OP A HIGHER FOKJVL OF LIFE ON A LOWER FOEM. 429 



water into them whilst struggling with a drowning prey, he thought 

 this exclusion was brought about mainly by the closure of the ex- 

 terior nostrils, since if these were closed, the nasal passage being 

 filled with air and not a vacuum, water could not enter the poste- 

 rior nares by the mouth. It was, however, the exclusion of water 

 from the glottis and not from the posterior nares which is important. 

 The narial passages and trachea do not form a continuous, but an 

 interrupted tube, without the admirable contrivance which Cetaceans 

 have of a conical larynx, which can be raised and plugged into the 

 palato-nares ; for the upper opening in Crocodiles is a simple slit, 

 not particularly prominent, and not capable of such exact adjustment 

 to the palato-nares as in Whales. 



Mr. Hicks asked if, with the cessation of the existing circum- 

 stances, the acquired structural modifications would cease and the 

 Crocodile go back to its primitive form. 



Sir Philip Grey-Egerton observed that in the beginning of the 

 paper the author noticed the modifications of structure of mammals 

 adax)ted to the surface of the earth, the splay-footed ones moving better 

 over the soft surface ; but it must not be overlooked that with these 

 coexisted narrow-footed forms. He thought that the author should 

 have shown that the splay-footed ones alone existed then. 



Prof. Owen, in reply to Dr. Meryon, said that he was gratified to find 

 that his paper had called forth the remarks to which he had listened 

 with pleasure from his old and esteemed friend. It would be seen, 

 however, that his paper was teleological rather than evolutionist, indi- 

 cative of how the structures characterizing the Neozoic Crocodilia would 

 operate in giving them advantage in the capture of terrestrial prey. 

 Wo doubt a reference had been made to the Lamarckian view of the 

 conditions under which such modifications of structure might be 

 acquired, and the requirements, by an objector, of the intermediate 

 stages of the change from the amphiccelian to proccelian types was 

 referred to. Instances of that character were few, but might be 

 cited. The Mesozoic GoniopJiolis, e. g., with broad thick jaws, wavy 

 alveolar tract, and large and unequal teeth, combined these Neozoic 

 characters with the Mesozoic large, horizontal, advanced palato-nares. 

 The existing Gavial retains the long narrow jaws, straight alveolar 

 tract, numerous small and similar-sized teeth, with the small, sub- 

 vertical, posteriorly placed palato-nares characteristic of Neozoic 

 Crocodiles. Considering the enormous lapse of time between the 

 Wealden and Eocene periods, it may reasonably be expected that 

 many more of these " missing links " will be found ; and one object 

 in our allusion to them in this paper, honoured by Dr. Meryon's 

 remarks, was the additional stimulus it held out to paleontologists 

 and intelligent collectors of fossils to researches which might be re- 

 warded by such discoveries. 



With regard to that part of Mr. Hulke's objection bearing on the 

 scutal characters of Mesozoic and Neozoic Crocodiles, it is true that, 

 as Natterer has pointed out, the ventral as well as the dorsal scutes 

 of the Jacquari are ossified ; but those scutes are less firmly con- 

 nected together; they are united neither by the peg-and-groove 



