DEVONIAN AND OLD RED PERIOD. 143 
ised wasp’s nest with the comb exposed is hardly less strik- 
ing, and has earned for it a similar recognition from the 
38 
once 
Oty 
ace 296%. 
2 
ane. 
rT} 8, 
CSA EES RS LS eee, 
Fig. 84.—Portion of amass of Favo- Fig. 85.—Fragment of Favosites hemi- 
sites Gothlandica, of the natural size. spherica, of the natural size. Upper Silu- 
Upper Silurian and Devonian of Europe rian-and Devonian of America. (After 
and America. (Original.) 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 LZchinoderms of the Devonian period call for little 
special notice. Many of the Devonian limestones are ‘crin- 
oidal ;” and the Crzmozds 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 
recognised 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-stars, 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 (Azwelides), the most numer- 
ous 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 Sfzrorbzs growing attached to shells, or covering 
the fronds of the commoner Sea-weeds (especially Fucus ser- 
ratus). ‘These tubes are inhabited by a small Annelide, and 
structures of a similar character occur not uncommonly from 
the Upper. Silurian upwards. In the Devonian rocks, Spir- 
orbis 1s an extremely common fossil, growing in hundreds 
attached to the outer surface of corals and shells, and appearing 
