FOSSIL VA RA NID AE AND MEGALANÏDAE. 
439 
are very highly specialized throughout for marine predaceous life and 
constitute a distinct subdivision of tho order Lacertilia.» It is for this reason 
that I exclude all affinity between the Mosasaurs and the Varanidae, consi¬ 
dering the former’s agreement or rather resemblance to the Dolicho- 
sauromorpha as based on the same convergence on which is 
founded the distant similarity on account of which Cope 1 , under the name 
of Pythonomorpha, regards Mosasauria as the ancient type of Ophidia. 
Such convergences are met with to-day also, for instance between Certain 
Lizards, — as with numerous Anguidae and some Scincidae for example, — 
and the Snakes. This leads us to another question of Varanidae- relationship, 
namely its connexion with the Ophidian order. Cope (op. cit.) first alluded 
to the «resemblances» between the skeleton of Mosasauria and Ophidia, 
considering the former, to which he gives the name of Pythonomorpha, as 
predecessors of Snakes. This theory, after more or less modification, 
has been acc;p!ed by numerous scientists. Likewise recently the «ober¬ 
flächliche Ähnlichkeit» 2 3 of the Adriosaurus- skull to Python was pointed 
out by Nopcsa, who regards Mosasaurs and Ophidians as 
parallel branches, the first having sprang from Aigialosauridae, 
the latter from Dolichosauridae. The resemblance between Mosasaurs 
and Snakes is truly very superficial, and I am unable to 
find an agreement in any important markings between the two groups 
mentioned, each of which representing, as I surely presume, highly specialized 
forms in comparatively very distant phyletical connexion with 
eachother, and thus cannot possibly be regarded as express¬ 
ing an orthogenetical parentage. I consider the Ophidia 
as a relatively ancient throughout highly specialized type, their 
origin doubtless leading back at least to lower Cretaceous 
Ophiomorph ancestors. Their genealogical relations to Lacertilia 
are therefore very far removed and their offshoot a 
most ancient o n.e. On the other hand a supposition of an 
Ophidian-Dolichosaurid connexion, as suggested by baron Nopcsa, should 
be excluded for the same reasons for which, with Osborn and Fürbringer, 
I must reject the possibility of an orthogene tic connexion between 
Mousasaurians and Aigialosauridae. The impossibility of such 
a relationship between Ophidia and Mosasauria or Dolicho- and, Aigialo¬ 
sauridae , was also ingenuously refuted by Dr. Janensch. 3 Mosasau* 
1 Fide Fürbinger, op. cit. p. 615. 
2 Z. Kenntnis d. foss. Eid. etc. p. 61. 
3 Üb. Archæoph. proav. Mass. e. Schlange a. d. Eocæri. d. Monte Bolca, Beitr. 
z. Palseont. u. Geol. Öst.-Ung., Bd. 19, Wien u. Leipzig, 1906, p. 26 — 31 & 32. 
