PLATE XV. 



(Carboniferous Species.) 



1. Cyrtina septosa, Phillips. From the original representation in the ' Geology of 



Yorkshire.' 



2. — — A fragment of ventral valve from Vise, Belgium, in the 



collection of Professor L. de Koninck, to show the inequality 

 in width of the ribs. 



3. — DORSATA, M'Coy. From the original figure in the 'Synopsis.' 



4. — — These figures are partly restored from a fragmentary specimen 



from Cork, Ireland, in the collection of Mr. Griffith. 



5. ? cARBONARius, M'Coy. From the figures in the work on 'British Palaeozoic 



Fossils.' 



6. — — A specimen from Kendal, in the Museum of Practical 



Geology. A portion of the shell of the dorsal valve 

 being removed, a single median sht is observable in 

 the cast, and not two, as would be the case in a true 

 Pentamerus. 



7. 10. — — Difierent specimens from Kendal. 



11, 12. — — Interior of the ventral valve; 12, section of the same. 



Kendal. 

 13, 14. — — Two sections, one horizontal the other transversal, pubhshed 



by Professor M'Coy, in his work on ' British Palaeozoic 

 Fossils.' 

 15 — 2G. Athyris ambigua. Sow. Fig. 15 from Bolland, British Museum; 16,17, 



in the collection of Professor Phillips ; 1 8 — 24, from 

 the Carboniferous shales of Carluke, Lanarkshire; 25 = 

 Ter. pentacdra, Phillips ; 26 = ^. trilobata, M'Coy, 

 from the figure ni the 'Synopsis.' 

 27,28. ? gregaria, M'Coy. Fig. 27, from the figure in the 'Synopsis.' 



Ireland; 28, another specimen in the cabinet of Mr. 

 Griffith. 



