125 



phoiiotret-x Scotlca var. Caiiadea^is now propose.l, in:iy peihaps nob be 

 entirely deemed inappropriate. Tiie spines in the Canadian specimens 

 examined so far are exceedingly minute and numerous, narrowly 

 cylindrical, pointed and smooth for the most part, ajid somewhat broad 

 and thickened at the base. Even under a high power of a microsoope 

 the spines a])iiear to be smooth, no anuulations being visible, whilst 

 irregularly distributed punctures at times appear to be present these 

 aie perhaps due to the mode of fossilizition. The number of spines 

 round the outer margin of specimen No. 2, {supra) has been roughly 

 estimated at over three hundred, forming only one of the many rows of 

 *' adpressed spines " ranging from the beak to beak round tlie anterior 

 front of the shell. 



It may not be deemed out of jjluce in this connection to give a 

 a list of the species of fossils associated with aS'. Scotica, Dav., and col- 

 lected at Craighead, in Ayrshiie, Scotland, chiefly by Mrs. R. Gray, a 

 lady wliose researches in and contributions to palsentology are well 

 known. They are all referred to the Llandeilo formation, a series of 

 measures undei-lying the Caradoc-Bala group, all members of the 

 Cambro-Siluiian or Ordovican System. The lust of Brachiopoda lias 

 been compiled from S.Davidson's "Supplement" (loc. cit.) and the 

 Crustacea are taken from the admii-able " Monograph of the Silurian 

 fossils of the Girvan district," by Dr. IT. A. Nicholson and Mr. Robt. 

 Etheridge,jr., F.G.S. 



The following is the list of species frou) Craighead in the Llandeilo 

 formation from which Slphoaotrela Scotica was obtained, those common 

 to Canada all italicised. 



BRACHIOPODA. 



1. Lin'jula quadrate, f'.ichwaltl. 12. Ortki Icstuilimiria, Dalmau. 



2. " Kanisayi, Salt<'r. 13. " confinis, Salter. 



3. Discinia peiTUgata, McCoy. 14. " biforata. Schlotheiu. 



4. Acrotreta Nicholsoni, Dav. 15. " turgida, McCoy. 



5. Leptmna sericea, Sow. 16. Strophomcna rhomboidalis, Wilckens. 



6. " temiicincta, McCoy. 17. " Imbrex, Pander, var. 



7. " Yoiuigiaiia, Dav. 18. " c.\i>aiisa, Sower'oy. 



8. " Grayiif, Dav. 10. ' retroilexa, Salter. 



9. Lept.Tiia Etheri'lgei, Dav. 20. lihyiiclioiiclla Balcletcliicusis, Dav. 



10. (?) Ortliis unguis, Sow. 21. " Peachii, Dav. 



11. Urtliis Sowerbyiann, Dav. 22. " Scotica, Dav. 



