178 LABYRINTHODONTIA. 



teeth on the vomers or middle region of the palate ; in the adult the 

 skull long and triangular, with the orbits in the hinder third, and 

 inclining to one another anteriorly ; and the nares large, ovoid, and 

 placed some distance behind the muzzle. Median thoracic plate 

 long, diamond-shaped, and flattened. Neural spines of vertebrae 

 well developed, without a horizontal expansion at the summits. 

 Four digits in the man us. 



Archegosaurus decheni, Goldfuss \ 



Syn. Archegosaurus medius, Goldfuss 2 . 

 Archegosaurus minor ; Goldfuss 3 . 



The type species. Skull of adult (fig. 43) nearly twice as long as 

 broad, with the orbits of an elongate-oval contour and situated very 

 far back ; in large examples with a length of 0,300 (11*8 inches), 

 but more usually about 0,200 (7*9 inches). 



In the young the skull is considerably wider in proportion to its 

 length, which does not exceed 1| times the width ; the apparent 

 width is frequently much increased by flattening in young specimens. 



Hab. Europe (Germany). 



The following specimens, or their originals, were obtained from the 

 Coal-bearing Shales of the Lower Permian (Rothliegendes) of 

 Lebach and SaarbriicJc, Rhenish Prussia ; those deposits having 

 for a long time been classed with the Carboniferous. 



R. 1741. Cast of the imperfect cranium. The original is the type, 

 and is figured by Goldfuss in his ' Beitr. vorwelt. Fauna 

 d. Stein kohlengebirges,' pi. i. figs. 1-3, nnd also by Meyer 

 in the ' Palseontographica,' vol. vi. pi. xi. fig. 5. 



Purchased. 



R. 1742. Cast of a slab showing the anterior portion of the skeleton 

 of a young individual. Original figured by Goldfuss, op. 

 cit. pi. iii. fig. 1, as v A. medius (of which it is the type), 

 by Meyer, op. cit. pi. xiv. fig. 3, and in Zittel's ' Handbueh 

 der Pakeontologie,' 1 Abth. iii. Baud, 2 Lief. p. 384, 

 fig. 373. The gills remain, and the thoracic buckler is well 

 shown. Purchased. 



R. 1743. Cast of a slab showing the skull, thoracic buckler, and 

 anterior vertebrae of a still smaller individual. Original 



'D J 



1 Beitr. vorwelt. Fauna d. Steinkohlengebirgcs, p. 3 (1847). 

 - Ibid p. 6. 3 Ibid. p. 7. 



