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THE MARSIPOBRANCHII. 129 
Sturiones, structurally and paleeontologically carry the 
former back to some early ancestral type of extreme struc- 
tural simplification, such as may well have possessed a 
still stronger Marsipobranch affinity.* 
VY. Since the appearance of Huxley’s epoch-making 
monograph on the cranio-facial apparatus of the Lamprey, 
it has been universally recognized that the resemblance 
between this and that of the Anuran Tadpole are of a 
very close order. Balfour, as is well known, laid much 
stresst upon the development of a sucking-mouth in 
these and other gnathostomata, believing (loc. cit. p. 264) 
‘that in the ancestral chordata the mouth had a more or 
less definitely suctorial character.’’ The late Dr. W. K. 
Parker’s monographs on the development of the skull 
teem with passages either implying or openly proclaiming 
belief in a Petromyzontoid ancestry for the Batrachia, such 
as is to-day largely accepted and taught.{ Dohrn, criti- 
cizing Balfour’s observations, has pointed out§ that the 
suctorial apparatus is not in all cases composed of homo- 
logous parts. The Parkerian conception that the Anura 
are ‘“‘ Marsipobranchs in their larval state’’ may be there- 
fore reconsidered. Not the least formidable objections to 
this, at the outset, are the totally different characters 
and constitution of the ‘“‘horny teeth” of the Anuran 
*The inability of paleontologists to detect the remotest traces of paired 
fins in the Ostracodermi must not be overlooked here, cf. A. Smith Woodward, 
Brit. Mus. Cat. Fossil Fishes, Vol. I, p. xvii Introd., and pp. 159 and 176, 
tComp. Emb. Vol. II, pp. 263—264. 
tef. Phil. Trans., 1881, Part I, pp. 3, 24, and 30; 1883, Part II, p. 376 
especially, and also pp. 417 and 451. It is worthy of remark that Huxley’s 
dictum reads (Jour. Anat. and Phys., Vol. x, p. 427) ‘‘the cranio-facial 
apparatus of the Lamprey can be reduced to the same type as that of the 
higher vertebrata, by means of the intermediate terms afforded by the Tadpole’s 
skull.” 
§ Naples Mittheil. Bd. v, pp. 104—105 ; cf., also Beard op, cit, p. 745. 
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