I1IE LOWER GREENSAND OF NEW ZEALAND. 331 



DESCKIPTION OF PLATE XXI. 



• ISCHYODUS BREVIROSTRIS, Ag. FigS. 1-5. 



Fig. 1. A right mandible, from the Cambridge phosphatic deposits, seen from 

 the inner side : a, laminated tooth at extremity of beak ; b, syniphysial 

 tooth of tubular dentine ; c, anterior and outer tooth of tubular den- 

 tine ; d, posterior and outer tooth of tubular dentine ; e, median tooth 

 of tubular dentine ; os, oral surface ; s//, symphysial surface ; x, pos- 

 terior angle. In the Museum of Practical Geology. 



Fig. 2. A portion of the beak of a left mandible from Cambridge, having the 

 outer surface ground away to show the laminated structure of the 

 tooth. In the Museum of Practical Geology. 



Fig. 3. A portion of the surface of one of the tubular teeth, enlarged six dia- 

 meters, showing the central tubes and the surrounding dentine. In 

 the Museum of Practical Geology. 



Fig. 4. A right mandible from the Gault of Folkestone. The original type of 

 the species alluded to in Agassiz's 'Poissons Fossiles,' iii. p. 344. In 

 the collection of the Earl of Enniskillen. Letters as in fig. 1. 



Fig. 5. A right mandible from the Lower Greensand of New Zealand. In the 

 British Museum. Letters as in fig. 1. 



Calloriiynchus Hectori, sp. nov. Figs. 6-9. 



Fig. 6. A right maxilla from the Lower Greensand of New Zealand, showing the 

 lower or oral surface : a, the inner spur of the tooth ; b, the outer 

 spur of the tooth. In the British Museum. 



Fig. 7. Same specimen, enlarged. 



Fig. 8. Same specimen, enlarged, front view. 



Fig. 9. ,, ,, outer side. 



Discussion. 



Mr. Etheridge stated that he had been called upon to examine 

 carefully the large series of fossils brought from New Zealand by Dr. 

 Hector, and that he had been much struck with those associated 

 with the specimen of Ischyodus noticed by Mr. Newton. These 

 were undoubtedly of Cretaceous type ; and the deposit, in its general 

 conditions, appeared closely to resemble the remarkable beds of 

 Upware and Farringdon. Mr. Newton's paper was of great import- 

 ance, as throwing much light upon the distribution in time and 

 space of so interesting and remarkable a group as the Chiinaeroid 

 fishes. 



Sir Philip Egerton was gratified to find that the divisions esta- 

 blished by him in this group of fishes some twenty years ago still 

 held good. Mr. Newton's determination of the Ischyodus was cer- 

 tainly of great interest, as demonstrating the occurrence in New 

 Zealand of a species belonging to our own Greensand. 



The Author stated that the nearest ally of his new form appeared 

 to be the living Calloriiynchus. The maxilla was remarkably well 

 preserved ; and its single tooth seemed to furnish evidence of the 

 existence of three teeth in the lower jaw. 



Q. J. G. S. No. 127. 



