268 



THE GEOLOGIST. 



Fig. 14. Produdus longisjpinus. From the original specimen of Sowerby's P. 

 Flemingii ; West Lothian and collection of Dr. Flemingi 



15. . Interior of the ventral valve ; from Capel E.ig 



and collection of Mr. Armstrong. 



16. , Dorsal valve, from the same locality. 



17. -. From the Campsie main limestone ; collection 



of Mr. Young. 



18. . A curious variety from Gare. 



19. . A variety in which the sinus has not been 



developed ; Prod, spinosus, Sow., from the original example, slightly 

 restored, and collection of Dr. Fleming. 



20. aculeatus, Martin. From the Campsie main limestone. 



21. mesolohus, Phillips. From the Glarat lime-works, Campsie ; 



collection of Mr. Young. The shell has also been recently found at 

 Brockley, near Lesmahago, by Mr. J, Thomson. 



22. costatus, Sow. From Barrhead ; collection of Mr. Young. 



23. , Sow. From near Lesmahago; collection of Dr. Slimon. 



24. , Sow. Dorsal valve, Barrhead. The interior of the 



dorsal valve has been recently found at Brockley, by Mr. Thomson. 



25. ?• Undetermined species. From Corrie Burn ; collection of 



Mr. Young. 



26. • Youngianus, Dav., type. The usual condition of the species, 



from the same locality and collection ; in pi. v., fig. 7 shows the con- 

 centric lines of growth. 



27. fimhriatus, Sow. From Lanarkshire, 



Plate W- liL 



1. Proditctus semireticulatus, Martin. From Castlecary ; collection of Mr. 



Thomson. 



2. ■ . Nellfield, Lanarkshire. 



3. . Interior of the ventral valve. From Calder- 



side ; collection of Mr. Armstrong. 



4. . Interior of the dorsal valve. From Calder- 



side ; collection of Mr. Armstrong. A, occlusor ; B, divaricators ; 

 J, cardinal process. Fig. 4a, cardinal process seen from its upper 

 sm'face. Fig. 4b, a smaller portion of the internal sm-face close to 

 the margin, showing the spinose asperities, M, which covers its sui'- 

 face, as well as the orifices of the minute canals which traverse the 

 shell, N. 



5. , P. Scotica, Sow. From the original specimen 



in the collection of Dr. Fleming. Figs. 7 and 8 show the disposition 

 of some of the ribs. 



n. , var. sulcatuSy Sow. From Carluke parish. 



10. , var. Martini. From ii'onstone under the 



Campsie main limestone ; collection of Mr. Somerville. Fig. lOh 

 shows how the ribs bifurcate upon the latei'al portions of the valves. 



1 1 . . From the same locality. 



12. , var. P. concinnus. From the same locality ; 



and sho-^^^ng how the shell becomes sometimes fractured. 



13. cora, d'Orbigny. From the Campsie main limestone (Bal- 



grochan Clen beds). A more correctly enlarged fragment of the 

 shell sm-fat-c wiU be seen in pi. v., fig. 5, 



14. carhoiHiriu.s, de Koninck. In the collection of the Geological 



Survey this spechnen is labelled " North of GlasgoV (?), a very 

 vague indication ; and it is possible that the specimen may be from 

 some other district of the Scottish Carbonilerous series. 



1^- undaius, Defrance. From the Campsie main limestone. 



