no 



KNOWLEDGE 



[Apeil 1, 1890. 



however, that bone is eitlier rudimentary or absent in the 

 flightless birds allied to the ostrich, it cannot be regarded 

 as a feature of first rank in distiiiguisliing Ptci'odactylcs 

 from birds. 



Having thus shown that our Flying Ih'agons cannot be 

 classed witji l)irds, it remains to nu'ution why they should 

 be placed with reptiles rather than with nuuumals. Tliis 

 point is, however, at once decided by the circumstance 

 that the skull is jointed to the back-bone by a single knob- 

 like articulation, or condyle, instead of by the two con- 

 dyles found in all mammals. If further proof were 

 wanting, it is found in the circumstance that each half of 

 the lower jaw consists of several totally distinct bones, as 

 in all birds and reptiles ; whereas in mammals it is 

 composed of but a single piece. 



^Vith this glance at the general features of the skeleton 

 of the Flying Dragons, we may proceed to notice some of 

 the peculiarities of the different kinds of these creatures, 

 and also what is known as to the structure of their wings. 

 The true Pterodactyles, as is shown in Fig. 1, are readily 



. — Rkstoiiation of a L(ing-taii,ki> Fi-ving Dr.AGON, nit RiiAMr 

 Oiio-seventh natuial size (Aftor Jlarsli.) 



characterised by the extreme shortness of the tail ; but in ' 

 another group, also found in the Lithographic limestones, 

 the tail is as long as that of a lizard. The members of 

 this second group are known as liham[)horhyuehs, and the 

 restoration show n in Fig. 2 is taken from a beautiful example 

 found some few years ago, in whith tlie impression of the 

 delicate membrane of the wing is iireservod with as mucli 



enough, a slab of Lithographic limestone preserved in the 

 museum at Haarlem exhibits a sinuous trail which is 

 believed to have been caused by the extremity of the tail 

 of one of these creatures as it walked across the soft nmd 

 now consolidated into stone. The impression of the 

 wings shows that these consisted of a soft leathery mem- 

 brane, probably something like that of the wing of a bat ; 

 and it is (piite evident that there were no feathers either 

 on the body or on the wings. The body, like the wings, 

 was, indeed, in all probability entirely naked ; and this cir- 

 cumstance militates agai-nst the suggestion that the Flying 

 Dragons were warm-blooded creatures, since a protection 

 of either fur or feathers is fomid necessary in the case of 

 birds and bats to maintain their high temperature. The 

 Ehaniphorhynchs occur not only in the Lithographic 

 limestone, which is situated near the top of the great 

 Oohlic system — the system underlying that of tlie Chalk 

 — but are also found in the much older Lias. Another 

 group, also found in the Lias, are characterised by their 

 short skull and the superiority in size of the front over the 

 hinder teeth, in consequence of which they 

 are known as Dimorphodouts. 

 ■ ---.^ Perhaps, however, the most remarkable 



-^--^^:^ forms found in the whole group are the tooth- 

 less types, or Pteranodonts, of which a skull 

 is shown in Fig. 3. In these creatures teeth 

 were totally wanting, and the jaws were pro- 

 bably sheathed in horn, like those of the 

 tortoises (see Knowledge for January), while 

 the hinder or occipital regioir of the skull was 

 pro<luced into an enormous flattened spine, 

 which also recalls a feature found in the tor- 

 toises. Whereas most of the forms we have 

 hitherto noticed did not exceed a rook in size, 

 iiciHiivNeii. some of the Pteranodonts were of enormous 

 dimensions, one of them having a skull mea- 

 suring upwards of four feet in length, and its 

 expanse of wing being probably about twenty-five feet. 

 These Pteranodonts are foimd in the chalk of the United 

 States; but species nearly as large occur in the chalk of 

 this country, although they were furnished with a powerful 

 armature of teeth, and have been described under the 

 uncouth and exceedingly misleading name of Ornitho- 

 chirans — the hand or wing of all the Flying Dragons 



Fig. :?.— Left Side of the Skui.l of a Toothless Flying Dkagox, ok Ptkuanouont. One-sixth natural size. a. Vncuily in 

 front of the eye ; h. Socket of the eye ; c. Occipital spine ; d. Angle of lower jaw ; e. Extremity of upper, and e. of lower jaw ; </. Articulation 

 of the skull proper with the lower jaw ; s. Points where the two branches of the lower jaw diverge. (After Marsh.) 



sharpness as if made but yesterday. This and other 

 specimens show that while the front edge of the wing was 

 supported by the elongated finger, the wing extended 

 backwards to embrace the greater part of the hind limb, 

 whOe the extremity of the tail was furnished with a 

 racquet-shaped expansion of membrane which probably 

 served the purpose of a rudder during flight. Curiously 



being, as we have already said, as much unlike that of a 

 bird as it well can be. These huge monsters flying through 

 the air must have been a marvellous sight, and they afford 

 one more instance that the wildest dreams of romance 

 have not produced creatures one wit more wonderful than 

 those which at one time had a corporeal existence upon 

 the earth. 



