604 
MR. W. K. PARKER ON THE STRUCTURE AND 
The meaning of these facts will come out with great distinctness when I come to 
describe their development in the “ Aglossal ” Toads ; and in all the Batrachia we have 
most instructive foreshadowings of the complex nasal labyrinth of the bird, and of the 
endless galleries of the ethmoidal and septal structures of carnivorous and herbivorous 
mammals. 
At once it may be well to state that in those higher forms the distal ends of the 
trabeculae, “ hypotrabecular ” or “recurrent cartilages,” do not straighten out as in 
these Batrachia ; but the hooked or retral condition seen in the Bird and Pig also occurs 
in many of the Batrachia. The median or keystone part (prenasal or basitrabecular 
cartilage) is but little developed in the Frog (Plate 54. figs. 1 & 2, pn.) ; it is more 
distinct i nPipa (Plate 62. figs. 5 & 6, pn.). 
The actual end of the trabecular cornu remains as a shrunken pedate process with its 
“ toe ” turned to that of its fellow of the opposite side ; this is the “ rhinal process ” 
of Huxley, whose figure (op. cit. fig. 9, p. 755) seems to show it as a distinct cartilage: 
it is, however, continuous with the outspread subnasal plate (al.n.) formed by expan- 
sion of the larval trabecular bar. 
In the same figure the foliar outgrowths of the trabeculae are called “ prsenasal 
processes” ( pn.l .); they correspond to the distal part of the trabeculae, and are very 
simple in birds and mammals (“ Pig’s Skull,” plate xxxvi. fig. 1, c.tr.). Moreover, as the 
comparison of these parts in many types teaches me, the outer cervicorn part answers to 
the floor of the down-turned alinasal growths of the hot-blooded Yertebrata. 
There is no appearance in the Frog of three distinct territories in the roof of the inter- 
nasal plate such as we see in higher types, namely aliethmoidal, aliseptal, and ali- 
nasal laminae, the plates whose outgrowths are the turbinals of those various regions. 
The trabecular floor (fig. 2) is the widest in front ; the ethmoidal roof is widest behind 
(fig. 1). In the very front of the nasal sac the cartilage becomes laminated, a sort of 
attempt at the formation of turbinals (“ Frog’s Skull,” plate x. fig. 3). Professor Huxley 
stated his doubts to me as to the existence of these laminae ; but new sections show 
the truth of my old drawings*'. 
The 2nd upper labial (u.l.") is a solid club, with an out-turned and pointed handle; 
the 1st (u.l. 1 ) is a pisiform cartilage, serving as a cushion on which the premaxillary 
rests. The annular ethmoid (“Frog’s Skull,” plate viii. fig. 7, eth.) is rightly represented 
in my 9th stage as beginning above as a transverse ectosteal bar ; but the chondrocranium 
afterwards calcifies, and then becomes completely ossified; the fore-and-aft extension 
of this “ os en ceinture ” varies greatly in different types of Amphibia, as this paper 
will show ; in Lissotriton punctatus the little skull becomes a very strong osteocranium. 
Professor Huxley calls the fore part of the cartilaginous palatine bar the “ antorbital 
process ; ” there is a pre-, post-, and superpalatine region here, the latter being the 
conjugational bar between the trabecula and the pterygo-palatine arcade, one of the 
* In the same plate the sections show the distinctness of the “ 2nd upper labial,” which acts the part of an 
ala nasi (see figs. 3 & 6, v.e.n.). I did not at that time see the meaning of my own sections and drawings. 
