264 PROCEEDINGS OF THE 



are not rounded in the better preserved specimens, and that they 

 are, in fact, only the fractured bases of the spines or booklets." 

 To Mr De Wilde's statement, wliere he says, "supposing the 

 articulation to be a mistake, these fragile appendages would hardly 

 break invariably at that point where they are stoutest and 

 strongest," I replied, that " he must remember that although this 

 be their thickest part, yet it is their weakest point in their 

 relation to the stem," stating, as points in illustration, "that 

 twigs torn from the stem of a plant naturally break close to their 

 attachment to the stem, yet this is also their thickest point; and 

 that the spines of the I'rodudce found in our soft shales are seen 

 in most cases to be fractured close to their attachment to the 

 shell, owing to the pressure they have sustained;" and further 

 stated, " that this fracturing of the spines by pressure was not 

 always regular in its distance from the organism, either in the 

 Produdce or the coral in question, as some of my specimens in the 

 hands of Mr Woodward clearly showed." 



Dr Duncan, in his reply to some of my remarks, says, that 

 " really the slightest possible examination of the specimens proves 

 that the appearance of irregular fracture of the sjiines is the 

 exception, and that which I have described is the rule. The 

 irregular fracture has been produced by pressure, which has acted 

 more upon the base of the tubercles than upon the junction of the 

 booklets with the tubercles. Probably some anchylosis had oc- 

 curred, and the joint had been destroyed." 



Dr Duncan, in his further remarks, does not advance a single 

 fact beyond what I have already quoted, either for considering 

 the above corals as two distinct species, or in support of the 

 so-called articulation of the booklets. He says, " I am content to 

 abide by the decision I came to whilst the Heterophyllia in the 

 Hunterian Museum of Glasgow Avere still called Serjmlce, and to 

 consider R. LyeUi and H. mirabilis very interestingly separate 

 species." The rest of his note consists of a personal attack upon 

 myself for venturing to criticise his (Dr Duncan's) work. To his 

 personal remarks I thought it unworthy to reply in my concluding 

 note in the Magazine, except in stating, " that my ol)ject was to 

 try and settle the determination of the coral in question, not the 

 qualifications of palaeontologists." To his assertion, that irregular 

 fracture of the spines is the exception and not the rule, and the 



