398 Prof. W. K Parker. Amphibian and Reptilian [Feb. 23, 



need not now state anything further with regard to them, as 

 I have already given in my papers on the Skull of the Snake, 

 the Lizard, the Edentata, and Insectivorous Mammalia, numerous 

 figures and descriptions of them. I must, however, repeat one or 

 two facts ; in the Snake and Lizard these gland-like bodies lie each 

 in a little dish, formed by the vomer of that side, covered in by 

 another vomerine bone — the septomaxillary. They are also protected 

 at the opening of the capsule by a pedate tract of cartilage, derived 

 from the ali-nasal fold, which, in the Snake, frequently becomes 

 detached from its root. 



In low Mammalia there are several vomers, ten in Guscus maculatus, 

 a low kind of Phalanger. Now in most of the lower kinds of Mammalia, 

 examined by me, a pair of small anterior vomers lie on the inside of 

 Jacobson's organs, but the capsule itself is formed by a peculiar fold 

 of cartilage — the recurrent cartilage, which closes in upon itself and 

 unites its edges round the gland. 



As a rule these "recurrent cartilages " retain their union with the 

 alinasal folds, as in the Lizard ; in the Rabbit they are distinct, as in 

 the Serpent (Howes). 



Now in Birds these cartilages not unfrequently appear, but no 

 " Jacobson's organ " has been found with them. The Birds whose 

 vomerine region comes nearest to that of a low Mammal are the 

 " Turnicidae," or Hemipods, and the great group of the Passerine birds 

 (Coracomorphae, or .iEgithognathae of Huxley). 



It is not uncommon for the ox-faced vomer of these birds to be 

 formed of two pairs of bony centres, and these become not only fused 

 together, but actually grafted upon the floor of the cartilaginous 

 nasal capsule, in the same manner as is common in the lower kinds of 

 Mammalia. 



Now I find remnants of the cartilaginous capsule of Jacobson's 

 organs, not only in the Hemipods and in the lower Neotropical 

 Passerines (Homorus, Synallaxis, Anosretes), but also in some of the 

 highest of the singing-birds, namely, the Wren (Anorthura troglo- 

 dytes), and also in some of the Woodpeckers (Picidae), outside the 

 Passerine order. 



In my paper on the " Skull of the Ostrich Tribe " (' Phil. Trans.,' 

 1866, Plate 10, fig. 14, a.i.t.), I figured and described, but did not 

 understand, a peculiar cartilage perched right and left upon the 

 large vomer of the Rhea. I have been for a long time satisfied that 

 this also is one of the vomerine or Jacobson's cartilages, and this view 

 is corroborated, and to my mind proved, by what my son has found 

 in the palate of the Apteryx. 



Now if my son's figure* of the transversely- vertical section through 

 these cartilages and the crura of the vomer in the Apteryx, be com- 

 * In the Paper preceding this. 



