30 



♦ KNOWLEDGE 



[Nov. 11, 1881. 



BIRDS WITH TEETH. 



IN the year 1861 a feather was found in a slab of litho- 

 graphic .stone from Solenhofen, which Hermann von 

 Meyer assigned to an animal as yet not otherwise known, 

 which he called Arcli(ioj)l<:r)/x litlingraplika. Later in the 

 same year, a large portion of the skeleton of Archjpopteryx 

 was discovered in the same formation. There were im- 

 pressions of feathers radiating fanwise from each of tlie 

 forelimbs. But Prof. Andreas Wagner, in a report to the 

 Royal Academy of Sciences in Munich, e.xpressed the 

 opinion that the creature was not a bird, but a reptile, 

 whoso natural covering presented a deceptive resemblance 

 to feathers. He called it the Griphosuvrus, which (con- 

 sidering he had not seen the fossil remains) was very 

 obliging on his part. Yon Meyer, however, regarded the 

 impressions as representing real feathers, belonging to 

 the same animal as the feather he had already dis- 

 covered. The fossil was secured for the British 

 Museum in 1862. It is contained in two slabs of 

 Solenliofen limestone ; one representing the surface of 

 tidal mud on which the bird lay at the time of its death, 

 the other the layer deposited over the dead body. The 

 lower slab shows the impressions of the tail, wings, and 

 parts of the skeleton. The right shoulder-blade and upper 

 arm (wing), as well as both the forearms, are well preserved. 

 The head, the neck, and the backbone are wanting. Two of 

 the digits of the wing (wing fingers we may call them) are 

 free, and anned with sharp claws or recurved spurs. The 

 right lower limb is well preserved, consisting of the thigh- 

 bone, the tibia or larger lower leg-bone, and the tarso- 

 metatarsal bones, or bones of the upper foot. To the me- 

 tatarsus, four toes are articulated, one hind-toe and three 

 fore-toes, which are jointed as with birds, and amied with 

 strong recurved claws. " The foot," says Mr. Woodward, 

 from whose description tlie above has in the main been 

 taken, " agrees well with that of a true perching bird, but 

 from the fanwise and rounded arrangement of the wing- 

 feathers, it would appear to have been a bird of feeble 

 flight." 



Without entering further into the peculiarities of this 

 creature, we note that while a few naturalists were doubt- 

 ful as to its being really a bird, the majority were very 

 confident that it was so. Professor Owen, in particular, 

 pointed out that in one respect in which it difle.red 

 most from modem birds it resembles the embryonic bird. 

 Its tail-bones diminished gradually to the last, whereas in 

 modem birds, the last vertebra of the tail is almost always 

 the largest. But, said Owen, " AU birds iu their embryonic 

 state e.xhil>it the caudal vertebra distinct, and in part of 

 the series [of embryonic changes] gradually decreasing in 

 size to the pointed end one." The two-fingered and free 

 condition of the wing-hand, that is of what corresponds to 

 the hand in the bird's fore-limbs (which Owen pleasantly 

 descriljcd as the biunguiculate and less confluent condition 

 of the manus), he did not account for in the same way as a 

 feature of an embryonic bird ; but in some modern species the 

 forward wing finger supports a claw, and the Screamer has 

 two claws. All who at that time examined the fossil agreed 

 that in all probability the creature had a beak like a 

 bird. 



But Mr. John Evans noticed somewhat later (besides a 

 rounded mass wliich he took for part of the lirain-pan, with 

 a cast of the brain) what he regarded as a fossil jaw, on 

 the slab on which lies the fossil body of the bird. It had 

 been supposed to be the beak of Archa-ojjteryx, but "great 

 was my surprise," wiitcs Mr. Evans, "when I detected 

 along its right-hand margin, towards the apex, the distinct 

 impression in the slab of four teeth still attached to it. 



The teeth themselves remain adhering to the counterpart, 

 and are easily recognised by the lustre of their enamel" 

 The teeth are thus di'scribed l)y Jlr. Woodward. " Tlie three 

 which remain in a vertical position with regard to the jaw 

 are about one-tenth of an inch long, and at intervals of al»out 

 one-fifth of an inch. They consist of a slightly tapering 

 flattened enamelled crown, alwut a twenty-fifth of an inch 

 in width, and oljtusely pointed, set upon what is apparently 

 a more l>ony base, which widens out suddenly into a semi- 

 elliptical fomi, so that at the line of attachment to the jaw 

 the base of one tooth comes in contact with that of the 

 next. So sudden and extensive is this widening of the 

 base, that at first it gave me the impression tliat the teeth 

 were tricuspidate, with the middle cusp far longer than the 

 others. Tlio front tooth of the four, which slopes forward 

 from the rest, and is rather smaller than the others, shows 

 little, if any, similar enlargement of its base. Of the fifth, 

 which lies across the base of the foremost of the four, only 

 a part is visible. There appears to be a well-defined line 

 at the base of the teeth along their junction with the jaw, 

 but I can ofler no opinion as to the method of their 

 attachment" 



It seemed so unlikely when the above description was 

 %\Titten that a jaw armed with teeth could belong to a 

 creature manifestly bird-like, that many supposed the jaw 

 belonged to some fish, though the jaws and teeth of fossil 

 fishes from the same bed were found to be unlike this. 

 Hermann von Meyer, referring to the drawings sent to 

 him by Jlr. Woodward, said that he knew of no tooth of 

 the kind in the lithographic stone ; nor were the teeth 

 like those of Pterodactyles (the great reptiles with bat- 

 like wngs). " An arming of the jaw with teeth would 

 contradict the view of the Archaopteryx being a bird or 

 an embryonic* form of bird. But, after all," he proceeds, 

 " I do not believe that God formed his creatures after the 

 systems devised by our philosophical wisdom. Of the 

 classes of birds and reptiles, as we define them, the Creator 

 knows nothing, and just as little of a prototype or of a 

 constant embryonic condition of the bird which might be 

 recognised in the Arch^opteryx. The Ai-chaMpteiTx is, 

 of its kind, just as perfect as other creatures, and if we 

 are not able to include this fossil animal in our system, 

 our shortsightedness is alone to blame." 



Probably the theory that the Archaopteryx had teeth 

 would still be regarded as little better than an assumption, 

 had not other and more complete evidence been obtained. 

 Professor Marsh discovered two fossil birds in the creta- 

 ceous shale of Kansas, which had well-developed teeth in 

 both jaws. Of one of these birds — the Jchthyornis 

 Dispar — " the teeth were quite numerous," Marsh 

 wrote in SilHmaji's Journal for October, 1872, "and 

 implanted in distinct sockets. They were small, com- 

 pressed, and pointed, and all of those preserved are similar. 

 Those in the lower jaw number about twenty in each 

 ramus " (that is, on each side), " and all more or less in- 

 clined backwards. The series extend over the entire margin 

 of the dentary " (or tooth-bearing) " bone, the front teeth 

 being very near the extremity. The maxillary teeth " (those 

 in the upper jaw, that is) " appear to have been equally 

 numerous, and essentially the same as those in the mandible. 

 The skull was of moderate size, and the eyes were placed 



well fonvard. The lower jaws are long and slender 



The jaws were apparently not encased in a horny sheath. ' 



• The word embryonic is here used with reference to the species, 

 not to the individual. It signifies a form which creatures of the 

 species presented before the tj-j)e of the species had become, as 

 it were, distinct and established. Traces of such past forms of a 

 species are recognisable in the embryonic development of later 

 representatives of the species. 



[CbfUiRMi on pa^f 33. 



