26 DR. p. H. CAllPENTEU ON CERTAIN POINTS 



(PI. I. figs. 10, 11), covers tlie point o£ convergence of the hydro- 

 phores. This covering, however, is closely similar to what is 

 universally recognized as the oral pyramid of Glyptosphcsra Leuch- 

 tenhergi (PJ. I. fig. 15), a point which the reviewer must surely 

 have forgotten, or he would scarcely have put forward the sug- 

 gestion contained in the paragraph quoted above. It is singular, 

 too, that he should not have been struck by the resemblance 

 between the grouping of the hydrospires round a central penta- 

 gonal space and the ambulacra diverging from the angles of the 

 low oral pyramid in Glyptosphcera (PI. I. fig. 15) or in SjohcBronis, 

 as shown in figures 18 and 20 on pi. xi. of Angelin's ' Icono- 

 graphia.' It is also somewhat remarkable that neither Barrande 

 nor his reviewer should have noticed the resemblance of the 

 " hydrophores " in Pyrocystis to the ambulacra of Proteocystis, 

 which are figured and rightly interpreted on the next plate of 

 Barrrande's monograph. A glance at this ought to have dispelled 

 all the reviewer's doubts as to the " hydrophores " belonging to 

 the oral pole. 



Barrande would also seem to have forgotten the closure of the 

 mouth by oral plates in Spliceronis, Glyjotosplicera, and Cyathocystis, 

 or he would scarcely have written of it as follows * : — " Cette 

 ouverture n'est accompagnee d'aucun appareil destine a la fermer. 

 Nous devons done concevoir qu'elle etait constamment ouverte." 

 On the following page he adopted Von Buch's opinion that the 

 large lateral opening is genital in function and the small one 

 near it anal ; and yet the ' Nature ' reviewer says that " the 

 accepted views are confirmed by Barrande." He also compared 

 the fourth and slit-like aperture close to ih.exaowth.oiAristocystis 

 (PL I. figs. 12, 13, d) to the peculiar folded structure described by 

 Volborth t in Glyptosplicera Leuclitenhergi (PI. I. fig. 15, d) ; and 

 the ' Nature ' reviewer adds : — " More closely still does it resemble 

 the ' reniform groove ' or ' semilunar pore ' figured by Forbes in 

 the fossils which he called Ajnocystis and ^cMnoencrimis." The 

 same idea had also occurred to myself, and I have been led to 

 conclude that there are a large number of Cystids in which an 

 opening like that of the water-pore of recent Echinoderms is 

 represented, and that it occupies a position close to the peristome 

 in or near the interradius CD. 



* Op. cit. p. 43. 



i" ' Ueber die riissischen Sphaeroniten,' p. 29, pi. x. fig. 1. 



