DEVELOPMENT OF THE SKELETON OF THE TUATARA. 55 



Bonlenger first showed him 1 to be probably in error. Baur, accepting Boulenger's 

 correction, has sought to show 2 that the bones regarded by him as the supra-temporal 

 and squamosal lie within the area of the " squamosal " of Sphenodon, and that that 

 bone is therefore compound. Shuffling the terms, he regarded the body of the latter 

 with its laterally visible processes as a " prosquamosal " ("squamosal" auct.) and its 

 posterior ascending process as the squamosal (" supra-temporal " auct.). 



Seeking for evidence in support of this in the Tuatara, Baur admits that none was 

 forthcoming in a skull of 25 mm. in length (pp. cit. p. 321). Not only have we failed 

 in all attempts to detect any such separation, but also to observe at any period traces 

 of a second element. While we fully admit that this so-called " squamosal " of 

 Sphenodon combines the structural relationships of the supra-temporal and squamosal 

 as originally defined, failing the discovery of any trace of its supposed double nature, 

 we are disposed, on consideration of the behaviour and all detailed relationships of the 

 supra-temporal in the Lacertilia, to regard it as a squamosal, and to interpret its 

 ascending limb, which meets the parotic process of the parietal, as secondarily acquired. 

 The alternative would be the introduction of a new term, in which neither 

 "squamosal" nor "temporal" were compounded, but we have no wish to render 

 confusion more confounded. The future can only settle the question, and we are 

 content to leave it to that. 



The Quadrato-jugaL This bone, as is well known, was first recognized in Sphenodon 

 by Dollo 3 , and later more fully described by Baur 4 . We have nothing to add to their 

 descriptive account of it. Its most characteristic feature is its enclosure with 

 the quadrate (qu. & q.j. 9 PI. IV. figs. 7 & 9) of a conspicuous foramen. Osawa, the 

 latest writer upon it, terms it (98 a . pp. 499 & 520) the "tympanic," presumably 

 on account of his inability to regard the mammalian tympanic as the homologue of the 

 quadrate ; and associated with the study of this bone there is a matter of no little 

 importance, if, as we believe, the tendency of our time is in error. 



Baur, in 1889, argued 5 against the generally accepted belief that the single 



Smith Woodward is not uniform in his terminology. Boulenger, on the other hand, is so, and, like ourselves, 

 he retains the terms for the hones to which they were originally applied i. e. for him, in both fishes and 

 reptiles, the inner is the supra-temporal, the outer the squamosal. Difficulty admittedly arises when but one 

 bone is present, and there is no doubt that in many such cases the problem can only be solved develop- 

 mentally ; but, on comparison of those lizards in which both bones are present, we believe him to be right in 

 regarding the bone which alone suspends the quadrate in the Ophidia (Brit. Mus. Cat. " Ophidia ") as the 

 supra-temporal, and not the squamosal as do Huxley and his followers. 



1 Boulenger, G. A. : Ann. & Mag. Nat. Hist. (ser. 6) vol. xi. 1893, p. 209. 



2 Baur, G. : Anat. Anz. Bd. x. 1895, p. 322, cf. also Amer. Nat. vol. xxx. 1896, p. 145. 



3 Dollo, L. : BuU. Mus. E. Nat. Hist. Belg. t. ii. 1883, p. 235. 

 1 Baur, G. : Zool. Anz. Bd. ix. 1886, p. 685. 



3 Baur, G. : Journ. of Morphol. vol. iii. 1889, p. 473. 



