Young — On the Genus Ileterophyllia, 451 



disarticulation. On some specimens there is still to be seen, at rare 

 intervals, a single spine attached by its solid base to the stem, 

 while on numerous other examples, where the booklets have not been 

 fractured quite close to the stems, their bases are seen projecting a 

 short distance from the costae. In one specimen the booklet has been 

 broken off near the stem, but the matrix retains a cast of the de- 

 tached spine ; the contour of which, from base to apex, is perfectly 

 even and unbroken, an appearance incompatible with the alleged 

 mode of attachment. The above facts clearly show that there was 

 no articulation of their bases upon rounded tubercles, which would, 

 it appears to me, be quite an anomaly in the structure of a zoophyte. 



A specimen of what seems to have been a fragment of this coral 

 was figured by David Ure in his Natural History of Rutherglen and 

 East Kilbride, in the year 1793, pi. xix., fig. 11. Ure does not de- 

 scribe the specimen further than by stating that it was beautiful on 

 account of its denticulation, and that it was rare. He placed it 

 among his Coralloides. 



Prof. McCoy's Serpula hexicarinaia evidently belongs to this coral, 

 or to a closely allied species of Heterophyllia. His specimen seems to 

 have shown no internal structure, nor any of the external spinous 

 processes : this led him to conclude that it was some anomalous 

 species of Serpula. The absence of structure and external markings, 

 may have been due to the specimen having been preserved in a 

 crystalline limestone. M'Coy thus defines the organism in his Car- 

 boniferous fossils of Ireland. " Serpula hexicarinaia, pi. xxiii., fig. 

 28, sp. ch. Elongate, slightly flexuous, hexagonal ; sides nearly 

 equal, smooth, flat ; rounded, prominent keel on each of the angles. 

 This species is easily distinguished from any other of the Palseozoic 

 Serpula, by the hexagonal form of the tube, and the six, narrow, 

 rounded keels on the angles. Length usually about two inches, 

 width half a line." 



So closely does the above description answer to small, worn 

 specimens of H. miraUlis, that my specimens were long identified 

 with M'Coy's fossil, and as such appeared with his name in my lists 

 with a (?), as I was satisfied that it could not belong to the genus 

 Serpula, but was a zoophyte closely allied to other forms I had 

 found at Brockley near Lesmahagow, which Dr. Duncan has now 

 placed, no doubt correctly, among Professor M'Coy's Heterophyllia} 



Craigenglen, Campsie, has yielded the finest preserved specimens 

 of the coral under discussion, and as these specimens seem to prove 

 the identity of the two so-called species, one of the specific names 

 adopted by Dr. Duncan must be allowed to drop. I would, there- 

 fore, suggest that that of H. mirahilis be the one retained, as it is 

 given to the specimen which represents the most perfect condition 

 of the coral. 



1 In the Catalogue of tlie collection of fossils in the Museum of Practical Geology, 

 page 129, Serpula hexagona is mentioned from the Glasgow district. Unfortunately 

 as the authorities for the species are not given in that work, I am unable to state 

 whether that species be the same as M 'Coy's 8. hexiearinata. But I suspect that it 

 is, and if so, then it must be referred to the genus of corals in question, for I know 

 of no hexagonal form of Serpula fi-om the Carboniferous strata of Scotland, especially 

 from the Glasgow district, with the fossils of which I am well acquainted. 



