Prof. J. van der Hoeven on the Genus Menobranchus. 363 
XLVI.—Notes on the Genus Menobranchus and its Natural 
Affinities. By J. van DER Horven*, 
One of the most important improvements in the natural distri- 
bution of Reptiles is undoubtedly the separation, effected by 
Merrem and F. S. Leuckart in 1820.and 1821, of that class into 
two groups, named by the former Pholidota and Batrachaa. 
(‘Tentamen systematis Amphibiorum, auctore Blasio Merrem, 
Marburgi, 1820.) The Batrachians have the skin naked, while 
the Pholidota have the body covered with scales or enveloped in 
two bucklers (Chelonia). Leuckart, by introducing the appel- 
lation Dipnoa for the Batrachians, has seized and made use of a 
more essential character, viz. the double respiration, the presence 
of branchiz at an early stage, or the existence of branchiz perma- 
nently with lungst. We owe to M. Fitzinger the name Monopnoa, 
corresponding to that proposed by Leuckart, and serving to dis- 
tinguish the other great division or that of the Pholidota of 
Merrem ft. 
The researches of various authors have contributed more and 
more to confirm this primary division. The celebrated physio- 
logist Miller has, above all, by drawing attention to certain 
anatomical characters which had not been sufficiently regarded, 
demonstrated the perfectly natural character of these groups§. 
There is, in fact, so great a difference between the reptiles of 
these two divisions that Merrem considered them two distinct 
classes—an opinion shared by De Blainville. It does not enter 
into our present purpose to discuss this view; we would, how- 
ever, remark that the doctrine advanced by a modern author, 
according to which the Dipnoa should be united with the Fishes, 
seems to us an exaggeration, and opposed to a truly natural 
classification. 
Among the reptiles with double respiration we must place 
* Translated from a separate impression, communicated by the author, 
from the ‘ Archives Néerlandaises, tome i. (1866), by Arthur O’Shaugh- 
nessy. 
+ Oken’s ‘ Isis,’ 1821, Litterarischer Anzeiger, 257-265 : “ Einiges tiber 
die fischartigen Amphibien.” 
+ Neue Classification der Reptilien, von L. J. Fitzinger : Wien, 1826. 
§ “Beytraige zur Anatomie und Naturgeschichte der Amphibien,” 
Zeitschrift fiir Physiologie, herausgegeben von F. Tiedemann, G. R. Tre- 
viranus, und L. C. Treviranus, iv. Bd., 2 (1832), p. 190 &e. This remark- 
able work dates at the commencement of the author’s scientific career ; he 
then occupied the chair of Physiology at the University of Bonn. Amongst 
the anatomical characters of the Dipnoa must be cancelled that of the 
simple auricle formerly attributed to the heart of Batrachians. (See the 
author’s supplementary note, pp. 274-275.) It is, however, especially 
worthy of remark, as a twofold embryological character, that both amnios 
and allantois are here wanting, while they are present in all other reptiles, 
as well as in birds and mammals. 
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