46 PROF. G. B. HOWES AND MR. H. H. SWINNERTON ON THE 
quadrate. And in this connection it may be remarked that if the detailed configura- 
tion of the cartilaginous upper jaw be a criterion of relationship, the fact that a near 
approach to the condition occurring in Sphenodon is that of the Cecilian Ichthyophis 
glutinosa as recently described by Winslow ! is of great interest, when it is remembered 
that these Apodal Batrachia, in the possession of dermal ossifications and other well- 
known characters, are the most approximately Stegocephalian of all living forms ?. 
The Hyoid and Columella auris.—Our observations concerning the hyoid apart from 
its connection with the auditory apparatus are few. At the earliest stage we have 
examined (viz. P) it has already appeared in procartilage in the form it assumes in the 
adult, except for slight differences in general proportion, as is better seen at Stage Q 
(Pl. III. fig. 4). We have no evidence pointing to a compound origin of its basal 
portion such as that described by Gaupp ? for the Amphibian, or of the complexity in 
structure of the order described by Siebenrock 4 for the Chelonia. 
It is only as concerning the vexed question of the relationship between the colu- 
mella auris and the anterior cornu of the hyoid that we need proceed to details. The 
nature of this in the adult has been so oft recapitulated that it will suffice to point 
out once more that, apart from theories based on alternative interpretations of the 
facts of adult anatomy and surmises necessary for their defence, the real question 
developmentally at issue is whether or not the hyoid cornu and the extrastapedial are 
secondarily united, and whether the object called by Huxley suprastapedial does or 
does not arise independently. 
Huxley, in describing the parts of the adult, regarded® the whole columellar 
complex as hyoidean, and the extra- and suprastapedial processes as parts of its 
expanded outer extremity. Peters, and all subsequent investigators °, on the contrary, 
with the exception of Versluys, who has recently argued? in favour of original con 
tinuity, have assumed that the connection between the extrastapedial and the hyoid 
cornu is secondary, while Peters more especially believed the suprastapedial to have 
been originally distinct. As great testimony to the extreme care with which Huxley 
worked at this problem, there stands the fact that he drew attention (op. cit. p. 398) to 
the presence, on the inner side of the foramen (f-h., text-fig. 11, which for brevity’s 
sake we associate with his name), of a fibrous differentiation included between the 
extra- and suprastapedial processes. 
* Winslow, G. M.: Tuft’s Coll. Stud. vol. i. no. 5, 1898, pl. ili. fig. 24. 
* Cf. Boulenger, G. A.: P. Z. 8, 1895, p. 402. 
* Gaupp ,E.; Morph. Arbeiten, Jena, Bd. iii. 1894, p. 399. 
* Siebenrock, F.: Ann. naturhist. Hofmus. Wien, Bd. xiii. 1898, p. 424. 
* Huxley, T. H.: P.Z.S8. 1869, p. 391. 
* Peters, W.: Monatsber. Akad. Wiss. Berlin, 1870, p. 15, and ibid. 1874, p. 40. Cf. also Baur, G.: Biol. 
Centralbl. Bd. vi. 1887, p. 655; Killian, G.: Jen. Zeitschr. Bd. xxiv. 1890, p. 649; Osawa, G.: 98°, p. 520. 
7 Versluys, Jan.: Zool. Jahrb, Anat. Abth. Bd. xii. 1899, p. 167. 
