664 MR. G. A. BOULENGER ON PTERYGOID [DcC. 2, 



2. On the Presence of Pterygoid Teeth in a Tailless Batra- 

 chiau {Pelobates cultripes) , ^ith Remarks on the Locali- 

 zation of Teeth on the Palate iu Batrachians and Reptiles. 

 By G. A. BouLEXGER. 



[Received November 1, 1890.] 



On recently examinino; some disarticulated bones of Batrachians, 

 which I prepared in 1877, and which I had not looked at since, I 

 was very much surprised to find a few small teeth on the left ptery- 

 goid bone (the right one had been lost) and on the parasphenoid in 

 a skull of Pelobates cultripes. My attention once drawn to this 

 point, which is of considerable importance from the fact that ptery- 

 goid teeth haye not yet been recorded in any living Batrachian, I 

 examined the various skulls of Pelobates in the British Museum, 

 and also removed the mucous membrane from the palate of several 

 specimens in spirit, with the result that, although I have failed to 

 detect any teeth on the pterygoids or parasphenoid of Pelobates 

 fuscus, I have succeeded in finding pterygoid teeth in two other 

 specimens of P. cultripes, one from Nantes, the other from the 

 south of France. I will designate the former specimen as a, the 

 latter as b, and the imperfect skull (from Bordeaux), mentioned 

 above, as c. 



In all three these teeth are small, grain-like, resembling the same 

 in various Stegocephala ; the mucous membrane of the palate has to 

 be removed to ascertain their presence ; they are evidently in a rudi- 

 mentary condition. 



In specimen a there are about ten teeth on the parasphenoid, at 

 the base of the longitudinal branch of the ^-shaped bone, and two 

 pterygoid teeth close together on the left side. Specimen b has no 

 teeth on the parasphenoid nor on the left pterygoid, but shows a 

 group of eight distinct teeth on the right pterygoid. In speci- 

 men c, as iu a, there are about ten teeth on the parasphenoid, and a 

 series of four on the left pterygoid (the right being lost). 



Our knowledge of the localization of the teeth on the various bones 

 of the palate in Batrachians and Reptiles has so much increased of 

 late ^ that it appears to me usetul, on this occasion, to review and 

 tabulate the data available at present in recent and fossil forms. 



AVhUst in not a few fishes all the bones of the palate are toothed, 

 it is only among the lowly Stegocephala that we meet, higher up in 

 the scale, with such a disposition. As evolution proceeds in both 

 the Batrachian and Reptihan phylse, we find the palatal dentition 

 more and more localized and reduced. Thus, in the Urodeles or 

 tailed Batrachians, we have frequent examples of a toothed para- 

 sphenoid, no form, however, showing teeth on the pterygoids, but all 

 agreeing iu having them on the vomers and palatines -. In the 



1 A table, verv iucoiuplete even at the time it was published, of the dentition 

 of recent Batrachians is given by O. Hertwig in his admirable memoir " Ueber 

 das Zahnsystem der Amphibien," Arch. mikr. Anat. xi. Suppl. (1874). 



- In the Protcidcs the ])alatines are not 3 et separated from the pterygoids 

 ia most Urodeles they are fused with the vomers. 



