502 Ur. W. B. Carpenter on the Structure of Brachiopod Shells. 



XL VII I. — On the Minute Structure of certain Brachiopod Shells ; 

 and on Vegetable Cell-Formation. By William B, Car- 

 penter, M.D., F.R.S., F.G.S. 



To the Editors of the Annals of Natural History. 



Gentlemen, University Hall, London, May 19, 1856. 



Prof. King having introduced into his "Notes on Permian 

 Fossils," in the ' Annals ' for April last, certain comments upon 

 former statements made by me respecting the intimate structure 

 of the shells of Brachiopods, which must, if unnoticed, tend 

 to diminish the value attached to them by those who have hitherto 

 relied upon my assertions, I must beg you to admit the following 

 reply, which shall be as little personal as the tone taken by Prof. 

 King will permit me to make it. 



In the 'Annals^ for December 1843, I first published the 

 fact, which had been nearly a year ])reviously communicated to 

 the Royal Society, that the shells of many Brachiopods are tra- 

 versed by large perforations, passing from one surface to the other, 

 the external orifices of which may be detected as minute puncta- 

 tions ; and I mentioned that this character presents itself in all 

 the recent Terehratulm which I had examined, with the exception 

 of the T. psiltacea, which, as is now well known, has been since 

 separated as one of the two recent types of the genus Rhyncho- 

 nella. In the ' Reports of the British Association ' for 1844, I 

 entered much more fully into this point, embodying the results 

 of more extended examinations into the structure of the shells 

 of fossil Brachiopoda, and giving thirteen figures of the minute 

 organization of recent and fossil shells of this group, drawn 

 under magnifying powers varying from 75 to 250 diameters, by 

 that very accurate microscopic draughtsman, Mr. S. W. Leonard. 

 Save for a want of perfection in the printing- process, these 

 figures could scarcely be surpassed at the present time. 



In his ' Monograph of the Permian Fossils of England,' 

 published by the Palseontographical Society in 1850*, Prof. 

 King took upon himself, upon no other evidence than that of 

 the examination of the surfaces of various Brachiopods with a 

 Stanhope lens, to throw discredit upon my previous statements ; 

 asserting that punctures, though much more minute than those 

 in the Terebratulidce, occur in every species of Rhynchonella which 

 had passed under his notice ; and adding, " I doubt their absence 

 in any Brachiopod whatever." 



* I am obliged to call attention to this date, which I take from the 

 title-page, for a reason which will presently appear. The work was issued 

 as the publication of the Pal. Soc. for 1849 ; but (according to the practice 

 of the Society) it was not delivered to the members until the following 

 year. 



