lxxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1895, 



the air-breathing scorpions were derived from a still earlier and 

 as yet undiscovered aquatic jirogenitor, possibly in Cambrian or pre- 

 Cambrian times. 



Simultaneously with the commencement of my own work on the 

 Merostomata, J. W. Salter undertook a monograph on the British 

 Trilobites for the Palseontographical Society in 1864, of which four 

 parts appeared — from 1864-1867. This work occupies 224 pages 

 of letterpress, illustrated by 31 quarto plates, and contains descrip- 

 tions of 114 British species (leaving about 200 more to be described). 

 No one who takes up this fine work of our old friend can avoid a 

 feeling of regret that Salter's valuable life and splendid palseonto- 

 logical knowledge should not have been longer spared to us to carry 

 on to its completion this most important service. 



One cannot help also imagining the joy with which so enthu- 

 siastic and earnest a worker as Salter would have welcomed and 

 revelled in the recent discoveries of the long-sought appendages of 

 the trilobites, which, alas ! he did not live to see. 



In 1864 he observed : — ' Every author who has written on 

 trilobites has more or less perceived their analogy with the 

 Limulus or King-crab, to which tribe there is, indeed, a good deal 

 of external resemblance. But this resemblance totally fails when 

 we examine the under side of the animal ; for all the researches 

 hitherto made (and they are many) fail to detect the slightest traces 



of limbs in the trilobite.' ' It is impossible, seeing the state 



of preservation in which they occur, to suppose that in every case — 

 in fine shale, in limestone, in arenaceous mud — all traces of tbese 

 organs should have been lost, had they ever existed. We are 

 compelled to conclude that trilobites had not even membranaceous 

 feet, and that the ventral surface was destitute of appendages.' 

 (Op. cit. p. 9.) Fortunately, these long-sought organs have now 

 been discovered. 



Following up the progress of our knowledge of the trilobites, I 

 may note that Dr. Henry Hicks made his first communication to this 

 Society in 1865 on the genus Anopolenus, and between 1871 (when 

 he came to London from the happy hunting-grounds of St. David's 

 and joined the Geological Society) and 1876, he communicated to 

 this Society a series of papers on the faunas of the ' Menevian,' the 

 Lingula Flags, Tremadoc Slates, and Arenig series, giving descrip- 

 tions of no fewer tban 34 species of trilobites, belonging to 18 

 genera, from those ancient rocks. 



