Suppose we have selected one of the numerous subsidiary problems suggested by the general inquiry, and obtained such full and complete information about one particular industry that we of a can tabulate the wages of the workers for a long series of years.
Of royal codes, and even more so if we were able to tabulate the indirect evidence as to legal rules.
Corals, both reef-builders and others, flourished in the clearer waters; rugose forms are represented by Amplexoid, Zaphrentid and Cyathophyllid types, and by Lithostrotion and Phillipsastraea; common tabulate forms are Chaetetes, Chladochonus, Michelinia, &c. Amongst the echinoderms crinoids were the most numerous individually, dense submarine thickets of the long-stemmed kinds appear to have flourished in many places where their remains consolidated into thick beds of rock; prominent genera are Cyathocrinus, Woodocrinus, Actinocrinus; sea-urchins, Archaeocidaris, Palaeechinus, &c., were present; while the curious extinct Blastoids, which included the groups of Pentremitidae and Codasteridae, attained their maximum development.
Nicholson, Palaeozoic Tabulate Corals (Edinburgh, 1879); M.M.
We may tabulate the facts as to head-structure in Chaetopoda and Arthropoda as follows: Grade x (below the Arthropoda).