148 PROF. G. B. HOWES ON jacobson's [Feb. 17, 



is therefore interesting as invalidating such an interpretation, as well 

 as the morphological significance attached by Albrecht to his 

 specimen, the bifid limb of which, 1 have no doubt, was likewise 

 produced by regeneration. Whether the case now noticed is one of 

 reversion, as 1 have noticed in the scaling of the reproduced tails 

 of Lizards, or merely comparable to the bifid or trifid tails of the 

 same Reptiles, is a point on which I will refrain from expressing an 

 opinion. 



Mr. Boulenger also exliibited young specimens and eggs of a 

 South-African Siluroid fish, GaJeichthys feliceps, which had been 

 sent to him by Mr. J. M. Leshe, of Port Elizabeth, with the infor- 

 mation that the ova had been obtained from the mouth of the 

 adult fish. The fact that in the genera Arius and Osteogeniosus the 

 male takes charge of the eggs in this manner was well known, but 

 Mr. Leslie's observation was of importance as adding a third, though 

 closely allied, genus to the list of the Siluroids which thus protect 

 their offspring. According to Mr. Leslie, the number of eggs in one 

 fish's mouth was about thirty, each of which measures about six lines 

 in diameter. 



The following papers were read : — 



1. On the Probable Existence of a Jacobson's Organ among 

 the Crocodilia ; with Observations upon the Skeleton of 

 that Organ in the Mammalia, and upon the Basi-Man- 

 dibular Elements in the Vertebrata. By G. B. Howes, 

 F.Z.S., F.L.S., Assistant Professor of Zoology, Royal 

 College of Science, London. 



[Eeceived February 17, 1891.] 



(Plate XIV.) 



I. The Black Caiman (Caiman iiiger), of Inter-Tropical America, 

 is, with the exception of Tomistoma, the only Emydosaurian living in 

 which the vomers are fr"eely intercalated between the bones of the 

 palato-maxillary series. In Tomistoma they are so disposed as to 

 he visible from beneath over a short and constricted area between the 

 })osterior ends of the palatines, as was first shown by Miiller and 

 Schlegel '. In Caiman niger they are, unlike those of all other Croco- 

 <lilia, prolonged forwards into the premaxillo-maxillary region, and 

 their inflated free ends (wo.'", Plate XIV. fig. 7) occupy a wide inter- 



' Cf. Huxley, Journ. Linn. Soc. Lond., Zool. vol. iv. pp. 17, 19 (1860). For 

 synonymy see Boulenger's Brit. Mus. Cat. of ChelonianB, Ehynchocephalians, 

 and Crocodiles, 1889, p. 276. 



