28 Mr. T. Davidson on Recent Terebratulse. 



the marine testaceous Mollusca of the North-east Atlantic and 

 neighbouring seas, by Robert M'Andrew, in 1856, wherein 

 every requisite information in connexion with the habitats of 

 nine species of Brachiopoda have been carefully registered. 



The question relating to the intimate shell-structure has been 

 admirably elaborated by Dr. Carpenter. In 1853 he treated the 

 subject in the second chapter of my ' General Introduction/ as 

 well as in several subsequent papers in the ' Annals ' and in the 

 'Proceedings of the Royal Society^; while Dr. Gratiolet and 

 M. S. Cloez have also given us some little additional informa- 

 tion, which will be found recorded in the memoirs already 

 quoted. 



We now arrive at the difficult question that relates to classi- 

 fication ; and here I must humbly admit (nor need feel ashamed 

 to confess it) that, although my own feeble efibrts have for years 

 been strenuously bent in that direction, and although many have 

 been the observations that have been made and recorded both by 

 myself and others, I am not yet entirely satisfied as to the per- 

 fect stability of our building. That we have proceeded in the 

 right direction, there can exist, I think, but little doubt. It 

 was necessary and unavoidable at first to divide and subdivide 

 our groups, in order to be able to study and appreciate their 

 characters more conveniently and accurately, as well as to ex- 

 tricate the species from the chaos in which they were involved 

 by grouping them according to their resemblances and affinities ; 

 but the time will no doubt come when, masters of our subject 

 from a hard-earned experience, we may put into action our 

 philosophical tendencies, which will enable us to compare and 

 value the analogies, so as to reunite or draw closer together those 

 links which had for a time been necessarily parted. 



The object and limits prescribed to the present communication 

 will not, unfortunately, admit of my indulging in a review of 

 the whole subject of classification, as I should have desii'ed, or 

 in a criticism of the many so-termed genera that have been 

 fabricated since 1852. Some are, no doubt, good; but the 

 lai'ger number rest on what has appeared to me a very uncer- 

 tain foundation, and are probably destined to an ephemeral exist- 

 ence. I will therefore content myself with casting a rapid glance 

 at some of the divisions introduced among the recent Terebra- 

 tulidce, and am happy to observe that, with the exception of 

 Gwyyiia and Macandrevia, King*, whose generic claims do not 

 appear to me substantiated, and the abandonment of Waltonia 

 by myself in 1853, very little innovation in this respect has 

 taken place since the publication of my ' Sketch' in 1852, and 



* Proceedings of the Dubliu University Zool. and Bot. Assoc, vol. i. 

 part 3, 18.59. 



