a 
THE MARSIPOBRANCHII. 131 
tionships with the less numerous and less specialized ones 
of Chimera and (through that genus) with those of certain 
Hlasmobranchs, they admit of a comparision with the 
supports of the accessory buccal folds of the Myxinoids ; 
and if, as I herein seek to show, (fra) they may be 
regarded as homologous with the main cartilages of the 
Lamprey’s sucking lp, the resemblance between that 
structure and the well pronounced fold (/. ac.) of the 
antarctic Chimeeroid becomes most striking. 
I have elsewhere* emphasized the conclusion that the 
structure of the reproductive organs of the Amphibia and 
Holocephali and of the Marsipobranchii are referable to 
two totally distinct types; the facts upon which this 
areument is based, considered conjointly with those above 
alluded to, render it, to my mind, inconceivable that there 
can be any near relationship between Amphibians and 
Marsipobranchs, and, therefore, that the sucking-mouthed 
stage of the former (which is confined to certain Batrachian 
forms) can be anything but secondarily acquired. Callor- 
hynchus, viewed from the same standpoint, would appear 
to furnish evidence, not only that the question ‘‘ whether 
a sucking mouth be primitive or not”’ is to be decided in 
the negative,t but of an independent evolution in the 
Holocephah (Callorhynchus) and Marsipobranchii (Myx- 
inide) of closely similar types thereof. 
The chondrocranium of certain lower Urodela (ex. 
Proteus, Menobranchus), with its absence of so-called 
‘occipital arch,” with its nonfusion of the anterior ends 
of the trabecule and its widely open floor which accom- 
panies this, with its independence of the pre-ocular (ant- 
* loc. cit., p. 556. 
+ Beard, loc. cit., p. 746. 
