306 MR. W. K. PARKER ON THE OSTEOLOGY OF BAL/ENICEPS REX: 
by the lower plate of the vomer and by the palatines. ‘The latter bones are kept apart 
by the palatal plate of the vomer, but they have begun to form that tube-like prolonga- 
tion of the posterior nares which attains its fullness in the Crocodile. In the Green 
Turtle (Chelone mydas) the inferior vomerine plate reaches the pre-maxillaries anteriorly, 
thus keeping the maxillary palatal processes widely apart ; in this species the palatine 
plate of the palate bone is not so well developed as in the Logger-head. In the smaller 
Tortoises the descending portion of the vomer is less decidedly palatal, and we have 
now before us the skull of a small Emys which has articulated to the sides of its vomer 
a pair of ‘ turbinals,’ which are evidently the proper homologues of the ethmoidal palatal 
plates of Birds and of the turbinals of Lizards and Snakes. Professor Goodsir thinks 
that the palatine plate of the vomer of Tortoises and Turtles always consists essentially 
of these turbinal elements, which he names ‘ ethmoidal neurapophyses’ (op. cit. p. 145). 
The study of its development would prove or disprove this opinion. 
These small Chelonians with their feebly-developed and widely-separated ‘ palatines’ 
lead us to the Lacertians and Ophidians, creatures that expose their double vomer on 
the anterior palatine aspect of the skull, and have articulated to each moiety a very 
perfect osseous ‘ turbinal,’ which bone Professor Goodsir now (in these orders) considers 
to be a mere exogenous outgrowth or cortical ossification of the ethmoid (p. 155). We 
agree with him here, but not with his finding ‘ ethmoidal neurapophyses in the divided 
vomer,’ nor with his non-recognition of the actual homology of these Lacertian and 
Ophidian ‘ turbinals’ with those of the little Chelonian and of Birds generally. 
We now come to the structure of these parts in birds and mammals. The vomer of the 
Goatsucker (Caprimulgus europeus), slightly grooved above and carinate below, appears 
in the palate, between the inferior or palatine turbinals. In the Merlin (Falco @salon) 
these latter processes are anchylosed together, and form a large oblong mass behind the 
palatine plate of the pre-maxillary, and between the laminar origins of the palatine 
bones. The vomer, thin above and round below, articulates behind with the palatines, 
being wedged between their ascending plates ; in front it descends and forms a lozenge- 
shaped little block, notched in front and flat below, the inferior surface being quite 
palatal. This descending anterior part wedges itself in between and behind the palatine 
turbinals exactly as in the little Tortoise, supposing these bones not to have coalesced, 
which they seldom do, the Merlin itself being somewhat exceptional in this respect even 
among the Raptores. In the Rook, and in Corvine and Passerine birds generally, the broad 
emarginate anterior end of the vomer descends, and appears in front of and between the 
palatine turbinals. One more instance from the class of birds :—in the Albatros (Diomedea 
exulans) we have an exception to the rule mentioned by Mr. Goodsir (op. cit. p. 159), 
that the vomer is feeble when the palatines are large, and vice versd. In this large 
palmiped the vomer is two inches and a half long, the palatines being relatively large. 
Thin and laminar below, at its junction with the palatines, the vomer of the Albatros 
diverges above into two very considerable laminz, whilst it is smoothly carinate below. 
