THE CULT OF THE TRILOBITES 



By GRENVILLE A. J. COLE, D.Sc. F.R.S.. 



Professor of Geology in the College of Science for Ireland 



Trilobites, originally called trinuclei, are among the oldest 

 extinct animals described from the British Isles. Edward 

 Lhuyd (or Lhwyd) drew attention to them in 1699, in his work 

 on the fossils under his care in the Ashmolean Museum, Oxford 

 {Lithophylacii Britannici Ichnographia). To him, such forms 

 were moulded picturesquely in the rocks, by some process of 

 natural fertility ; their imperfections were due to their cramped 

 surroundings, and it was impossible to believe that they ever 

 were endowed with life. Even when organised fossils, as dis- 

 tinct from mineral fossils — that is, minerals dug out of the earth 

 — became accepted as records of long-lost faunas and floras of 

 the globe, each genus was regarded as an independent outcome 

 of the Creative Mind, and the palaeontologist was not encour- 

 aged to indulge in doctrines of descent. When, however, it 

 became possible to trace out an evolutionary sequence, here 

 yielding an orderly procession, here, per saltmn, introducing 

 a delightful element of surprise, the details of genera and species 

 became far more than a dull matter of description. The 

 succession of the trilobites became linked with that of the crabs 

 and lobsters, or perhaps the insects, of our modern times, and 

 the search for ancestral trilobites led to an inquiry into the 

 origin of the arthropods as a whole. 



The trilobites were generally recognised as crustaceans. 

 They are unknown outside the Palaeozoic, the " old life," era ; 

 but that implies a long enough existence on the globe. In the 

 earliest Cambrian strata a considerable variety of forms occurs, 

 and one species is as much as six inches long. Other con- 

 temporaneous Crustacea, the phyllocarids, were probably a 

 shade higher in the scale of life ; but the trilobites surpassed 

 them in abundance, dignity, and size. In the Cambrian seas 

 they met with no more formidable rivals than carnivorous 

 worms. Paradoxides of the British Middle Cambrian is often 

 more than a foot (30 cm.) long. The trilobites were not ade- 

 quately armed ; they probably went down quickly before the 

 clawed and powerfully jawed eurypterids and the shark-like 

 fishes of late Silurian and Devonian times ; but for long ages 



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