PLA'J^E XVII {continued). 



'»• 



4 a. AcRosALENiA LowEANA, Wright, p. 240. Upper surface of the test, natural size. 

 /;. Lateral view of the test, natural size. 



c. Two inter-ambulacral plates, a portion of the ambulacral area, and poriferous zones, 

 magnified three diameters. 



5. AcROSALENiA WiLTGNii, Wright, p. 246. The apical disc, magnified three times. 



Spines of unhioivn Species. 



(). Globular spine from the Great Oolite near Bath, magnified three times. 



7. Spine from the Forest Marble of Upper Cubberly, near Cheltenham, natural size, 



and magnified three times. 

 8 Spine from the Great Oolite of Bath. 



a. Spine ditto ditto, 



y. Spine from the Stonesfield slate of Eyeford, Gloucestershire, and surface magnified 



five times. 



10. Spine from the Stonesfield slate of Eyeford, Gloucestershire, and surface magnified 



four times. 



11. Spine from the Great Oolite of Minchinhampton, natural size. 



12. Spine from the Pea-grit, near Cheltenham, fragment natural size. 



13. Spine from the Lower Lias of Bushley, near Tewkesbury, and a portion magnified 



five times. 



14. Spine from the Lower Lias of Lyme Regis, and portion magnified four times. 



15. Spine ditto ditto, and portion magnified five times. 



16. Spine ditto ditto, and portion magnified three times. 



