294 PEOCEEDIKGS OP THE GEOLOGICAL SOCIETY. [Feb. 21, 



the disk, where they are not broader than one- third of their inter- 

 stices ; double anteriorly and posteriorly, where they are equal in 

 width to the interstices; hinge -line long, straight, forming an 

 abrupt angle with the rounded anterior margin ; posterior margin 

 with an oblique slope. 



59. Pecten exaspeeatus, Sow. 



Sow. Thesaurus Conch, vol. i. p. 54, pi. 18. f. 183-6; Eeeve, 

 C. I. Pecten, pi. 2. f. 7 & 8. 



This Pecten still lives in the West Indian seas. The fossil has 

 20 ribs, and is slightly longer than the recent shell ; but I cannot 

 regard the differences as specific. 



60. Pectei^ tn^-^qtialts. Sow. PI. XYIII. fig. 6. 



Quart. Journ. Geol. Soc. vol. vi. p. 52. 



61. Chama aecin-ella. Lam. 



The Jamaican shells do not differ from the recent examples ; but 

 the San Domingan specimens may be considered a variety. The 

 former have more numerous imbricating subtubular spines, which 

 in the latter are not so regularly arranged in rows, and assume 

 more the character of coarse squamose granules. 



EXPLANATION OF PLATES XYL-XYIII. 



(Illustrative of Tertiary Shells from Jamaica). 



Plate XVI. 



Fig. 1. Conus solidus, Sow. 



2. stenostoona, Sow. 



3. interstinctus, Gruppy. 



4. gracilissimus, G-uppy. 



5. granozonatus, Guppj. 



6. Meurotoma Jamaicense, Gruppy. 



7. Conus 'planiliratus, Sow. 



8. Columbella ambigua, Guppy. 



9. Cerithium pleheium, Sow. 



10. Colwnbella gradata, Guppy. 



11. Pkos Moorei, Guppy. 



12. Fasciolaria semistriata, Sow. 



13. Phos elegans, Guppy. 



Plate XVII. 



Fig. Natica jphasianelloides, d'Orb. 

 Marginella coniformis, Sow. 

 Vermettis ])apulosus, Guppy, 

 4. Dentalium dissimile, Guppy. 

 ba, 5 b. Cyclostrema bicarinatum, Guppy. 



6. Fleurotoma Barretti, Guppy. 



7. Cancellaria Moorei, Guppy. 



8. Cassis monilifera, Guppy. 



9. Malea camura, Guppy. 



10. Cassidaria suhlcBvigata, Guppy. 



11. Cancellaria Barretti, G(\x^^j . 



12. IcBvescens, Guppy. 



13. Persona simillima, Guppy. 



