54 PEOP. G. B. HOWES AND ME. H. H. SWINNEETON ON THE 



The " Squamosal" This bone has been most fully described by Baur, who J has 

 accurately dealt with its relationships to the parietal, postorbital, jugal, quadrato-jugal, 

 quadrate, and paroccipital process. It is unnecessary here to recapitulate the details 

 of this association, which our figures render sufficiently clear, except to remark that 

 we have extended the relationship to the pterygoid. 



In the progress of investigation into the comparative osteology of the fossil reptiles, 

 the varying conditions of the squamosal and supratemporal, one or both of which may 

 be present, have become the subject of much consideration. The presence of the two 

 has been regarded as a lowly characteristic, if only by way of analogy to the Stego- 

 cephalia. Cope and Baur are conspicuous among those who have utilized these bones 

 in the determination and discussion of affinity, and nothing short of a deplorable 

 confusion has arisen from their inconsistency in the usage of terms 2 , and the fact that 

 while one of them arrived at an inversion of the order adopted by certain contemporary 

 writers, he finally complicated matters 3 by needlessly reviving for the reptilian 

 squamosal Owen's term " prosquamosal." A final agreement was never arrived at, and 

 the question therefore arises as to which of the two bones is for the future to be 

 regarded as the supra-temporal. 



As a general rule these bones lie side by side in the same transverse plane. The 

 term supra-temporal was applied by Bakker to the inner one 4 , in dealing with the fish 

 skull. Cuvier denoted the presumably homologous bone in reptiles the "mastoid " 5 ; and 

 Owen, retaining this term, applied 6 to the outer of the two (Cuvier's "temporal") the 

 term squamosal. To be consistent, therefore, on the assumption that the inner of the 

 two bones, having similar relationships in fishes and reptiles, is homologous, 

 convenience and precision are met by terming the inner the supra-temporal, the outer 

 the squamosal. And it is in this sense that we use these words 7 . 



Our knowledge of the paleeontological history of the Rhynchocephalia has during 

 recent years been materially advanced by the description by Lortet of remains from 

 the Jurassic of France. In his memoir already cited (antea, p. 3) he drew attention 

 in Saphgeosaurus (Sauranodon) to a " parieto-squamosal " complex, in respect to which 



1 Baur, G. : Anat. Anz. Bd. x. 1895, p. 321. 



2 Cf. Baur, G. : Anat. Anz. Bd. i. 1886, p. 349, and Bd. ii. 1887, p. 657 ! and, as an awful example, the 

 series of notes embodying the dispute between him and Cope in Amer. Nat. vols. xxix. & xxx. 



3 Baur, G. : Anat. Anz. Bd. x. 1895, p. 320. 



4 In Cuvier and Valenciennes, Hist. Nat. des Poissons, t. i. 1828, p. 338. 

 6 Cuvier, P. ; Ossemens Possiles, t. x. 1836, p. 14. 



6 Owen, E. : Catal. Osteolog. Series E. Coll. Surgeons, vol. i. 1853 (table), p. xxxviii. 



7 Concerning the afore- mentioned confusion, Praas for example, in his revisionary memoirs on the Ichthyo- 

 sauria and Stegocephalia, following in respect to the latter the lead of Huxley, Miall, Fritsch, and Credner, 

 refers to the inner bone as the squamosal, the outer as the supra-temporal. Zittel adopts the Huxleyean 

 order for the Eeptilia and Stegocephalia, with confusion arising out of the interpretation of the latter in the 

 Lacertilia as the quadrato-jugal. Briihl is still more glaringly inconsistent and contradictory ; while even 



