1893.] Clavicular Arch in Tchthyosauria and Sauropterygia. 155 



Home's first figure is spoken of as showing " unnatural proportions 

 of the several bones." It is a generalised figure in which the scapulae 

 and the clavicles which rest upon them are about one-third too long, 

 and the interclavicle is about twice as wide in the staff as any speci- 

 men which I remember (though, perhaps, not wider than in a speci- 

 men figured by Cuvier), but in substantial accuracy of arrangement 

 of the bones the figure is admirable, and would be marvellous if made, 

 as Mr. Hulke implies, from dissociated bones. Mr. Hulke does not 

 point out any inaccuracy in the figure, which he reproduces, and no 

 evidence is referred to which is opposed to the position of the scapula 

 indicated in PL 2, fig. 1, 'Phil. Trans.,' 1818. 



In the same way the criticism upon Cuvier seems to me without 

 justification. It is stated by Mr. Hulke that, since " Cuvier copies 

 both the figure given by Sir E. Home and the figure given by Dean 

 Conybeare, and abstains from expressing his own views on the subject 

 (of the difference between them), obviously little weight attaches to 

 his authority in regard to it." 



In the first place, Conybeare and Home agree in representing an 

 anterior surface of the scapula in advance of the articulation of that 

 bone with the coracoid. Secondly, Cuvier, in the plate in which 

 Home's figure is copied, gives several admirable engravings of the 

 shoulder girdle from specimens, and his fig. 1 and fig. 5 demonstrate 

 that the scapula did extend a cartilaginous surface in advance of the 

 articulation with the coracoid. A cast of the specimen represented 

 in fig. 5 is preserved in the Natural History Museum. Cuvier's 

 figures show variations in size of the anterior notch between the 

 coracoid and scapula. 



FIG. 4. Shoulder girdle of Ichthyosaurus, after Cuvier, i natural size (' Oss. Foss.,' 

 PL 258, fig. 1). 7. C., interclavicle ; CL, clavicle ; cor., coracoid; Sc.^. 

 scapula ; /, coracoid foramen ; V, vertebrae ; r, ribs. 



