THE PRE-ADAMITE EARTH, 



table kingdoms were called successively into existence, permitted 

 successively to live, and were destroyed successively before any 

 vertebrate animals superior to fishes existed, and even these were 

 limited to the Placoid and Ganoid orders. No land animals had yet 

 appeared. Reptiles made their first appearance in the fourth 

 period, where they were represented, however, only by a single 

 genus ; and even in the*fifth and last period, no more than two 

 genera existed, one of which had been revived from the preceding 

 period. During the entire age, not more than sixty- seven 

 genera of fishes existed, and two of reptiles. Of the superior 

 orders of birds and mammifers none were yet created. 



296. The animal forms which most abounded were those of 

 Tentaculiferous Cephalopods, Marine Gastropods, and Lamelli- 

 branchia, Brachiopods, Bryozoa, Echinodermata, and Polyparia, 

 commonly known as zoophytes. Of the divisions of Annulata in 

 this age but little is known, owing, no doubt, to the perishable 

 nature of their structure. One family, however, of Crustacea, 

 Trilobites, appeared during the first and succeeding periods in 

 such numbers, as to confer upon the epochs a distinct organic 

 character. These fossils have been long known in England under 

 the local and erroneous name of Dudley insects or locusts, from 

 their having been found in that district in such immense numbers. 

 This remarkable family of Crustaceans did not survive the fourth 

 Palaeozoic or Carboniferous period, their principal development 

 being in the Silurian and Devonian periods, which literally teemed 

 with them. These crustaceans have no existing type, that which 

 most resembles them being the Bopyrus, a small parasitical 

 animal which attaches itself to the prawn, causing a large swelling 

 in its body. 



297. The fossil trilobites are generally from one to six inches 

 in length, attaining, nevertheless, in exceptional cases to two 

 feet. They were protected by a crustaceous shell or case, com- 

 posed of annular segments, jointed one upon the other like those 

 of the lobster's tail. This testaceous covering seems to have had 

 a contractile power like that of the armadillo, since the animal is 

 sometimes found more or less expanded, and sometimes coiled up. 

 Owing to the absence of all traces of antennae or feet, it is sup- 

 posed that these animals adhered to rocks like fuci, or collected 

 together in masses, forming conglomerations. Some naturalists, 

 however, assume that they had locomotive power in water, either 

 by soft paddles which have disappeared, or by skulling forward 

 by means of the flexible extremity of their bodies. From the 

 peculiar structure of the mouth it has been inferred that they 

 were carnivorous, preying on naked mollusca or annulata, with 

 which their remains are sometimes associated. 



56 



