Hydractinia, Parkeria, and Stromatopora. 45 



Influenced, liowever, by the presence of the " primordial 

 chamber-cone" figured by Dr. Carpenter in pi. 72, cl-c4, and 

 pi. 73, fig. 2, II, I was induced to observe, in the short " Note on 

 Parkeria,''^ added to my paper on the Polytremata (Ann. & 

 Mag.- Nat. Hist. 1876, vol. xvii. p. 208), that it could be 

 hardly doubted that Parkeria was a species of Foraminifera, 

 but that '■' one of the chief characters of the Foraminifera," 

 viz. the " foraminated arete of which the so-called ' nummu- 

 line tubulation ' is an example," had not been demonstrated. 

 The chief object, however, of this " Note " was to state that 

 the fibre of which Parkeria was composed was not " arena- 

 ceous," and that the structure of Parkeria was not identical 

 with the " labyrinthic structure " of the foraminiferal test 

 Lituola nautiloidea, Lam., var. canariensis, D'Orb. 



Up to this time I was under the impression that Parkeria 

 had been a species of Foraminifera ; for I had only one speci- 

 men myself, in which I could see all that had been described 

 by Dr. Carpenter excepting the " primordial chamber-cone." 

 Subsequently, however, I began to doubt the Foraminiferal 

 nature of Parkeria ; and, the nucleus of my specimen in shape 

 presenting exteriorly the pointed end of a Belemnite, which 

 extended from one side of the sphere to the other, I began to 

 think that it had been a sponge which had grown round the 

 end of a Belemnite. But what sponge ? was the next ques- 

 tion. Luffaria seemed to be the only genus that in fibro- 

 reticulated horny structure, when fossilized, would come near 

 to that of Parkeria ; and so for some time I, from the 

 presence of this great foreign nucleus, abandoned the Forami- 

 niferal for the Spongial view, still not heartily, till June 

 last, when, my friend Mr. W. J. Sollas having given me 

 some more specimens of Parkeria obtained from the Upper 

 Greensand of Cambridge, amongst which was an entirely 

 wwinfiltrated central portion about ~\ inch in diameter that, on 

 fracturing the circumferential or hard infiltrated part when 

 the specimen was entire, had fallen like a nut out of its 

 shell, I abandoned both these views, as will be seen hereafter. 

 This nuclear portion also had been so broken as to expose the 

 centre, on one side of which is a small circular or ellipsoidal 

 cavity that appears to have originally contained the object 

 on which the organism had commenced its growth (PI. VIII. 

 fig. 13, c). 



Seeing, then, that Parkeria grew upon a foreign body which 

 was on one side of the centre, I also felt satisfied that no 

 Foraminiferous test, either recent or fossil, with which I was 

 acquainted, presented either the fibro-reticulated structure of 

 Parkeria or possessed a foreign body for a point d^appui to 



