545 



®i[ijginal guiti^les. 



XLIX. — Upon the Episterxal portions of the Skeleton, as 

 THEY appear IN Mammalia AND IN Man. By C. GegenbaupT.* 



Under the name of Episterual bones those portions of tlie skeleton 

 are indicated, wbicli presenting well marked characters in Amphibia 

 (Frogs), and in Eeptiles (Lizards and Crocodiles), exist only in a 

 fragmentary condition, and with modified relations in Mammals. In 

 the Seals these bones are merely applied to the anterior extremity 

 of the sternum ; in the Armadilloes they constitute detached bones of 

 more importance, lying in front of the manubrium sterni, and con- 

 nected by a ligamentous bond of union with the sternal ends of the 

 clavicles ; and in the Monotremata they form a single T-shaped bone 

 placed in front of the sternum, with the transverse or outrunning 

 arms superimposed for a certain distance on the anterior clavicular 

 bones.f 



In all these instances then, there are portions of the skeleton 

 which effect a connection between the sternum and the anterior 

 clavicular bones : except of coiu-se in the Seals, in w^hich no clavicles 

 are developed. Now, in some instances these portions of the bony 

 framework of the body are symmetrical in their arrangement, in 

 others they are asymmetrical or azygous, and they consequently 

 present many varieties of external form. Our knowledge of the 

 existence of these and similar episternal structures in other divisions 

 of the mammalia besides those abovementioned, has hitherto been 

 extremely limited, J and though structures resembling those normally 



* Translated from the original in the " Jenaische Zeitschrift fiir Medicin," &c. 

 vol. I. (1864) p. 175, et seq. 



f Cuvier, Recherchcs sur les ossemens fossiles 4e Edit. T. viii, 1, p. 252 ; and 

 Leyons sur I'anatoniie comparee 2e Edit. T. 1, p. 238 ; Stannius, Lehibuch der 

 vcrgleich. Anatomic, S. 349 ; v. Eapp. Anatom. Untersuch. iiber die Edentaten. 

 2 Auflage, Tubingen, 1852, p. 39. 



J In the Cliluiinjdopliorns, an animal which is closely allied to the Armadilloes, 

 the clavicle, according to Hyrtl, is connected with the sternum by means of a liga- 

 ment. Here, as Hyrtl remarks, the relations are the same as in Basi/pus, except 

 that a bony nucleus is absent. See Chlamydophori truncati cum Dasvpode gymnuro 

 comparatum examcm anatomicum. Vienna, 1855, S. 23 (Denkschrift. der Wiener 

 Akad. Band, ix, der Mathemat phys. Classc. ) 



