1895.] Zoology. 857 
The student who desires to become acquainted with the opinions of 
authors on the points involved, cannot do better than consult Dr. 
Baur’s paper. His references to the literature are full, and his method 
in this respect is a model worthy of imitation. 
Having seen that Dr. Baur now agrees with me that the bone which 
supports the quadrate in the Ophidia is not the supratemporal (pro- 
squamosal) I will take up his older, but above last-mentioned paper on 
the Pythonomorpha. Like Owen, Marsh and Dollo, he does not per- 
ceive that this group is essentially distinct from the Lacertilia, and 
concludes with them that I have erred in alleging it to present affini- 
ties to the Ophidia. He places it in the order Lacertilia and in close 
proximity to the Varanide as did Cuvier. 
In order to determine this matter, it is necessary to know, in the 
first place, what the characters are that distinguish snakes from lizards. 
The superficial characters given by systematic writers generally as dis- 
tinguishing the Lacertilia and Ophidia, are quite insufficient for that 
purpose. Johannes Miiller’ first placed the distinction on a sound 
basis by showing that in the Ophidia the frontal and parietal bones 
descend to the basicranial axis as in no other vertebrates, thus closing 
the brain case in front, while in the Lacertilia this does not occur, 
and as the ali- and orbitosphenoid bones are rudimental or wanting, 
the brain case is without osseous wallin front, Some lizards present a 
distinct approximation to the Ophidian type in the strong decurvature 
of the parietal bones at the sides: these are the Annulati and the Anni- 
elloidea. These groups display a similar approximation in the continu- 
ous sutural union of the occipital and parietal elements, a condition 
universal in Ophidia, and rare in Lacertilia. 
I have pointed out’ another distinction between the two divisions, 
viz., that the supratemporal (* squamosal,” ‘ prosquamosal ”) is pres- 
ent in the Lacertilia and absent in the Ophidia. As it is, however, 
absent in the Annielloidea and Amphisbenia, I have not included 
it in the definition of the former suborder. This definition has not 
been adopted by those authors who erroneously regard the suspensor- 
ium of the quadrate bone in the Ophidia as identical with the supra- 
temporal of the lizards, but my view has now received the assent of 
various anatomists, as e. g., Prof. Baur. 
A third distinction is that the quadrate bone is supported by the 
paroccipital in the snakes, and the exoccipital in the lizards. Baur 
! In Tiedmann u Treviranus Zeitschrift f, Phisiologie, IV, 233 
? Proceeds. Amer. Assoc. Ady. Sci., 1871, p. 221; Trans. Amer. Philos. Soc., 
xiv, 1869, p. 29. 
