Men'eics — Dollo's Dinosaun'a of Beniissart. 85 



Hulke in 1870, and failed to form any decisive o}3inion on its inter- 

 pretation, till I saw it again after Mr. Hulke's paper had been read. 

 Mr. Hulke regarded the fossil, which he described, as consisting of the 

 clavicle and interclavicle of Igitanodon. And, in a restoration, the 

 clavicles are shown divided from each other b}^ the interclavicle, which 

 has its chief extension posterior to them. The clavicles ai'e represented 

 as also articulating with the scapula ; while the coracoids, repre- 

 sented as passing behind the clavicles and anterior part of the 

 interclavicles, articulate for a shoi't distance with the sides of 

 the interclavicles, and afterwards with a hj^pothetical sternum, 

 which is supposed to pass behind the interclavicle. I regi'et to find 

 myself unable to adopt any one of these determinations. First, what 

 Mr. Hulke regards as sutures defining the specimen into clavicles 

 and interclavicles, I regard as fractures in the specimen. The 

 bones, which for the moment I will distinguish as the sternal 

 elements of Dollo, I regard as being in close median contact, as in 

 the Belgian specimen already cited. I am unable to admit that 

 these bones articulated with the scapula, because 1 have never seen 

 a facet on any Ljiianodon scapula, which could have received such a 

 bone. While the surfaces on Mr. Hulke's fossil sternum, which, 

 are supposed to have articulated laterally with the coracoids, seem 

 to me to have given attachment to sternal ribs. It is manifest from 

 evidence in the British Museum that the specimen found by Mr. 

 Beckles, and figured by Mr. Hulke, and represented in the British 

 Museum by an excellent cast, includes another ossification, extending 

 beyond the sternal bones of Dollo. Professor Cope has some 

 interesting observations on this subject in the American Naturalist 

 for February, 1886. First he suggests that the bones in dispute are 

 neither clavicles nor stei'num in the ordinary sense of the term, but 

 the pleurosteal elements in the sternum, which were developed so 

 that the long process extended backward and outward, as in the 

 sternum of a fowl. It happens that Diclonitis niirahilis lias these 

 elements perfectly preserved, and closely resembling in form and 

 arrangement the same bones in Iguanodon Mantelli. Professor 

 Cope, however, identifies his sternum with the sternum of Mono- 

 clonius crassus, so that he would place the coracoid bones in direct 

 articulation with these sternal bones, almost in the position in which 

 Dollo placed them originally. Professor Cope was imaware of the 

 true structure of the sternal apparatus, described by Mr. Hulke, or 

 he would not have pi"oposed to bring the coracoids into connection 

 with osseous surfaces, which in that fossil are manifestly separated 

 by a broad, thin, ossified mass, from any other bone. Nevertheless, 

 I entirely agree with Professor Cope that the bones in dispute are 

 not clavicles, and further, that the specimen to be understood must 

 be turned upside down, in the way which he suggests. I am also 

 prepared to accept these sternal elements as approaching more nearly 

 to the pleurosteal elements in the sternum of a bird than to any 

 other ossification, in so far as they are posterior to the articulations 

 for the sternal ribs ; but in position they are essentially the xiphoid 

 bones, which have preserved as marked and as distinctive an 



