J. W. HULKE ON THE STERNAL APPARATUS IN IGUANODON. 473 



34. Note on the Sternal Apparatus in Iguanodon. 

 By J. W. Hulke, Esq., P.R.S., F.G.S. (Eead June 10, 1885.) 



[Plate XIV.] 



One of the few parts in the osteology of Iguanodon upon which the 

 rich series of Bernissart fossils preserved in the Musee d'Histoire 

 ^N'aturelle at Brussels, so ably worked out by M. Dollo, and con- 

 cerning which the numerous remains discovered in our own country 

 have hitherto not afforded any certain information, is the sternal 

 apparatus*. 



A specimen which I lately had the pleasure of seeing in the rich 

 collection of /(/wfmocZon-remains made from the Wealden Beds at 

 Hastings by S. H- Beckles, Esq., F.R.S., a EeUow of this Society, 

 appeared to me to supply the desired knowledge. Mr. Beckles 

 readily acceded to my wish to bring it under the Society's notice ; 

 and I tender him my warm thanks for his permission, and also for 

 most courteously placing this and other fossils at my disposal for 

 examination and study. 



The piece which I identify as part of the sternal apparatus is an 

 azygos bar, from near one end of which two lesser rods diverge 

 laterally, one from each side (PL XIY. fig. 1). Each of these rods 

 (cZ) has an expanded mesial end, a contracted cylindroid shaft, and a 

 swollen outer extremity. The expanded mesial ends are applied 

 to that surface of the azygos bar which I regard as ventral, 

 approaching each other here so closely as to leave between them 

 only a very narrow interval in which the bar is visible. Their 

 dimensions are as foUows, viz. : — 



Length 22-5 cm. 



Breadth of mesial end 16-5 „ 



„ shaft at its middle 5*0 „ 



Longer diameter of outer end 7*5 ,, 



Extreme distance between outer ends 46-5 „ 



The identification of these divergent rods with the bone cemented 

 by rock to an Iguanodon scapula in the British Museum (recognized 

 first as clavicle by Mr. W. Davies), and also with the two bones 

 figured by M. Dollo as the right and left moieties of the sternum 

 (PL XIY. fig. 2), will not, I think, be questioned. Some minor 



* Other parts of the pectoral arch — the scapula and coracoid — have long been 

 known, the clavicle more recently. The latter was first, I think, recognized as 

 such by Mr. W. Davies. His identification was accepted by Prof. O. C. Marsh, 

 and subsequently by myself, with some reservation (Quart. Journ. G-eol. See. 

 vol. xxxix. p. 6i). 



