510 Mr, A. 8. Woodward on the 



LVI 1 1. — Oyi the Affinities of the Cretaceous Fish Protosphy raena. 

 By A. Smith Woodward, F.L.S., of the British Museum 

 (Natural History). 



In 1889* it was incidentally pointed out that a remarkable 

 resemblance could be observed between the jaws and dentition 

 of the Cretaceous fish Protosphyrcena and those of the Upper 

 Jurassic genus Ilypsocormus. Since that date further im- 

 portant information has been published in reference to the 

 osteology of the first-named genus t, while beautiful examples 

 of Ilypsocormus have been acquired by the British ^luseum 

 from the Lithographic Stone of Bavaria and the Oxford Clay 

 of Peterborough. The opportunity is therefore afforded for 

 extending comparisons further, and I undertake this task with 

 all the more interest since it is now proved beyond doubt that 

 Protosphyrcena differs from all known "Teleostei" (i.) in the 

 structure of the pectoral fins, (ii.) in the development of the 

 splenials in the mandible, (iii.) in the structure of the large 

 teeth, and (iv.) in the presence of a large gular plate, followed 

 by a numerous series of comparatively short and broad 

 branchiostegal rays. 



All the new evidence combines to show that the original 

 suggestion of five years ago was one of some importance, and 

 it now appears that Protosphyrana mxidi Ilypsocormus vesemhle 

 each other in at least the following seven prominent characters. 



(1) Eostrum and Upper Jaw. — The ethmoidal region is 

 consolidated into a pointed rostrum, usually more produced in 

 Protosiliyrcena than in Ilypsocormus, but similarly fused at 

 the base with the small vomers, which bear a pair of very 

 large teeth %. As shown by an example of //, tenuirostris in 

 the Leeds collection from the Oxford Clay of Peterborough 

 (Brit. Mus. no. P. 6917), the premaxilla is triangular in that 

 fish, and both this bone and the maxilla agree closely with 

 the corresponding elements of P. nitiJa, as described and 

 figured by Felix {loc. cit. pi. xiii. fig. 1). As in Proto- 



* Smith ^^'oodward, " Preliminary Notes on some new and little- 

 known l^ritish Jurassic Fishes,'" (ieol. Mag. [3] vol, vi. p, 4ol (ISSi^). 



+ J, Felix, " Beitrii^'e zur Kenntniss der (lattuug Protospht/rctna, 

 Leidy," Zeitschr, deutsch. geol. Gesell. vol, xlii. pp, iTS-^W:?, pis. xii,- 

 xiv. (18'JO) ; A. 11. Crook, '' Ueber einige t'ossile Knoolientischo aus der 

 mittleren Kreide von Kansas," Pahvontogr, vol, xxxix. pp. lO'J, HO 

 (1892). 



t From tin- Cambridge Greensjuul iW writer is acqTminted with 

 luidescribed evidence of a species of Protosphtfrcirnit with a snout as short 

 as in Ilypswormus tenuirostris. 



