26 



NATURAL HISTORY OF BIRDS. 



tially as in liviiij; Mrtls, as a|>parently was the sternum also. Of the clavicles only a 

 fi"it;nu'nt of the ii|i|>ei- eml lias yvt hcvu fuuntl. The win^rs dearly imlicati' very 

 Ktrony jiower of tlii;!it. The hiiinerus hail an enormous raiiial crest, sur|iassini; in 

 conijiarativc size that of any living; hinl, and was placed in a jilano nearly jiarallel with 

 the liini; axis of the head of the humerus, instead of considerahly indiiied, as in most 

 liinls, thus stronitly resemliliui;, in these two points, the humerus in the pterodactyls, 

 the extinct flyinjj reptiles. The carpal bones were two in number, anil the metacar- 

 pals united as usual ; a noticeable feature of the .second lini;er is that the thin lateral 

 expansion of the tii'st |>halanx ends in a |irominent flattened, hook-like jirocess beyond 

 the rest of the bone. 



The pelvic arch exhibits some interestiuii reptilian characters. The sacrum con- 

 sisted of about ten vertebra? thoroujihly anchylosed, as were also the jielvic bones. 

 Of these the ischium w:is expamled in the middle, extended further back th:ui the 

 ilium, and was not united with the latter )iosteriorIy, agreeing in that res]iect with 

 Jlcsjjcrornis and a few modern reptilian birds. The legs an<l feet do not differ more 

 from those of modern birds than did the wings. The metatarsals are anchylosed 

 lirndy and ]ircscnt no peculiar features. The phalanges, with the exception of one, 

 have not yet been found. 



That Lhl/ii/iiniia was j)rovided with feathers is proved beyond i|Ucstion by the 

 tubercles for the attachment of quills on the forearm. It will tiius be seen that Ich- 



Fiu. 10. 



Kl<!. II. 



VertebriB nf Ichthyomii. 



Fm. 12. 



t/ii/oniis, " the lisli-bird," as it is fitly called from its fish-like vertebra', was a remarkable 

 combination of very old and very modern characters, biconcave vertebra* and large head 

 with separate lower jaw and teeth, in connection with ani-hylosi'd metacarpals ami 

 metatarsals. Heferring to the accompanying cut (Fig. 0), which rejiresents ."Marsh's 

 restoration of one of the species, for information eoncerning the general aspect of the 

 bird, we may remark, however, that the missing parts .are supplied from a tern, a rather 

 specialized modern bird, and that conseiiuenlly many features of the restoration :n'e 

 unreliable, while one, at least, is manifestly incorrect. For we may safely a.ssuine that 

 Ic/it/ii/ornls was holorhin.al like Ilesperoniin, .and not schizorhinal like a tern, as re])re- 

 .sented in the figure, and it seems rather strange that the head has been restored after 

 the fashion of the latter, when it is admitteil that it resembles that of the former 

 " more nearly than that of any other known bird." We may, jierhaps, also take exce|v 

 tion to the restoration of the neck, as not in harnionv with the dispro])ortionate large 

 head. 



The gap between Ic/if/ii/or/ti.s and all other birds is very great, so it would be ijuite 

 unsafe to advance any o|iinion as to its genesis .ind relationships. All that we can say 

 at present is, th.at it spnmg very early from the ancestral stock, |)reserving the jirimi- 

 tive char.acter of the verlebriv; and the skull long after other jiarts had reached an 

 advanced specialization, thus adding new evidence to the principle, " that au animal 

 m.ay attain great development in one set of characters, and at the same time retain 

 other low features of the aucestr.al type." 



