392 M. DoUo — Belgian Fossil Reptiles, 



EXPLANATION OF PLATE XI. 



(OSTEACODA FROM THE LONDON ClAY.^) 

 FiS. 



1. Bairdia suhtrigona, Bornemann. 



2. „ Londiniensis , sp. nov. 



3. ,, ovoidea, sp. nov. 



4. Cythere arenosa, Eosquet. 



5. ,, scabropapulosa. 



6. „ „ var. aculeata, nor. 



7. ,, scalaris, sp. nov. 



8. „ scrobiculoplicata, Jones. 



9. Cythereis Bowerbankiana, Jones. 



10. a, b. „ aranea, sp. nov. ; b, ventral aspect. 



11. a, b. ,, Prestwiehiana, sp. nov. ; b, transverse section. 



12. Cytheridea perforata (Eoem.), var. insignis, Jones. 



13. ,, glabra, Jones. 



14. a, b. Krithe Londiniensis, sp. nov. 



15. a, b. ,, glacialis, B. C. and R. 



16. Oytheropteron triangulare (Reuss). 



17. Cythereila fabacea, Bornemann. 



18. „ Beyrichi (Eeuss). 



19. „ compressa (Mxinster). 



{To be continued.) 



II. — On some Belgian Fossil Eeptiles. 



By Louis Dollo, C.E., 



Assistant Naturalist in the Eoyal Museum of Natural History of Belgium, 



Brussels. 



I HAVE read with much interest the two articles which Messrs. 

 G. A. Boulenger and E. Lydekker have recently published in 

 the Geological Magazine,'^ and I should be very much obliged 

 if you would permit me to make an addition, which appears to me 

 useful, and which I should be glad to see published. 



1. PsEUDOTKiONYX.^ — 1. I have remarked with satisfaction that 

 it has been possible for the above-named naturalists to refer to 

 P. Delheidi, a Tortoise of the London-clay. This discovery is doubly 

 interesting, in the first place because it shows the existence of the 

 Belgian fossil in England, in the second place, because it establishes 

 the existence of the Bruxellian (Middle Eocene) Chelonian in the 

 Ypresian epoch (Lower Eocene). 



2. I do not, however, believe that the absence of the horny scutes 

 in JPseudotrionyx would be sufficient to create a new family.* In 

 fact, I think, for reasons which I shall explain elsewhere,^ that 

 the Thecopliora^ without horny scutes (Gymnoderras) proceeded 

 from types which possessed them (Lepidoderms). I believe also that 



^ See also woodcuts in the text. 



^ E. Lydekker and G. A. Boulenger, ' On Chelonia from the Purheck, "Wealden 

 and London Clay,' Geol. Mag. June, 1887, p. 270. E. Lydekker, ' Notes on Hord- 

 well and other Crocodilians,' Geol. Mag. July, 1887, p. 307. 



" L. Dollo, ' Premiere Note sur les Chelouiens du Bruxellien (Eocene moyen) 

 dela Belgique,' Bull. Mus. Roy. Hist. Nat. Belg. 1886, t. iv. p. 75. 



* E. Lydekker and G. A. Boidenger, ' Chelonia,' etc. p. 274. 



^ L. Dollo, ' Premiere Note sur les Chelouiens oligocenes et neogenes de la 

 Belgique,' Bull. Mus. Eoy. Hist. Nat. Belg. 1887, t. v. (in the press). 



^ L. Dollo, 'Chelouiens du Bruxellien,' etc., p. 79. 



