1898.] ON THE SKELETON OF ALTTES OBSTETRICANS. 101 



Plate VIII. 

 Fig. 1. Left side view of the skull of a nestling FhaWwn flavirostris, showing 



the sutures, the absence of a nasal hinge, and the large size of the 



anterior narial aperture. In order to expose the whole e.\tent of the 



maxilla, the dentary border of the premaxilla has been removed. 

 Fig. 1 a. Ventral view of the same skull. The pterygoids, palatines, and 



vomer have been removed, in order to show clearly the schizognathous 



nature of the palate. 

 Fig. 2. Left side view of the skull of a very young nestling Sula _ leucogastra, 



showing the sutures and the large size of the anterior narial aperture. 

 Fig. 3. Left side view of a portion of the cranio- facial region of the skull of 



Phalac-rocorax carlo, to show the form of the masillo-paia'ine 



processes and nasal septum when seen from behind. The lachrymal 



has been removed. 

 Fig. 4. The same view of the skull of Fregata, ariel. 

 Fig. 5. The same view of the skull of Phaefhon. The maxillo-palatine 



processes are seen to have only a horizontal direction ; there is no 



nasal septum. 

 Fig. 6. The same view of the skull of Pelecanus ritfescens. Note the great 



vertical height of the maxillo-palatine processes, and the vestigial 



septum nasi. 



2. On the Skeletou of Regenerated Limbs of the Midwife- 

 Toad [Alytes obstetricans) . By W. G. Ridewood, D.Sc.j 

 F.L.S., F.Z.S. 



[Eeceived December 22, 1897-] 



The capacity which the larvae of the Anurous Batraehiaus 

 possess of regenerating lost limbs or parts of limbs was made 

 known to the world as long ago as 1769 by Spallanzani (12), and 

 was verified by Griinther ' in 1866 (11. p. 567) ; and although the 

 negative results obtained by Fraisse (6) in 1885 led this author to 

 doubt the possibility of such regeneration, the original observation 

 has recently received abundant confirmation at the hands of 

 Barfurth (2) and Boulenger (4. p. 98). But whereas, as is well 

 known, lost hmbs can be developed anew at any period of life 

 by certain Urodela, it is only in the larval stages of Anura that 

 such phenomena are to be observed. Barfurth concludes from 

 the results of his experiments that the capacity for reproducing 

 lost parts diminishes in Anuran tadpoles as the development 

 progresses, and on this hypothesis he explains the discrepancy 

 between the results of Spallanzani and Fraisse. 



With a view to following up the researches of Barfurth, Mr. 

 Gr. A. Boulenger, F.E.S., seized the opportunity, when in Belgium 

 in the spring of 1897, of procuring some fine full-grown tadpoles of 

 the Midwife-Toad (Ah/tes obstetricans) and of repeating Barfurth's 

 experiments upon them^. These tadpoles had been sp.awned in 



1 A mistake has evidently occurred in Owen's transcription of Dr. G-iinther's 

 manuscript. The statement " If a hind limb be cut off when the larva is about 

 two lines long it is reproduced " is meaningless, because the larva of that size 

 has no limbs. Tlie words " two lines long " were evidently intended to apply 

 to the size of the limb, not of the larva. 



- Barfurth employed tadpoles of the common frog [Ranafusca (temporaria)}. 



