PLATE XII. 



Fig. 1. — Parallelodon reticulatus. The type specimen, figured by M'Coy, from the Lower 

 Limestone of Millicent. In the Griffith Collection in the Museum of Science and Art, Dublin. 

 (Page 142.) 



Fig. 2. — Parallelodon obtusus. A fine testiferous example from the Carboniferous Limestone of 

 Graigue, co. Limerick. Iu the Collection of the Geological Survey, Dublin. (Page 167.) 



Pig. 3. — Parallelodon obtusus. A reproduction of the drawing of the type specimen in Phillips's 

 * Geology of Yorkshire.' (Page 167.) 



Pig. 4. — Parallelodon obtusus. Portion of a left testiferous valve from the Carboniferous 

 Limestone of Thorpe Cloud, Derbyshire. My Collection. (Page 167.) 



Pig. 5. — Parallelodon obtusus. A right valve of large size. Same locality. My Collection. 

 (Page 167.) 



Fig. 6. — Parallelodon obtusus. Portion of a very large example, showing the sinuations of the 

 lines of growth in the neighbourhood of the byssal sinus. Same locality. My Collection. (Page 167.) 



Fig. 7. — Parallelodon ornatissimus. A young testiferous example. Same locality. My Collection. 

 (Page 155.) 



Fig. 8. — Parallelodon Fraiponti. Aright valve, from same locality. My Collection. (Page 165.) 



Fig. 9. — Parallelodon obtusus. The cast of a right valve, showing the posterior hinge-teeth. 

 Same locality. My Collection. (Page J 67.), 



Fig. 10. — Parallelodon Fraiponti. A right valve, from the Carboniferous Limestone of Settle. 

 In the Geological Collection of the York Museum. (Page 165.) 



Fig. 11. — Parallelodon decussatus. Castleton. (Page 159.) 



Fig. 12. — Parallelodon decussatus. A full-grown right valve, from the Upper Beds of the 

 Carboniferous Limestone, Trey Cliff, Castleton. My Collection. (Page 159.) 



Fig. 13. — Parallelodon Fraiponti. A right valve, from the Carboniferous Limestone of Castleton. 

 My Collection. (Page 165.) 



Fig. 14. — Parallelodon jallax. The left valve, showing the posterior hinge-teeth, from the 

 Carboniferous Limestone of Narrowdale. In the Collection of the Geological Survey, Jermyn Street. 

 (Page 161.) 



Fig. 15. — Parallelodon decussatus. A left valve, with the test nearly removed. Same locality. 

 Same Collection. (Page 159.) 



Fig. 16. — Parallelodon concinnus. The type specimen of M'Coy's Modiola concinna, from ihe 

 Arenaceous Limestone of Townparks, Killeshandra. Tn the Griffith Collection of the Science and 

 Art Museum, Dublin. (Page 153.) 



Fig. 17 .—Parallelodon concinnus. A left valve from the Upper Beds of the Carboniferous 

 Limestone of Trey Cliff, Castleton. My Collection. (Page 153.) 



Fig. 18. — Parallelodon concinnus. A left valve from the Carboniferous Limestone of Thorpe 

 Cloud. My Collection. (Page 153.) 



Pigs. 19 — 21. — Parallelodon concinnus. A series, showing stages of growth, from Trey Cliff, 

 Castleton. My Collection. (Page 153.) 



Fig. 22. — Parallelodon concinnus. The cast of the interior of the left valve, showing the adductor 

 scars, anterior and posterior hinge-teeth, and pallial line. From the Carboniferous Limestone of 

 Hill Bolton, Yorkshire. My Collection. (Page 153.) 



Fig. 22 a. — Parallelodon concinnus. An enlarged view of the hinge-teeth of the above specimen. 

 (Page 153.) 



