Number 82 April 28, 1920 



OCCASIONAL PAPERS OF THE MUSEUM OF 

 ZOOLOGY 



UNIVERSITY OF MICHIGAN 



Ann Arbor, Michigan Published by the University 



ON A VERY PERFECT THORACIC SHIELD OF A LARGE 

 LABYRINTHODONT IN THE GEOLOGICAL COLLEC- 

 TIONS OF THE UNIVERSITY OF MICHIGAN 



By E. C. Case 



Remains of the large Labyrinthodonts of Triassic age are known 

 from many localities within the United States, but very few speci- 

 mens are more than fragments and reveal little of the anatomy. 

 Branson {Jour. Geol., XIII [1905], 568-94) has summarized the 

 known material up to the date of his paper. In the summer of 

 1919, while examining the Dockum beds in western Texas, the 

 author collected the nearly perfect clavicles and interclavicle 

 (epistemimi) of a large form. As shown in the accompanying 

 photograph, the plates are in such a perfect state of preservation 

 as to show all the details of the lower surface. Only the extreme 

 tips of the slender processes of the anterior ends of the plates and 

 the scapular processes of the upper surface are lost. 



The interclavicle is rhomboidal in form with the center of 

 ossification and sculpture in the posterior half. The clavicles 

 articulate with the interclavicle by overlapping suture at the 

 posterior end; the contact was preserved by strong ridges and 



