



Fig. 84. Portion of a mass of Favo- 

 sites Goth la ndica, of the natural size. 

 Upper Silurian and Devonian of Europe 

 and America . (Original.) 



Fig. 85. Fragment of Favosites hemi- 

 apherica, of the natural size. Upper Silu- 

 rian and Devonian of America. (After 

 Billings.) 



non-scientific public. In addition to these, there are numer- 

 ous branching or plant-like Tabulate Corals, often of the most 

 graceful form, which are distinctive of the Devonian in all 

 parts of the world. 



The Echinoderms of the Devonian period call for little 

 special notice. Many of the Devonian limestones are " crin- 

 oidal ; " and the Crinoids are the most abundant and widely- 

 distributed representatives of their class in the deposits of 

 this period. 



The Cystideans, with doubtful exceptions, have not been 

 recognized in the Devonian ; and their place is taken by the 

 allied group of the " Pentremites, " which will be further spoken 

 of as occurring in the Carboniferous rocks. On the other hand, 

 the Star-fishes, Brittle-fishes, and Sea-urchins are all continued 

 by types more or less closely allied to those of the preceding 

 Upper Silurian. 



Of the remains of Ringed-worms (Annelides}, the most 

 numerous and the most interesting are the calcareous envelopes 

 of some small tube-inhabiting species. No one who has visited 

 the seaside can have failed to notice the little spiral tubes of 

 the existing Spirorbis growing attached to shells, or covering 



