206 RAMBLES AND REVERIES. 



found in two parts, the head by itself and the body 

 and tail joined together. (Fig. 55.) In the case of 

 Calymene the ringed thorax is often met with by 

 itself, while not unfrequently the rings are separated 

 from one another. 



The month of trilobites, by the simplicity of its 

 structure and the absence of antennas, warrants the 

 inference that these creatures were "bottom-feeders," 

 that is, they fed from the ground. Mr. Salter, 

 who made trilobites his special study, arrived at 

 the opinion that they lived in the mud and even 

 found their food in the organisms which it con- 

 tained, very much after the manner in which the 

 earthworm derives its nutriment from the soil. 

 They could, however, swim, and probably were not 

 averse to making a meal off any dainty mollusc that 

 might come in their way. 



No traces of legs have been found, save those 

 very indefinite structures already referred to, but 

 it is supposed that they had fleshy or cartilaginous 

 feet, like the footstalk of the Lingula, and which of 

 course has left no fossilised remains. It is certain 

 too that some species could coil themselves up like 

 the wood-louse ; others, as the Homalonotus, were 

 probably not able thus to protect themselves against 

 their foes. 



But the most remarkable feature in the morphology 

 of the trilobite was the eye (Fig. 56) ; this varies 

 with the species. In Homalonotus it is small and 

 protuberant like that of the lobster. The eye of 

 the Bumastus Barriensis, a common fossil of the 

 Woolhope beds, ^ems to have been protected with 



