﻿T. Davidson — What is a Brachiopod ? 265 



announced so positively, from the history of the American Brachio- 

 poda alone, the vermiform affinities of the Brachiopods now so con- 

 clusively proved by the development of Argiope in Kowalevsky's 

 paper." 



No one can doubt that the Brachiopods and Amphitrites possess 

 many important characters in common after perusing the admirable 

 observations upon the subject contained in Prof. Morse's memoir ; 

 but, at the same time, as was remarked to me by Prof. Verrill, 

 almost any invertebrate group may be annelidelized by overrating 

 certain points of its aflSnities ; and, it seems to me, that one must not 

 place entire confidence in any classification whicb is founded to so 

 great an extent on embryological chai'acters. It may turn out, how- 

 ever, that the Brachiopoda really constitute a division of the Annelids. 

 The setee do not appear to be a constant character, and the tendinous 

 peduncle of the Terebratulidas^ seems very different from the annu- 

 lated structure which Morse describes in Lingula, and it appears-, 

 according to Dr. J. Gwyn Jeffreys, to closely resemble the peduncle 

 of a species of Anomia (A. patelliformis) , Lingula being likewise an 

 aberrant form. 



Morse does not, however, fail to observe that " in considering the 

 assemblage of remarkable characters in the Brachiopoda, we must 

 recognize in them a truly ancient type. Thus, while we do not find 

 them in all their characters resembling any group of worms, I have 

 endeavoured to show that all their features, to a greater or lesser 

 degree, are shared by one or other of the various groups of the 

 Vermes, with one or two features of the Arthropods." 



Morse concludes his elaboi'ate series of observations by stating 

 that he must regard the Brachiopoda as ancient cepJialized Choetopods, 

 while Serpula, Amphitrite, Sabella, Fvotula, and others, may be 

 regarded as modern (later) ceplialized Choetopods. 



Mr. Dall, a distinguished American naturalist, is strongly opposed 

 to the idea of jjlacing the Brachiopoda among the Annelids, and in 

 order that the reader may become acquainted with both sides of the 

 question, we must refer him to Ball's paper in the American Journal 

 of IScience for 1871. Therein he maintains, after a lengthened com- 

 parison between the Annelids and Brachiopoda, that these last are 

 allied to the other groups included in the MoUuscoida, and through 

 their combined characters to the typical Mollusca. Stoliczka agrees 

 with the conclusions advocated by Dall, and adds, "There cannot 

 be, I think, much doubt as to the true Molluscous character of the 

 Brachiopoda, and their proper classification between the Anomiidcs 

 of the Pelecypoda, and the Saccopoda, and the arm-bearing section 

 of the Ciliopoda." ^ 



With such contradictory views as have here been briefly announced, 

 it seems still premature to emit a positive opinion with respect to 

 the affinities of the Brachiopoda, notwithstanding the mass of most 

 valuable information so ably contributed to science by Morse, 

 Kowalevsky, Dall, and others. The following observations on the 



1 Palseontologia Indica, Brachiopoda, toI. it. 1872. 



