DalL] 124 [February 15, 



at a recent meeting of the Society, it would seem desirable to cor- 

 rect some erroneous inferences contained therein, and still further 

 explain some disputed points from my own point of view. 



Mr. Morse seems to think that I have not acted impartially in 

 omitting to notice in my comparisons "nearly every point brought 

 forward to prove the Annelidan character of the Brachiopods" and 

 instances "the dorsal and ventral plates, the serial arrangement of 

 setae and gill laminae, the bilobed lophophore, the cephalic collar, the 

 thin and muscular visceral walls, the composition of the shell of Lin- 

 gular the cascal prolongations of the mantle, and the presence of 

 one or more pairs of segmental organs in form, character, and func- 

 tion like the segmental organs of the annelids." 



In regard to this, it was distinctly stated that in the comparisons 

 which I undertook, I included characters of high structural value 

 alone, such as are almost universally acknowledged to be so by the 

 naturalists of the present day, and not trivial characters peculiar to 

 small groups,, and due to adaptation and special development. This 

 is a general answer, and I believe a sufficient one to Mr. Morse's 

 criticisms, but I would add the following remarks to further explain 

 the circumstances. All the so-called Annelidan characters brought 

 forward by Mr. Morse in his published remarks on the subject, ap- 

 pear to me to be due to a series of extremely defective and entirely 

 unproved homologies, which require much more evidence than has 

 yet been brought forward, to confirm them. 



That dorsal and ventral plates, serial arrangement of setae and 

 gills (other than such as exist in Patella), and segmented organs of 

 any kind exist in the Brachiopods, remains to be proved; and as yet 

 no evidence has been brought forward to sustain any such hypothesis. 

 Such assertions must be supported by facts to render them worthy of 

 notice and none have yet been adduced. I submit that such a state- 

 ment as " one pair of segmental organs" in the absence of other seg- 

 ments with similar organs, is a contradiction in terms. Again, stria- 

 ted muscular fibre is not a characteristic of any group as distin- 

 guished from any other, according to Lebert, the best authority on 

 the subject, and is, moreover, present in all classes of Mollusks, ex- 

 cept the Cephalopod, where it may yet be found. 



Mr. Morse complains that I have accepted Clark's definition of the 

 Mollusca which includes the Tunicata, Polyzoa and Brachiopoda. If 

 Clark's definition includes them by their principal structural charac- 

 ters, as I believe it does, it remains for Mr. Morse to give us a defini- 



