PLATE XVI. 



Fig. 

 1 a. 



b. 



c. 



d. 



/■ 



2 a. 

 b. 

 c. 

 d. 



e. 

 /■ 



3 a. 

 b. 

 c. 

 d. 



4 a. 



b. 



5. 

 6. 



Acrosalenias from, the Inferior and Great Oolite. 



Acrosalenia Lycettii, Wright, p. 232. Upper surface of the test, natural size. 

 Under surface of the same, showing the wide decagonal peristome, natural size. 

 Lateral view of the same, showing both areas. 

 Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous 



zones, magnified three times. 

 Base of an ambulacral area, showing the trigeminal ranks of pores in this region, 



magnified three times. 

 A primary tubercle, with its prominent conical boss, highly magnified. 



Acrosalenia tustulata, Forbes, p. 242. Upper surface of the test, natural size. 

 Under surface of the same, showing the wide decagonal peristome, natural size. 

 Lateral view of the same, showing the small ambulacral tubercles, natural size. 

 Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous 



zones, magnified three times. 

 A primary spine, natural size, and the base of the same, magnified three diameters. 

 The body and spines in situ, on a slab of Great Oolite, natural size. 



Acrosalenia Wiltonii, Wright, p. 246. Upper surface of the test, natural size. 

 Under surface of the same, natural size, showing the narrow mouth opening. 

 Lateral view of the same, natural size, showing the wide miliary zone. 

 Two inter-ambulacral plates, a portion of an ambulacral area, and the poriferous 



zones, magnified three times. 

 A primary tubercle on its large prominent boss, magnified three times. 



Acrosalenia Loweana, Wright, p. 240. Test and spines in situ, natural size, on a 



slab of Forest Marble. 

 One of the primary spines, magnified five times, with transverse section of the same. 



Spine of Cidaris Yeovilensis, Wright. "I These new species will be described in 

 Cidaris Moorei, Wright. J the Appendix. 



