200 , RAMBLES AND REVERIES. 



structure, and affinities of the objects concerned. 

 For a long time naturalists were quite undecided as 

 to the precise position which on these grounds ought 

 to be accorded to the trilobite, owing to the fact 

 that they knew next to nothing concerning its 

 structure. It seemed so utterly different from every 

 creature now known, and furnished so little of 

 suggestion in its necessarily defective fossilised form 

 that it was only recently that anything like a final 

 and authoritative opinion was arrived at as to its 

 true position in the animal kingdom. The very 

 names of the more familiar genera show how ready 

 the earlier naturalists were to confess their ignorance 

 in regard to these singular fossils. Calymene, the 

 hidden, Agnostusi the unknown, Asapkus, the un- 

 certain, Paradoxides, etc., all reflect the attitude of 

 mind of those who were first called upon to deal 

 with these perplexing creatures. As to their general 

 Crustacean characters there has been but little doubt 

 since the time of Brongniart, and their partial re- 

 semblance to the Isopoda (or wood-lice) as well as to 

 Limulm (or king-crab) is now definitely agreed upon. 

 Even a superficial comparison between the fossil 

 king-crab shown at Fig. 57 and a typical trilobite will 

 demonstrate the accuracy of this conclusion, and 

 when we come to compare the larval forms of the 

 two creatures this will be made still more clear. In 

 Haeckel's Systematic Survey trilobites are placed 

 amongst the Branchiopoda or " gill-footed" crus- 

 taceans, and so are regarded by him as relatives of the 

 water-fleas. But as no traces of breathing organs, 

 either aquatic or aerial, nor any vestiges of feet have 



