194 SCHEDIASMA 



" Genus II. — The Echinoconus ii an Echinus, whose ajiertures are lofh in the base, the 

 oral in the centre, and the anal at or in the mar(ji7i. 



It is either of a conical figure (the Echinites pileatus of Luidius), or hemispherical, or 

 more or less compressed or oval. All of them have five duplicate pointed Unes 

 extending from the vertex to the oral aperture. 



I have observed various fossil species of this genus, but only one recent species. 



I have given it the name of Echinoconus from the conical figure which certain 

 species possess. 



Table II, fig. 1. — The Echinoconus vere conicus ; perfectly conical, fossil; filled 

 with cretaceous matter. From the Kent chalk pits. The Echinites pileatus, with either 

 a conoid figure, or somewhat turbinated. [Plates XLIX and L of this work.] 



Pig. 2. The base of the same, in which may be observed the oral aperture in the 

 centre and the anal in the margin. [Plate L, fig. 1. Echinoconus conicus, Brey.] 



Fig. 3. The Echinoconites hemisph^ricus ferme, nearly hemispherical, consisting 

 of siliceous matter, or of what is commonly called hornstoue. [Plate LIII, fig. 2 c, (/.] 



Fig. 4. The base. [Plate LIII, fig. 2 b. Echinoconus subrotundus.'] 



Fig. 5. Echinoconus ovalis, the anal aperture near the margin. This is the only 

 recent one known to me ; it does not exceed half an inch in size, is fragile, and with a 

 whitish shell. 



Fig. 6. The base. 



Genus III. — The Echinocorys is an Echinus with both ajjertures in the base, the oral 

 between the centre and the margin, and the anal as distant as possible from the 

 moicth in the margin itself. 



All those which have come under my observation approximate in some measure in 

 their form to that of a helmet. Hence they are termed by Luidius in his 'Litho- 

 phylacium Britanuicum ' galeati or helmeted. 



I have designated the genus Echinocorys for the same reason, as Kopuc among the 

 Greeks signified a helmet or casque. Hitherto I have observed no recent specimen of 

 this genus, but many fossil ones. 



Table III, fig. 1. The Echinocorys vulgaris ; fossil, filled with cretaceous matter, 

 from the chalk pits near Gravesend, Kent. This is the common helmeted Echinites 

 of Luidius. 



Fig. 2. The base of the same, with two apertures; the upper one is the mouth, the 

 lower the anus." 



