OPHIDIAN TASTE FOR BIRDS' EGGS. 67 



birds by devouring their eggs.' Its remarkable organization 

 is favourable for the passage of these thin-shelled eggs 

 unbroken until far back in the throat or gullet, when the 

 egg comes in contact with certain ' gular teeth,' which 

 then break the shell without any loss of the contents to 

 the feeder. These gular teeth are a curious modification of 

 some of the spinal processes, presenting a singular anomaly 

 in the presence of points of enamel on the extremity of some 

 of them. 



Professor Owen has very fully described this remarkable 

 development,^ and as his works have been the text-books 

 of many later physiologists, his words may here be quoted, 

 even at the risk of repetition. 



* In the rough tree snake, Deirodon scaber, with 256 verte- 

 brae, a hypapophysis — from l^xh (Latin, s?ib), an offshoot from 

 beneath — projects from the 32 anterior ones, which are 

 directed backwards in the first ten, and incline forwards in 

 the last ten, where they are unusually long, and tipped with 

 a layer of hard cement (dentine). These perforate the 

 dorsal parietes of the oesophagus, and serve as teeth. 



'Those who are acquainted with the habits and food of 

 this species have shown how admirably this apparent defect 

 — viz. the lack of teeth — is adapted to its well-being. Now, 

 if the teeth had existed of the ordinary form and proportions 

 in the maxillary and palatal regions, the Qgg must have 

 been broken as soon as it was seized, and much of the 

 nutritious contents would have escaped from the lipless 

 mouth ; but owing to the almost edentulous state of the 

 jaws, the egg glides along the expanded mouth unbroken, 



^ Odontography^ by Richard Owen, 1840, and Anatovty of the Vertebrates, 1866. 



