ODONTORNITHES 651 



phrase of it as a " Swimming Ostrich." About the same time it 

 was found that the presence of teeth was a character apparently 

 common to all " Cretaceous " Birds. The opinions expressed by 

 Prof. Fiirbringer in the earlier portion of his great work need not 

 be here adduced, since they were modified in the course of its pro- 

 gress ; but he finally declared (Untersuchungen, u. s. w. pp. 1543, 

 1565, 1580) that the Odontolcx were the ancestral relations of 

 his " Colymbo-Podicipites," with which they formed his Suborder 

 " Podicipitif ormes," while a similar view was taken in 1890 by 

 Prof. D'Arcy Thompson (Stud. Mus. Dundee, No. 10). 



As to the Odontotormse Prof. Marsh has displayed commendable 

 caution. On account of some similarity, the significance of which 

 may or may not be important, he based his restoration of Ichthyornis 

 on Sterna (TERN), a fact which has led to exaggerated if not mis- 

 taken views, for he was careful to state that Ichthyornis seemed to 

 have points of resemblance to Ardea, Ciconia, Colymbus, Phalacro- 

 corax and even to the Accipitres, while its posterior extremities alone 

 indicated a structure similar to that of the Laridx and Alcidw. In 

 1893 Dr. Gadow (Thier-reich, Vb'gel, ii. p. 119) suggested that the low 

 characters of Ichthyornis shew it to be the beginning of the Carinatx. 



In 1891 the present writer (Cat. Foss. B. Br. Mus. pp. 200 etseqq.), 

 while fully admitting both the Colymbine affinities of Hesperornis 

 and the Larine resemblances of Ichthyornis, proposed to retain the 

 term Odontornithes for a series of Birds ancestral to the modern series 

 of toothless Carinatde, adopting (op. cit. p. 2) for the latter, but in a 

 wider sense, Dr. Stejneger's name (Stand. Nat. Hist. iv. p. 64) of 

 Euornithes. In addition to the presence of teeth, the extinct series 

 differs from the Euornithes by the absence of union between the rami 

 of the mandible, and between the distal ends of the ilium and ischium. 



Whatever may be the ultimate verdict on these points of 

 classification, it would seem probable that Hesperoi'nis should be 

 regarded as an offshoot from the same ancestral stock as the one 

 from which the modern Colymlidse have originated ; such ancestral 

 stock being characterized by the presence of teeth, absence of 

 ancylosis between the mandibular rami, and want of union 

 between the spike-like patella and the upwardly-produced cnemial 

 crest of the tibia. On the other hand, the abortion of the keel of 

 the sternum, as well as the general Eatite modification of the 

 scapular arch, are features peculiar to Hesperornis, and not common 

 to the ancestral type ; being, in fact, nearly analogous to those 

 presented by Didus among the Columbse. The typical species of 

 Hesperornis (H. regalis) was of large size, attaining a length of about 

 six feet ; while a second species (H. crassipes) was still more gigantic. 

 Both were aquatic, and probably very similar in their general 

 habits to the Divers. Probably more or less closely allied to this 

 genus was the much smaller Colymbiform bird from the Cambridge 



