CRETACEOUS PTERODACTYLES. 447 



In no other reptile does the sternum present coracoid articulations so shaped 

 and so placed as in the Pterodactyle. The Crocodilia, in which, as in Pterosauria, 

 the clavicles are wanting, show the broad, sternal mari^ins of the coracoids 

 ligamentarily attached to the middle of the lateral border of the sternum. 



In bats the obtuse, sternal ends of the clavicles are applied to protuljerances of 

 the manubrium above the articulations of the first pair of ribs. Only in birds are 

 distinct synovial articular cavities provided for the coracoids, which, in the main, 

 are situated and shaped as in the Pterodactyle. The ditferences are these : the 

 concavity and the convexity being (as e.g. in Apfcnodjjle^) the same, tlie bent 

 grooves so formed are much longer tiian in the Pterodactyle, with a concomitant 

 greater expansion of the ends of the bones they firmly lodge. The coracoid grooves 

 are divided by a non-articular, median depression in JjjfenoJijfes, but this, in some 

 other birds, is wanting, the coracoid grooves decussating across the middle line, 

 e.(/. in tlie Heron.* There are various minor modifications of the coracoid grooves 

 in the breast-bone of l)irds. 



The marked distinction in the breast-bone of the Pterodactyle is its com- 

 pression behind the coracoid articulations, and the distinct commencement of the 

 shield-like expansion behind that articular part. 



Inmost birds the "manubrium" projects from the mid-space between the 

 coracoid grooves, and is distinct from the " keel ; " in some it is bifurcate ; in the 

 penguins it is as little developed as in the Pterodactyle, and is as directly con- 

 tinuous or connate with the forward production of the keel. In this production 

 Jptenodytes pafachuiiica most resembles, amongst birds, the Pterodactyle. The 

 parts are homologous, and if we name that production the fore part of the keel 

 of the breast-bone in the acpiatic bird, we must apply the same name to it in the 

 Pterochictyle ; only in the latter the keel suljsides sooner beneath the expanded 

 part of the sternum. 



In the Crocodilia the broad, thin, sternal borders of the coracoids are attached 

 by fibrous substance to the fibro-cartilaginous, or, in old animals, partially 



£s besitzeii aber audi die iMaulwiirfc am l)riistl)fiii ilioscu Kiel, der dalier niclit iinbediiij^t als ein Zeichen 

 des FliigveriiK'igeus gelten kanii; cr setzt eigenllich nur starke Brustmuskelu vuraus, die daraii l)el'estigt 

 waren. Selbst in den Schwiinmvugeln die nicbt zii ilie-en vermogen ist der Iviel vorbaiukn fiir starke 



r.riistiiHiskeln, die bier zuiii Scbwimnieii ebeii so iiiitbig .siiid wie deni IMaiilwurt' ziiiii (iiabeii 



Aus diesen lietracbtungeu ergiebt sieb, daNS der I'terodactyliis iiach der IJeseballenlieit seines Brustbeins 

 weder ein eigentlicbes Wassertbier, iiocb ein Giilber war, vitlmebr ein Tiiier der Liift." (' Reptiben aus 

 dem Litbograpbiscben Sebiel'er,' &c., fob, [). 17.) 



Professor Quenstedt, bowever, seems to me to bavc rigbtly appreciated tlic bomology of tlie fore part of 

 tbe sternum and tlie pbysiologieal deductions from it: " IJer Kamm springt vorn einen balben Zoll weit 

 iiber die FUiebe des Kuuebens biiiaus, gibt daber Beweis genug, das das Tbier lliegen konnte." (Op. cit., 

 I'- 11.) 



* Owen, 'History of Briti^b l''(is.-il jMaminals and Birds,' 8vo, KS-IO. p. UUC), fig. 2,'5C. 



•Z r 



