TAILLESS BATRACHIANS. 



35 



parasphenoid (psp), and the pterygoids (pt). On the back of the 

 skull are the exoccipitals {eo), with a condyle on either side of the 

 foramen magnum for articulation with the first vertebra ; there is 

 no basioccipital. The toothless lower jaw is composed of several 

 bones, as in the Reptiles, to which may be added on each side a 

 peculiar symphyseal [sy) . 



The number oi presacral vertebrce [v) is normally eight; the 

 ninth, or sacral [sv), gives attachment to the pelvis. The vertebrae 

 possess strong transverse processes but no ribs, and, save in the 

 first and last two, the centra are procoelous or concavo-convex. 

 The coccyx or urostyle [c) is a long styliform bone, usually 

 articulating with the sacral vertebra by a double concavity receiving 

 the double condyles of the latter. 



The pectoral arch (fig. 23) is composed of a pair oi precoracoids 

 ipco) and a pair of coracoids [co) nearly parallel, and firmly con- 

 nected in the median line by a narrow cartilage, the epicoracoid 

 [eco) ; this structure of the pectoral arch is termed the '' Fu-mi- 

 sternal,^^ to distinguish it from the " Arciferous '■* type as seen in 

 many families — for instance the Toads, in which the coracoid and 



Fig. 24. 



Sternal apparatus of Leptodactylus pentadactylus. 



])rec()raeoid on the one side are connected by an arched epicoracoid 

 cartilage overlapping that of the other side (fig. 24). In front is 

 the omosternmn {ost), composed of a cartilaginous disk and a bony 



