The foUoffiiL' 



TIlANiiAfTIO.NS Of {SECTION I). 



76:i 



*X On the Clasaljicdtion and Affinitins of Duionanrlan Hcj^tilcn. 

 liij I'rofossor O. C. AIausii. 



'J'lit' niitlKir prest'iitt'd lirit'lly tilt' result.- .if a study of Hiiumniiviiiii N'lililcs mi 

 ^vhich III' liiul liccii t'ii^'aj,'f<l for soviTal yt'uis. 'J'lic ('(iinplt'tr rrsiilts will 1)(> piili- 

 \\Aw(\ ill (V serii's of inoiioj;riii)li8 now in |ii'i'|iiiriition. 'liic niiiti'ria! on wiiii-h tln' 

 i:ivt'>ti;.'iiti()n ii mainly Imsfd consists of tliH reujains of scveriU luinilri<l individuals 

 1)1 ibis ^.Tonp colU'ctcfl in tlin Kocliv Mountains by the author, an<i now jircserved 

 i;i till) .Mii't'iiin of 'N'ali' ( 'olltyt', 



UiliiT ini])ortaiit American specimens have Iwen examined b\ e nutlior, who 

 iias also studied witii care tlie more important remains of th. ^roup in the 

 niiiseunis of Kuroj.'. The investiiration is not vft completed, hut the results 

 Hlremly attaiiied setm to be of suilicifut inteiest to present to tlie Assoeintiou 

 at this time. 



In previous publicationa on this sulijeet, the autlioi' had expressed the oj)inion 

 (hilt tlif J)iiiiiKiiii,ri(i should bf reirarded, not as nil (U'der, but as a hiih-clHss, and 

 Lis later researches confirm this view. 



Tlie yreat number of Bubordinate divisions in the ^'I'oiip, and the renmrhaide 

 divfi'sity amoiifr those already discovered, indicate that many new forms will yet 

 l«> round. Ainoiifr those already known there is a much ;rreater dillerenee in ^i/e 

 1111(1 Htnirtui'e than in any other sub-class of vertel)rates, with the exception of the 

 ]ilacriitiil maiunuds. Compared with the .Marsupials, Ii\ iii^-- and extinct, the ])ino- 

 Miuria show an etpuil diversity of structure and size. 



Accordinijr to ]n-esent evidence, the Dinosaurs were confined entirely to the 

 Me.''OZiiic' aye. They were abundant in the Jurassic, and continued in diminishiiiii' 

 inMubers to the end of the ( 'retaceoits peiiod, when they became extinct. Tin; 

 <:rfat variety of form.s that tlouri.died in the Tria.s.sic renders it more than probable 

 that .some members of the fri'oup exL-^ted in the I'ernuan period, and their remains 

 may he l)rought to lijrht at any time. 



The 'J'riassic Dinosanrs, althoui:h very numerous, arc known to-day mainly 

 fi'imi fuotjirints and fraf^nieiitary o.s.seous remain.s; hence, numy of the forms de- 

 .•■crilied cannot at jjresent be referred to their ajipropriato divisions in the 

 group. 



From the Jura.ssic, however, duriiifj' whicli period Kinosaurian reptiles reached 

 tlieir zenith in size and numbers, representatives of no less than four well-marked 

 ordfi-s are now .■^o well known that diflt'rent families and ^nMiera can be vt ry 

 aciurately determined, and almost the entire osseous structure of typical examples, 

 at least, can be made out with certainty. 



Comparatively little is yet known of Cretaceous Dinosaurs, althoujjrh many have 

 li'cii described from incomplete specimens. All these appear to have been of lar)j:e 

 .>izt', but much inferior in tins respect to the jji^antic forms of the previous ])eriod. 

 Till' remains best preserved show that, before extinction, some members of the 

 j-'roiip became cpiite hi^rhly specialised. 



Itei^arding the Dinosaurs as a sub-class of the Jicptilia, the forms best known 

 a! present may be classified as follows : - 



Sub-Class DiNosAURiA. 



Premaxillary bones separate; upper and lower temporal arches ; rami of lower 

 jiiw united in front 1)V cartilajre only ; no teeth on palate. Neural arches of verte- 

 brie uniteil to centra by suture ; sacral vertebrte coiissitied. Cervical and thoracic 

 viljs double-headed. Ilium pvoiono-ed in front of acetabulum ; acetabulum formed 

 in part by pubes ; ischia meet distally on median line, lore and hind limits present, 

 tlie latter ambulatory and larger than those in front ; head of femur at vijjht an;;-les 

 to condyles; tibia with procneinial crest; fibula ct)inplete. Fir.st row of tarsals 

 compn.sed of astragalus and calcaneum only, wdiich together form the upper portion 

 of ankle joint. 



I. Order Sauropoda (Lizard-foot). Herbivorous. Premaxillary bones with 

 teeth. Large antorbital opening. Anterior nares at apex of skull. Post-occipital 

 bones. Anterior vertebrte opisthoccelian ; cervical ribs coossified with vertebrae ; 



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