350 GENERAL SUMMARY TO 



Articulata, Huxley, 'Int. Class. An.,' p. 116, 1869. 



" The intestine ends in a blind sac " (1. c., p. 116). 

 Arthropomata, Gill, ' Arr. Earn. Moll./ p. 25, 1871. Dall, 'Am. Journ. Conch., 



vol. vii, p. 60, 1871. 

 Clistenterata, King, 'Ann. and Mag. of Nat. ' (4), vol. xii, p. 15, 1873. 

 Gill ends by suggesting that, if we follow the rules of priority, Owen's names should 

 be adopted ; and that Bronn's, based on intestinal characters, might well be taken if 

 Owen's were superseded ; but I have made use of those proposed by Prof. King, believing 

 them to be more appropriate. 



In the General Introduction to this work I detailed what had been done up to 1853, 

 with respect to the classification of the various families and genera constituting the class ; 

 and, although a very great advance has been effected in our knowledge during the thirty 

 years since that time, it is not yet possible to offer an entirely satisfactory or permanent 

 classification. This is chiefly due to the large number of so-termed genera that have been 

 proposed without a sufficiently critical comparison with those already in use, so that much 

 confusion has occasionally ensued; and it is not easy to deal satisfactorily with upwards 

 of two hundred so-termed genera and more than five or six thousand species, named 

 varieties, and dubious synonyms. 



Any scheme of classification must therefore be to a certain extent considered as pro- 

 visional, the difficulty of arriving at a completely satisfactory arrangement of the Brachio- 

 poda being far greater than those not initiated in the subject can possibly be aware of. 

 It is most desirable to seek simplicity as far as the subject will permit, for the Brachio- 

 poda, as will be shown in the sequel, have played a very important part in the great life- 

 system of our globe from nearly its first dawn up to the present time. 



A tendency has unfortunately been manifested during the last few years to elevate into 

 generic importance characters that are, I fear, of only secondary or specific value, and 

 thus increase the number of so-termed genera to an unnecessary extent. 



As already stated, it will be necessary to admit the two great divisions Lyopomata or 

 Tretenterata, and Arthropomata or Clistenterata, into any scheme of classification. 



Dr. Waagen observes at page 447 of his work on the Carboniferous Brachiopoda of 

 the Salt Range (' Palseontologia Indica,' 1883), that " During the progress of the investi- 

 gation bearing upon the description of the Brachiopoda of the Salt Range it has become 

 absolutely necessary to create some larger subdivisions of the Brachiopoda, as the simple 

 divisions into Arthropomata and Lyopomata appear to be quite insufficient to bring out 

 clearly the relations of the different groups. I therefore propose to distinguish three sub- 

 orders of the Arthropomata, for which I wish to introduce the following designations : 



" i. Sub-Order Kampylopeymata, sive Terebratulacea, including the families Terebratu- 

 lidce, Thecideida, Strinyocephalida, and Bhynchonellidcs. ii. Sub-Order Ilelicopeymata, 

 sive Spiriferacea, comprising the families Atrypidce, Nucleospirida, Athyrida, and Spiri- 



