EXPLANATION OF PLATE 27. 43 



Fig. 8. a. Tube on the under surface of a scale for the 

 passage of the mucous duct. See V. I. Note, p. 

 150. (Agassiz.) 

 Fig. 9. Anterior extremity of the lower jaw of Holop- 

 tychus Hibberti, from the Limestone of Burdie 

 house, near Edinburgh. See Note, V. I. p. 209. 

 The rugged surface of this bone is very remarkable. 

 (Hibbert.) 

 Fig. 9'. Small teeth of Holoptychus Hibberti, fluted ex- 

 ternally towards their base, and having a hollow 

 cone within. (Hibbert.) 

 Fig. 9". A small tooth magnified. (Hibbert.) 

 Fig. 10. One of the larger teeth in the Jaw of Holop- 

 tychus Hibberti, deeply fluted at the base, and having 

 a hollow cone within. None of these teeth have 

 sockets, but they adhere by a bony attachment to 

 the jaw. (Hibbert.) 

 Fig. 11. Tooth of Holoptychus Hibberti. (Hibbert.) 

 Fig. 12. Tooth of Megalichthys Hibberti.* (Hibbert.) 

 Figs. 13, 14. Teeth of Holoptychus Hibberti. (Hib- 

 bert.) 

 Figs. 11. 12. 13. 14. are from Burdie house. 



* Since the discovery of Megalichthys, which we have quoted in 

 V. I. p. 210, Mr. W. Anstice, of Madeley, has found two jaws and 

 punctate scales of the same species, in nodules of Iron stone from the 

 Coal field of Coalbrook Dale; he has also found Ichthyodorulites, bones 

 of fishes, and Coprolites, forming the nuclei of other balls of the same 

 Iron stone. 



Mr. Murchison has still more recently (1835) discovered remains of 

 the Megalichthys, Holoptychus, and Coprolites, with several species of 

 Unio, in the Wolverhampton Coal field. These great Sauroid fishes, 

 which were first recognised at Edinburgh, in Sept. 1834, have also 

 been detected in the English Coal fields of Newcastle on Tyne, Leeds, 

 and Newcastle under Lyne. 



