PLATE LIX. 



(Figs. 1-12, 18-22, 26, 30, 31, 37, 38 by R. P. Whitfield; 13, 14, 24, 25, 28, 29, 32, 33 by E. Ehmons: 16-17, 23, 27, 34-SS 



by Q. B. Simpson.) 



Genus LIORHYNCHUS, Hall. 



Page 193. 

 LlORHYNCHUS LIMITAEIS, VailUXeill. 

 Figs. 1, 2. Dorsal and frontal views of a small individual. 



Marcellus shales (Gouiatite limestone). iScJioharie connty, N. Y. 

 Figs. 3-5. Frontal, cardinal and ventral views of a larger specimen. 

 Limestone of the Marcellus shales. Avon, N. Y. 



LlORHYNCHUS DUBIUS, Hall. 

 Figs. 6, 7. Ventral and dorsal views of a typical specimen. 

 Marcellus shales. Locality f 



LlORHYNCHUS MULTICOSTA, Hall. 

 Fig. 8. The exterior of a pedicle-valve of an elongate specimen, the regular gi-owth of which has been 



inteiTU])ted in the umbonal region. 

 Fig. 9. The brachial valve of a more orbicular and typical shell. 

 Pig. 10. A cardinal view ; showing the convexity of the tvalves. 

 Hamilton group. Western New York. 



LlORHYNCHUS MESACOSTALIS, Hall. 

 Fig. 11. The exterior of the pedicle-valve ; showing the inequal plication of the sinus. 

 Fig. 12. An internal cast of a large Virachial valve ; showing the position of the median septum, the elon- 

 gate muscular scars and the absence of plications on the lateral slopes. 

 Chemung group. Tompkins county, N. Y. 



LlORHYNCHUS Laura, BilHllgS. 

 Figs. 13, 14. Ventral and lioreal views of a rather elongate individual. 

 Fig. 15. Posterior view of the hinge-plate and crura ; showing the great elevation of the latter and their 



basal expansions. X 4. 

 Fig. 16. The same specimen, viewed from above ; showing the narrow, submarginal dental sockets, the 



broad triangular divisions of the hinge-plate, the median septum and the recurvature of the 



long crura. X 4. 

 Fig. 17. The interior of the umbonal portion of the pedicle-valve ; showing the open delthyrium, small 



teeth and faint muscular impression. 



Hamilton group. Widder, Ontario. 



LlORHYNCHUS Kelloggi, Hall. 

 Fig. 18. Cardinal view of an internal cast ; showing the cavities left by the dental plates, median septum 



and crura. 

 Figs. 19, 20. Dorsal and ventral views of a normal adult ; showing the obsolescence of plications except 

 upon fold and sinus. 



Hamilton group. Northern Ohio. 



LlORHYNCHUS QUADRICOSTATUS, VailUXeill. 

 Fig. 21. View of a crushed and somewhat distorted pedicle-valve of large size ; showing the character of 



the plication 

 Fig. 22. A small internal cast of the brachial valve in which the lateral plications are obsolete. 



