398 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
other nomenclature except that he used the term prosquamosal of 
Owen for the more external of the two elements. Ammon (’89) and 
Broili (:04) follow Baur’s paper (’86) without advancing any argu¬ 
ments for this course. My contribution to the discussion is the ad¬ 
vancement of new criteria for the determination of the squamosal 
bone. 
I am well aware that this transposition of terms is likely to lead to 
confusion but it must be remembered that the confusion was intro¬ 
duced by others and that I am only returning to the proper termin¬ 
ology, for, as I think I have shown, the more lateral element is the 
homologue of the mammalian squamosal and must receive that name, 
while the element intervening between the squamosal and the parietal 
should according to the law of priority be called the supratemporal 
for Bakker (’22) first applied that term to the bone adjoining the pari¬ 
etal in the teleost skull and in the same sense it was used by Owen 
(’53) for the inner element of the temporal region of the Ichthyosaurs. 
Owen’s (’65—’81) term prosquamosal which was adopted by Baur and 
other American students, is a synonym of squamosal and is conse¬ 
quently unnecessary. 
The quadratojugal demands a moment’s attention. In the Stego- 
cephala this extends from the articular end of the quadrate to a greater 
or less distance dorsally upon its external surface, articulating an¬ 
teriorly with the jugal (J.) and usually reaching also the maxillary 
( Mx .). Miall (’73, p. 236) states that in many Stegocephala'(Masto- 
donsaurus, Archegosaurus, Trematosaurus, etc.) the quadratojugal 
forms the outer part of the articular surface for the lower jaw. In 
certain forms (Sclerocephalus labyrinthicus , teste Credner, ’81-’89) this 
bone is separated from the quadrate by suture but in others according 
to Fraas (’89, pp. 54 and 72) quadrate and quadratojugal are indis- 
tinguishably fused. Broili (: 04) thinks that the same is true for 
Eryops. 
Another characteristic is that the quadratojugal is often overlapped 
from above by the squamosal, so that judging from the Stegocephala 
we may emphasize as its characters its close association with the articu¬ 
lar end of the quadrate and'its tendency to be covered by the squa¬ 
mosal. Is there any evidence of a bone with similar relations in the 
existing Amphibia? 
Riese (’92) found that in Tylotriton vermicosus a bony process of 
the quadrate connects with the maxillary which is greatly lengthened. 
