iG PROF. P. M. DUNCAN ON CYATHOPHYLLUM FLETCHERI. 
considerable relative size, besides a vesicular endotheca near the 
wall between the septa. 
Under these circumstances there is no reason for altering the 
classificatory position in which I placed these corals in 1867. 
Norte, January 1884.—Immediately after this communication was 
read I received Lindstrém’s interesting paper on the Operculum- 
bearing Corals read before the Swedish Academy, Sept. 13,1882. It 
required very careful consideration. Later on I received Lindstrém’s 
Index to the generic names applied to the Corals of the Paleozoic 
Formation, and as it contained a statement in relation to Palcocyclus 
which required investigation, it necessitated further delay. 
In the first-mentioned essay there is a list of synonyms of one of 
the Paleocych, my Cyathophyllum Fletcheri, Kd. & H., sp., which 
shows that no less than thirteen genera &c. may be associated with 
it, and that it may have twenty-two specitic titles!! Since I wrote 
on the necessity of placing Paleocyclusin Cyathophyllum, the genus 
has been called Campophyllum, Haliophyllum, Pholidophyllum, 
Acanthocenium, Taeniocyathus, Acanthocyclus, and even Acanthodes. 
Seven authors have worked at the form, one of whom has given it 
five specific and two generic names, and another six specific names, 
still keeping it in the genus Cyathophyllum. At least this is accord- 
ing to Lindstrom’s synonymy*. TI find that I am said to have 
named this form Cyathophyllum Lovent and Petraia bina in the 
same year in which the Kssay on the Paleocycli was published in 
the Philosophical Transactions ! ! 
What Lindstrom must mean, so far as I am concerned, is that I 
placed Patraia bina amongst the Corals described in ‘ Siluria,’ and 
also Cyathophyllum Lovent. He considers those forms to be the 
same as Palwocyclus Fletcher, Kd. & H.,= Cyathophyllum Fletcheri, 
Kd. & H., sp. 
I demur very decidedly against the identity of Cyathophyllum 
Loven and C. Fletchert; and as I never attempted to predicate 
what a cast might turn out to be, I object to the synonymy of 
Petraia bina and the last-named species. 
On comparing the morphology of Cyathophyllum (= Palcocyclus) 
Fletchert and rugosum, as described in the Philosophical Transactions, 
I do not see any definite difference between it and that given by 
Lindstrom, so far as the internal structures are concerned. What 
I have termed variolar endotheca, Lindstrom terms ‘“ like-formed,” 
“uniform” stereoplasma. J have always considered the compa- 
ratively new term “stereoplasma” to be something in addition 
to ordinary endotheca, a filling-up stuff or a substance environing 
epitheca. But I hold to the old term in this particular. 
The outside of the coral, however, has yielded to Lindstrém very 
remarkable structures, not a trace of which have I ever seen in English 
specmens. Lindstrom states in his description that the cost are 
* “Om de paleozoiska formationernas Operkelbarande Koraller,” K.-Syensk. 
Vet. Akad. Handl. Band vii. no. 41, p. 64. 
