LITERARY NOTICES. 



271 



out the facts, whatever theories they might 

 favor ; but he could not be insensible to the 

 import of his labors. 



Some idea of the immense value of Pro- 

 fessor Marsh's contributions to paleontology, 

 as well as the immense labor that they have 

 cost, may be gathered from the fact that 

 in the last twelve years he has enriched the 

 museum of Yale College alone with about 

 one thousand new species of extinct verte- 

 brates, at least one half of which remain to 

 be studied out and described. That which 

 is remarkable about these collections is the 

 excellence of their preservation, and the 

 profusion of specimens by which it becomes 

 possible to restore nearly completed skele- 

 tons. Paleontologists have hitherto had to 

 work much from fragmentary specimens ; 

 but Professor Marsh is now enabled to re- 

 store the extinct vertebrate forms of the 

 Western Cretaceous beds with such fullness 

 of detail as seriously to affect the literary 

 treatment of the subject. His large memoirs 

 will be confined to a few restorations, but 

 the work in each case will be a finished con- 

 tribution to which little can ever be added. 



The present memoir on " Extinct Toothed 

 Birds " is his first systematic publication on 

 the Western fossils, and forms Volume VII 

 of the " Geological Survey of the Fortieth 

 Parallel," conducted by Mr. Clarence King ; 

 and it also forms Volume I of " Memoirs of 

 the Peabody Museum of Yale College." In 

 regard to its contents, we can not do better 

 for our readers than to reproduce the fol- 

 lowing extract from a notice of it in " Na- 

 ture," by Professor Geikie, the able head of 

 the Geological Survey for Scotland : 



Among the organic wonders of which from 

 time to time during the past decade announce- 

 ments have appeared, none have been received 

 with more interest than the discovery of birds 

 with teeth, made by Professor Marsh near the 

 end of the year 1870, in the middle Cretaceous 

 rocks, which in Kansas and Colorado spread out 

 eastward from the base of the Rocky Mountains. 

 So perfect a matrix do the peculiar buff, chalky, 

 or marly beds of the Kansas middle Cretaceous 

 formations furnish for the preservation of or- 

 ganic remains, that almost every bone of the 

 skeletons of some of the birds has been recov- 

 ered. The material for the study of their oste- 

 ology is thus almost as ample as that for any liv- 

 ing bird. Full advantage of this abundant store 

 of material has been taken. The cases and cel- 

 lars in the Peabody Museum at New Haven con- 

 tain the remains of about fifty different individu- 

 als of a single bird. Every bone of its skeleton, 



with the exception of one or two terminal toe- 

 bones and the extreme point of the tail, has 

 been recovered, and is here carefully drawn of 

 the natural size. Never before has it been pos- 

 sible, we believe, to reconstruct so perfectly so 

 ancient an organism. 



The volume is divided into two parts. In 

 the first of these the detailed structure is given 

 of the bird on which the author has bestowed 

 the name of Hisperornis. The skeleton of this 

 animal if extended to its full length would mea- 

 sure about six feet from the point of the bill to 

 the end of the tail. It must have been a typical 

 aquatic bird, without any power of flight, but 

 with strongly developed limbs and a long, flexible 

 neck, whereby it was doubtless endowed with 

 remarkable powers of diving and swimming, 

 and of seizing the abundant fishes of the shal- 

 low seas in which it lived. Compared with our 

 modern birds, the two features of this ancient 

 form which most forcibly arrest attention are 

 the teeth and the legs. The teeth were covered 

 with smooth enamel, terminating upward in 

 conical pointed crowns and downward in stout 

 fangs, closely resembling those of mosasauroid 

 reptiles. Their mode of growth and replace- 

 ment have been determined to have taken place 

 in a manner very similar to that in some rep- 

 tiles, the young tooth forming on the inner side 

 of the fang of the tooth in use, and increasing in 

 size, while a pit for its reception was gradually 

 made by absorption. The old tooth, being pro- 

 gressively undermined, was finally expelled by 

 its successor, the number of teeth thus remain- 

 ing unchanged. The teeth were implanted in a 

 common alveolar groove, as in Ichthynsavrus. 

 In the upper jaw they were confined to the max- 

 illary and entirely absent from the pre-maxillary 

 bone ; in the lower jaw they extended from near 

 the anterior extremity of ther.amns along the 

 entire upper border of the dentary bone. Mr. 

 Marsh believes that they were held in position 

 by cartilage which permitted some fore-and-aft 

 movement, but on the decay of which after death 

 the teeth readily became displaced and fell out 

 of the jaw. This is an important fact in its 

 bearing upon the nature of the teeth fotind on 

 the same slab of Solenhofen limestone with 

 the well-known Archaopteryx. These teeth, it 

 will be remembered, were referred by Mr. 

 Evans to the bird itself a reference fully 

 confirmed by Mr. Marsh, who says that he at 

 once identified the teeth as those of birds and 

 not of fishes, and by the subsequent discovery 

 of other remains of the bird. In Hespernrnis re- 

 gnlis there appear to have been fourteen func- 

 tional teeth in the maxillary bone, and thirty- 

 three teeth in the corresponding ramus of the 

 lowerjaw. The wings are rudimentary or abort- 

 ed, a remnant of the hiimenis alone existing. 

 They may have gradually diminished from dis- 

 use until, as the power of flight ceased, the legs 

 I and feet increased in proportion, and assumed 

 ; the massive dimensions shown in these speci- 

 I mens, or, as Mr. !Marsh suggests, the bird may 

 I have been a carnivorous aquatic ostrich, never 

 i having possessed the power of flight.but descend- 

 ed from a reptilian ancestry, which is strongly 



