IB 



STREPTOSPONDYLUa 



8TRIQ1D.E. 



!*) 



(lias shale) near Whitby (much more complete than the preceding 

 (women, and nearly corresponding in size with the doraal vertebra 

 of the ttoufour Streplatpuxdyliu described by Cuvier), in the collectiou 

 of Mr. Kipley of Wbitby ; and informs ui that the third British forma- 

 tion in which he has determined the remains of the genus is the 

 Wealden, specimens baring been obtained from three localities, 

 namely, Tilgate Forest, in Sussex, and Brook Point and Culver Cliff, 

 in the Isle of Wight The specimens, he observes, differ in size, being 

 larger than the Slreptoipondylvt Cmrieri from the Oolite, and he 

 strongly suspects that they indicate a different species; indeed ho 

 names it Ktreptotpondylta major, but remarks that the means of com- 

 parison for the satisfactory establishment of the distinction are aa yet 

 wanting. Professor Owen also makes mention of a cervical vertebra 

 associated, as in the Mantellian Collection, with vertebras of the 

 Jyuancxlox and Cetiotauriu, which had been washed out of the ub- 

 marine Wealden beds at the south uide of the Isle of Wight, and 

 thrown on shore near Culver Cliffs and Brook Point. Some idea of 

 the size of this reptile may be derived from Professor Owen's admea- 

 surements, which give 5 inches as the transverse diameter of the 

 posterior concave articular surface in the Wealden, and 6 inches in 

 the Culver Cliff specimen, whilst the transverse diameter of the body 

 across the inferior transverse processes is 6 inches in the Tilgate, and 

 6 inches 6 lines in the Culver Cliff specimen, the height of the latter 

 from the lower surface of the centrum to the hind part of the base 

 of the spine being 7 inches 9 lines. 



The foreign localities in which remains of Strci>totpondylut have 

 been found are the Oxford clay formation at Houtleur, and the 

 Kimmeridge clay at Havre (Cuvier) ; and the Lias of Altdoi f (H. You 

 Meyer). 



The form of this extinct Saurian is highly interesting, for it pro- 

 Rents those transitional characters which, while they beautifully mani- 

 fest the passage, so to speak, from one specific form to another, are too 

 apt to lead a superficial observer to wild speculations. Professor 

 Owen, in his luminous argument at the close of the valuable Report 

 above quoted, against the transmutation theory fallacy, we would 

 venture to call it of Haillet, Lamarck, the less learned author 

 of the ' Vestiges of the Natural History of Creation,' and their fol- 

 lowers, observes that if the three forms of extinct Saurions, Ichthyo- 

 faunu, Plaiotaurtu, and Teleotauriu, whose changes of specific and 

 generic characters have thus been speculated upon, had actually 

 succeeded each other in strata successively superimposed in the order 

 here set forth, some colour of probability might attach itself to this 

 hypothesis, and there would be ground for searching more closely into 

 the anatomical and physiological possibilities of such transmutations. 

 Those genera however, he observes, appeared contemporaneously on 

 the stage of vital existence ; one neither preceded nor came after the 

 other. How the transmutation theory is to be reconciled to these 

 facts is not, he justly observes, obvious, nor to these other, namely, 

 that the Teleosaur ceases with the oolite, while the Ichtbyosaur and 

 Plraionur continue to co-exist to the deposition of the chalk, and 

 disappear together alike unchanged ; the Ichthyosaur manifesting as 

 little tendency to develop itself into a Pleaiosaur as this to degrade 

 itself into the more fish-like form of the Eualiosaurian type. 



"If," says Professor Owen, "it were urged that the Streptotpondylui, 

 or crocodile with ball-and-socket vertebra, of which the remains 

 occur in later secondary strata, when the Teleosaur hod ceased to 

 exist, might be a modification of the apparently extinct Amphicwlian 

 Crocodile, in which the vertebra) had undergone a progressive develop- 

 ment analogous to that by which the biconcave joints of the vertebra: 

 of the tadpole are actually converted into the ball-and-socket joints 

 of those of the mature Frog, the facts of both geology and anatomy 

 again oppose themselves to such an hypothesis ; for the remains of the 

 tUrtptofpmdytia occur likewise in the Whitby Lias, which is the 

 earliest formation characterised by remains of the Teleotauriu ; and 

 the modification of the vertebral structure by which the Streploipm- 

 dylut differs from its ancient contemporary, anil which it retain* 

 unaltered throughout the whole series of oolitic strata, is no approxi- 

 mation to the ball-and-socket structure of modern crocodiles, which 

 first appears in the Uouuaurtu and the Eocene Crocodiles, but is the 

 very reverse. Aa reasonably might we infer that the Teleosaur was 

 an intermediate form between the Xtreptotpondyliu and modern 

 crocodiles, and that the anterior ball had first subsided, and a sub- 

 bicoooave type of vertebra) had been produced before the posterior 

 ball which characterises the vertebra of recent crocodiles was finally 

 developed. If the present species of animals had resulted from pro- 

 gressive development and transmutation of former species, each class 

 ought now to present its typical characters under their highest 

 recognised conditions of organisation ; but the review of the charac- 

 ters of fossil reptiles taken in the present Ueport proves that this is 

 not the ease. No reptile now exists which combines a complicated 

 and thecodont dentition with limbs so proportionally large and strong, 

 having such well-developed marrow-bones, and sustaining the weight 

 of the trunk by synchonrlrosia or anchylosis to so long and compli- 

 cated a sacrum, as in the order Dinotauria. The Megalosaurs and 

 Ifcnanodons, rejoicing in these undeniably most perfect modification* 

 of the Reptilian type, attained the greatest bulk, and must have 

 played the most conspicuous parts in their respective characters as 

 Uevourers of animals and feeders upon vegetables that this earth has 



over witnessed as oviparous and cold-blooded creatures. They were as 

 superior in organisation and in bulk to the crocodiles that preceded 

 them as to those which came after them." 



There is not the slightest ground for affirming that the procoolian 

 gavial of the present day is in any respect more highly organised than 

 the opisthocoelian gavial of the oldest lias. If the differences of verte- 

 bral structure in these crocodilians were contrasted in reference to 

 their relative approximation to the vertebral structure of the higher 

 animals, the resemblance of the ball-and-socket joints of the spine of 

 the Streptatpondylut to those of certain mammals would give precedence 

 in organic perfection to the primaeval guvial. If therefore the extinct 

 species, in which the Reptilian organisation culminated, were on the 

 march of development to a higher type, the Mcyaloiauriu ought to 

 have given origin to the carnivorous Mammalia, and the herbivorous 

 should have been derived from the Jguanodon. " But where is the 

 trace of such Mammalia in the strata immediately succeeding those 

 in which we lose sight of the relics of the great Dinosaurian Reptiles ; 

 or where indeed can any mammiferous animal be pointed out whose 

 organisation can by any ingenuity or licence of conjecture be derived, 

 without violation of all known anatomical and physiological principles, 

 from transmutation or progressive development of the highest rep- 

 tiles? If something more than a slight inspection be bestowed upon 

 the organic relics deposited in the crust of the globe, we learn that 

 the introduction of Mammalia on that crust is independent of the 

 appearance of the highest forms of reptiles. The small insectivorous 

 mammals of the lower oolite are contemporary with the most ancient 

 Dinotauriu, and are anterior to the Iguanodon. The period when the 

 class of reptiles flourished under the widest modifications, in the 

 greatest number, and of the highest grade of organisation, is passed ; 

 and since the extinction of the Diuosaurian order it has been declining. 

 The lieplilia are now in great port superseded by higher classes. 

 Pterodactylea have given way to Birds ; Megaloaaura and Iguanodons 

 to carnivorous and herbivorous Mammalia ; but the sudden extinction 

 of the one and the abrupt appearance of the other, are alike inexpli- 

 cable on any known natural causes or analogies." (Owen.) 



STKEPTOSTACH Y S. [0 BAMIN ACILE.] 



STRIQATELLA. [VOLUTIDJS.] 



STRI'GID^E, a family of Birds, including the Nocturnal Birds of 

 Prey commonly known as Owls. 



This natural family have large heads and great projecting eyes 

 directed forwards, and surrounded with a circle or disc (more or less 

 developed according to the nocturnal or comparatively diurnal habits 

 of the species) formed of loose and delicate feathers ; a raptorial beak ; 

 crooked claws ; and a downy plumage, generally spotted, powdered, or 

 barred with different shades of brown and yellow. 



Hr. Yorrell, in his paper on the ' Anatomy of Birds of Prey' ('Zool. 

 Journal,' vol. iii.), points out the diminished extent of surface and 

 power in the sternum of the Owls as compared with that of the Pure- 



Sternum of Wood-Owl (Strix Stridulo). ( Yarrell.) 



grino Falcon. [FAI.COMD.E.] And he observes, that from the loose 

 and soft nature of the plumage in these birds, an well as their deficiency 

 in muscle and bone, rapid flight is denied them as useless, if not 

 dangerous, from the state of the atmosphere at tho time they are 

 destined to seek their food ; but, be adds, they are recompcmed for 

 this loss, partly by their acute sense of hearing, from an extension of 

 the posterior edge of the cranium forming a conch, coupled with a 

 very large external orifice ; and partly by the beautifully serrated 

 exterior edge of the wing primaries, which, allowing them to range 

 without noise through the air, enables them to approach unheard 

 their unsuspecting victim, which falls a prey to the silent flight and 

 piercing eye of an inveterate enemy. Ho further remarks, that some 

 increase and variation will be found in the strength and form of such 

 of the Owls as depart from the type of the true nocturnal bird. In 

 tli Snowy Owl and Short-Eared Owls, which are described a.i occa- 

 sionally taking their food by day, the furcula, Mr. Yarrell observes, is 

 stronger and less angular in proportion than in the Wood- and Barn- 

 Owls. The trachea, he tells us, of the different species of Owls so 

 nearly resembles the same part in the Falcons, that a separate descrip- 

 tion is unnecessary, and the same may be said generally of the oeso- 

 phagus, stomach, and intestines, aa the similarity of food would appear 

 to require. Mr. Varrell found the two crccal appendages considerably 

 developed in tho species of Strix ; in the Barn-Owl (S. flammeu), na 



