CARBONIFEROUS BRACHIOPODA. 
279 
interior characters of this remarl<;able Brachiopod has been published by Professor 
Winchell, Mr. Meek/ Dr. Carpenter,' Prof. King,'' Prof. J. Hall/ and myself/ and to 
their memoirs I would now briefly refer, so as to complete the description already 
given. 
In 1863, or a few years previously. Prof Winchell discovered in the Carboniferous 
Limestone, or " Burlington Limestone," of Burlington, Iowa, a shell indistinguishable in 
exterior appearance from our British examples of Martin's Anoviites cuspidatiis, and which, 
from presenting certain peculiar interior arrangements, had led him to propose for that 
and similarly constructed shells the generic name of Syringothyris. To his shell he gave 
the specific name of typa, but an attentive examination of his American type with true 
British examples of Sp. cuspidata led Prof. King to remark, at the conclusion of his able 
memoir already referred to, that " it may be safely assumed that Syrinyothyris cusjndata 
and /S*. typa are one and the same species," and that "it will necessarily follow that 
Martin's specific name, having priority, must be adopted in preference to the one pro- 
posed by Prof. Winchell." I entirely concur in the view taken in this matter by Prof. 
King, after having compared specimens of the American and British species. 
It will not be necessary to redescribe the exterior shape of Martin's shell, as it has 
been given at p. 44 of my Carboniferous Monograph, but I would merely remark that 
some British examples from Wetton, in Staffordshire, in my possession, have attained to 
four inches in breadth, with an enormous triangular area ; that a variety with finer and 
more numerous ribs has been met with by Mr. G. F. Whidborne in the Carboniferous 
Limestone Shale on the banks of the Avon, near Bristol, and that Mr. Robert Etheridge, 
junior, believes he has found the species in the Carboniferous Limestone of Scotland, 
but the three ventral valves in his possession are not sufficiently well preserved to admit 
of a positive identification. , 
Skell-strudure. — It is well known that the shell-tissue of many Palaeozoic Brachi- 
opoda has undergone changes during fossilisation, which have been caused by metamor- 
phism or mineralisation, so much so that, as noticed in his paper already quoted. 
Dr. Carpenter could detect not a vestige of perforations in some Irish specimens of 
Bp. ciispidata, while in others, as was clearly shown by himself and Professor W, King, 
canals or perforations, very minute and far apart, occurred indistinctly or in patches over 
the surface, and in some examples the shell was finely perforated all over its surface, the 
tubules not having been altered. 
It would therefore appear from Prof. King's and Dr. Carpenter's observations, which 
^ 'Proceedings of the Academy of Natural Sciences of Philadelphia,' December, 1867. 
2 " On the Shell-structure of Spirifera cuspidata and of certain allied Spiriferidee," ' Ann. and Mag. of 
Nat. Hist.,' July, 18G7. 
^ " Monograph of Spirifer cuspidatus and 'Ann. of Nat. Hist.,' ser. iv, vol. ii, 1868. 
* ' Palseontology of New York,' vol. iv, pp. 2.o2— 257, 1867. 
^ "Notes on some Perforated Palaeozoic SpiriferidBe," ' Geol. Mag.,' vol. iv, 1867. 
