68 
of the trunk”. Between the mesial bones of these two transverse 
series, there is a median rhomboidal plate, also considered by Tra- 
QUAIR as a proper scale of the trunk, but said by Macacı to be the 
homologue of the “préinterpariétal unique rhombique de VYhomme”. 
This latter bone in man is said by Maaai to arise by the fusion of 
four separate and distinct preinterparietal centres of ossification, which 
may, however, not fuse to form a single bone, but be found, in the 
adult man, fused with each other or with the neighbouring bones in 
various combinations. The single median bone of Polypterus can 
accordingly be assumed, according to Maaai, to be formed by the 
fusion of four ‘‘petites plaques osseuses correspondant aux préinter- 
paritaux de l’homme”. Between it and the four interparietals, behind, 
and the so-called parietals of the fish, in front, there are four bony 
plates in transverse line which Maccı calls the retroparietals or post- 
parietals, and of which he says, “c’est une série qui doit étre mor- 
phologiquement unie aux plaques parietales”. These four bony plates 
are the four mesial supratemporal bones of TRAQUATR’s descriptions, 
and they are said by Maaear to be represented in man by two centres 
of ossification found by him in the posterior part of each parietal; 
the anterior part of each parietal of man being represented, in Poly- 
pterus, by the so-called parietal bone of the fish. As the parietal of 
WIEDERSHEIM’S figure of Polypterus, to which alone Maaat refers, is 
the squamoso-parietal of VAN WIJHE, we thus have the parietal of man 
formed by the fusion of the true parietal, the dermo-squamosal, and 
two of the three supratemporal elements on each side of the skull of 
Polypterus. Still another bone, “l’os de l’obelion”, may also be fused 
with these several elements. The third supratemporal element of 
Polypterus, which, in WIEDERSHEIM’S figure, lies between the lateral 
halves of the lateral plates of the two transverse series, I can not 
definitely trace in the discussion. It may, however, be the fourth centre 
of ossification of the parietal, said by Macar to be sometimes found 
in man, and to be found in Rhinosaurus as an anterior epiotic bone. 
The homologue of the squamous part of the temporal bone of higher 
animals is found by him, in Polypterus, in the operculum, and in the 
Stegocephali in the so-called supratemporal bone of those animals. 
The “lamelles triangulaires ou lamelles latérales de Pozzi’, in man 
and certain other mammals, are said to be represented in Polypterus 
in scales that lie posterior to the interparietals of his descriptions; 
that is in the second row of scales posterior to the supratemporal 
bones. 
