1186 ON SOME ADDITIONAL LABYRINTHODONT FOSSILS, N. S. WALES 



The outer flanges of the lateral plates ("reflected process") appear 

 to be continued backwards beyond the points from which the 

 furrows radiate, and which may be called th sir centres of ossificati on. 

 These prolongations seem to be distinct bones, and may perhaps be 

 supraclavicles, as in the figure of the plates of Gondwanosaurns, 

 Lydekker, Pal. Ind. Ser. IV. I. 4. At each centre of ossification 

 is a pit, with a tubercular (?) centre, where I suppose the scapula 

 and coracoid to have approached, if not articulated with, the 

 thoracic plates or clavicules. The coracoid, however, is lost, like 

 the scapula, or was perhaps only cartilaginous and has left no 

 sign. At the outer angles of these laterals are some scattered 

 fragments which may possibly belong to the shoulder girdle. 



Their dimensions are as follows : — 



Medial Plate. 



Length 15 mm. 



Width (about) 13 



Length of each anterior margin 11 



Length of each lateral margin 9 



Length of the posterior margin 6 



Lateral (Left Side.) 

 Length from centre of radiation to anterior margin 



(about) 11 



Greatest width (about) 6 



[In Gondwanosaurus the thoracic plates appear to be identical, 

 though, of course, in a much more advanced stage of development, 

 with those of our specimen. " The central plate or interclavicle is 

 imperfect posteriorly, having been broken off posteriorly to the 

 central point from which the sculpture radiates ; this missing 

 portion has been restored in outline in the figure." But in our 

 specimen the plate, though perfect, is truncate and emarginate 

 posteriorly, and the same may have been the case with the Bijori 

 fossil. " When complete this plate formed an unsymmetrical 

 rhomboid, covered with a sculpture consisting of elongated pits 

 radiating towards the periphery from a centre situated at the 

 junction of the maximum longitudinal and transverse diameter. 



