SUPPLEMENT, PLATE VIL 



Spirals and loops developed by the Rev. N. Glass. 

 Fig. 

 1, 2, 3. Alrypa reticularis, Linne. Young shells from Wenlock shales, Shropshire. 

 4 to 6. „ 5, „ Young specimens of different sizes, developed by 



Mr. Glass to show the growth of the spirals and 

 enlarged. Wenlock shales, Shropshire. (P. 109.) 



7, 7 a, b. „ Barrandei, Dav. 7. Exterior, nat, size. 7 a, b. Literior enlarged, to 



show spiral attachments to the hinge-plate and loop. 

 Wenlock shales, Shropshire. (P. 114.) 



8, 8 « 3. „ marr/inalis, Dal. 8 a. Interior developed to show spirals with their 



spiny projections, attachments to hinge-plate, and loop, 

 enlarged. 8 b. Portion of one of the spiral lamellae, 

 much enlarged to show spiny projections. Wenlock 

 limestone, Benthall Edge. (P. 113.) 



9,10. Glassia elonyata,X)Si\. 9. Exterior, nat. size. ^a,b,c. Enlarged. 10. Nat. 



size. \0 a, b. Dorsal and ventral aspects of spires, 

 as developed by Rev. N. Glass and seen as a trans- 

 parency. Wenlock shales, Shropshire. (P. 119.) 



11 to 20. „ obovata, Sow., sp. 11, 12, 13, and 16. Nat. size. 11 a,b,c, d, 12 a, 



13 a, b, c, 14 and 15. Enlarged. Wenlock shales, 

 Shropshire. 17. Ventral aspect of the spirals and 

 attachments, nat. size. 18. The same enlarged, and as 

 it would appear entirely free from matrix. 19 a. 

 Dorsal aspect of the spirals and attachments, enlarged. 

 20. Spiral entirely removed from the shell. %Oa,b,c. 

 the same enlarged and shown in different aspects. 

 (P. 116.) 



