138 The Ottawa Naturalist. [February 



The Hadrosauridae appear to fall into two natural groups or 

 subfamilies, the crested forms with a "footed" ischium, and the non- 

 crested ones having an ischium ending distally in a point. For these 

 subfamilies the names Saurolophinae and Trachodontinae respec- 

 tively were proposed by Brown in 1914. Saurolophinae, typified by 

 Saurolophus Brown, fully meets all requirements as a group-name. 

 Trachodontinae on account of the dubiousness of the genus Tracho- 

 don fails in this regard, and Hadrosaurinae is suggested as a prefer- 

 able term. The genus Hadrosaurus was most probably a non-crested 

 form, reliance being placed on the evidently pointed termination of 

 its ischium. It is impossible to state whether Trachodon was a 

 crested or non-crested form. 



Adopting these subdivisions of the Hadrosauridae, the genera 

 of which the structure of the head is best known may be grouped as 

 follows, with the earlier types of the Belly River formation first: 



Hadrosaurinae. Saurolophin^. 



Gryposaurus Lambe, Belly Stephanosaurus Lambe, Belly 



River. River. 



Edmontosaurus Lambe, Edmon- Prosaurolophus Brown, Belly 



ton. River. 



Kritosaurus Brown, Horizon un- Corythosaurues Brown, Belly 



certain ? = Edmonton. River. 



"Claosauous" Marsh, Lance. Saurolophus Brown, Edmonton. 



Diclonius Cope, Lance. Cheneosaurus Lambe, Edmonton 



Hypacrosaurus Brown is a genus from the Edmonton formation 

 of Alberta. It's skull, as yet unknown, will probably be found to 

 be crested as the ischium is expanded distally into a "foot." Like 

 Hadrosaurus its assignment to a subfamily depends at present on 

 the shape of the ischium. Hypacrosaurus is stated by Brown to 

 also occur in the Belly River formation of Alberta. 



The complete skeleton of a large hadrosaur from the Lance 

 formation of Dakota, now mounted in the American Museum of 

 Natural History, New York, and referred to generally as Diclonius 

 mirabilis, was described by Cope, under this name, in 1883, with 

 special reference to the cranial characters. 



Cope identified this Lance species with Trachodon mirabilis of 

 the Judith River beds, substituting the name Diclonius for Trachodon 

 on the supposition that the latter had been abandoned by Leidy. 

 Cope, prior to this, had described three species of Diclonius D. 

 pentagonus, D. perangulatus, and D. calamarius without figures, 

 from shed teeth from the Judith River formation, which teeth are 

 stated to be no longer identifiable in the Cope collection. It would 

 seem to be best, therefore, in the interests of palaeontology, to dis- 

 continue the use of these three specific names. 



