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GENUS XII. Ananchytes. Irregularly helmet-formed, 

 ovate or conoidal ; the ambulacra radiating from the vertex 

 to the margin, and even to the mouth ; the mouth labiated 

 and subtransverse, near the margin, at one end ; the vent at 

 the opposite end. PI. ii. upper surface, fig. 9, under sur- 

 face, fig. 12. 



The species of this genus are only known fossil. 



Synon. Cassis, galea, and galeola, Klein. Echino- 

 corytes, Leske. 



Sp. 1. An. ovata. Obovato-conoidal ; the vent ovate. 

 Leske ap. Klein, Tab. liii. fig. 3. Fossil, near Paris. 



2. A. striata. Ovato-rotund, raised, and much striated ; 

 the back convex, somewhat compressed, with numerous ver- 

 tical striae ; the assulae obsolete. Leske ap. Klein, Tab. xlii. 

 fig. 4. Fossil, Picardy. 



3. A. gibba. Ovate, raised ; the back ventricose, but, 

 at the top, compressed; the sides depressed inferiorly, with 

 light ambulacral interstices ; the vertex duplicate. Leske 

 ap. Klein, Tab. xv. fig. A. B. Fossil, from Normandy. 



4. A. pustulosa. Ovato-conical, pointed towards the 

 top ; depressed, and showing the assulae at the sides ; the 

 biporous lines of the ambulacra disposed in pairs ; the ver- 

 tex double and impressed. Leske ap. Klein, Tab. xvi. 

 fig. A. B. Fossil. 



5. A. bicordata. Obovate ; slightly grooved at each 

 extremity ; the back smooth, with a double vertex. 



Spatangites bicordatus, Leske ap. Klein, Tab. xlvii. fig. 6. 

 Fossil, from Mons. 



6. A. carlnata. Cordated, slightly grooved forwards ; 

 the back carinated in the middle. 



Spatangites carinatus. Leske ap. Klein, Tab. li. fig. 2, 3. 



7. A. elliptica. Ovato-elliptical and pulvinated ; with 

 two remote vertices ; assulae nearly obsolete. Knorr, Petr. 

 Tab. E. Hi. fig. 6. 



