PLATE XI J. 



Fk;. 1.— a. 8phaerotyU(i< anfmrticm Kirkp. Nat. size : p. 10. B. Polymastia invaginata Kirkp. ; p. 15. 

 (Note. The surface pile is, in tlie natural condition, more uprii^lit than in this specimen, where it 

 has been crushed down.) C. The larger of the two small specimens above is Sphaerotylus capitatus 

 Vosmaer, nat. size ; p. 18 ; the smaller is S. antarcHcus. 



Figs. 2, a. — Sp/iaerolylm antarc/kus, young specimens. Nat. size. 



Fig. 4. — Portion of another young specimen ( x 25). 



Fig. 5. — Sphmrotyluit antarrticu'i. A spheroidal specimen. Nat. size. 



Fig. (;.— Style from radiating main fibre (x lot*)- 



Fig. 7. — Style from inner cortical tangential layer (x loO). 



Fig. .s. — Spherostyle ( X lOO) ; Sa head of same ( X 125). 



Figs. 9-12. — Heads of various spherostyles (x 425). 



Fig. 13.— Slender curved choauosomal tyle (x 100). 



Fig. 14. — Beaded tyle from radial fibres (x 425). 



Fig. 15. — Curved cortical tyles of outermost layer of cortex (x 100) ; 15a, the same (x 160). 



Fig. 10.- -Straight tangential tyle of lower cortical layer (x 100) ; 10a, the same (x 425). 



