318 Proceedings of the Royal Physveal Society. 
a specimen in not quite so good a state of preservation as 
some which it has been my good fortune to secure; the tail 
is copied from Smith Woodward’s figure in Natwral Science 
(4, fig. 1). I suppose he interprets as “external gills” the 
two narrow post-occipital plates (# in the present figures), on 
which he has drawn certain lines, as if to indicate a sort of 
tufted appearance, which I certainly have not observed in 
any of the numerous specimens which I have examined. 
Whatever may be the morphological signification of these 
plates, they cannot be external gills. It is also difficult to 
see where the “elongated nasal bones” come in, unless the 
author thereby means the two long external cirri, which are 
given in his figure in somewhat exaggerated proportions. 
As regards amphibian affinities, Sir J. W. Dawson’s sug- 
gestions give us a rather wide range of choice between 
highly specialised limbless Stegocephali and a “primitive 
Tadpole,” which one would expect to be a creature of a 
somewhat more generalised type. As regards the former 
alternative, I must confess that I fail to see any sort of 
resemblance to Palwospondylus, except the want of limbs, 
which is a feature common to many vertebrates of widely 
separated affinities; while as to the latter, the primordial 
cranium of a Tadpole bears just the same sort of resemblance, 
and no more, to that of our little Paleozoic vertebrate that it 
does to the skull of Petromyzon. But no amphibian, adult 
or embryo, with which I am acquainted shows a median 
cirrated opening, presumably a nose, in front of the head. 
On the other hand, in support of the Marsipobranch theory 
we have the following facts :— 
1. The skull is apparently formed of calcified cartilage, 
and devoid of discrete ossifications. 
2. There is a median opening or ring, surrounded with 
cirri, and presumably nasal, in the front of the head. 
3. There are neither jaws nor limbs. 
4. The rays which support the caudal. fin-expansion, 
apparently springing from the neural and hemal arches, are 
dichotomised (at least the neural ones), as are the correspond- 
ing rods in the Lamprey. 
But not only are no jaws to be found, but also no traces 
