424 Edward Phelps Allis jr.. 



certain that when, in Ameiurus nebulosus, the extrascapular bone is 

 not found as an independent bone, it is because it has fused with the 

 hind end of the squamosal, thus producing a squamoso-extrascapular 

 bone. There being, in these fishes, no supratemporal canal, the extra- 

 scapular element that alone exists is, as Herrick states [47, p. 222], 

 a lateral extrascapular, equivalent to that portion only of the extra- 

 scapulars of the bony ganoids that, is traversed by the main infra- 

 orbital canal. 



McMurrich [53] did not find a parietal bone in Ameiurus nebu- 

 losus (catus) and he considered it as wanting in this fish. I, on the 

 contrary, have always found, in all my specimens, a small bone that 

 was wholly overlooked by Mc Murrich, and that certainly is a parietal. 

 It lies lateral to the posterior portion of the supraoccipital, posterior 

 or postero-mesial to the squamosal, and forms the lateral portion of 

 the dorso-posterior edge of the skull, that edge being a sharp ridge 

 partly formed by this bone and partly by the supraoccipital. The 

 anterior surface of the mesial arm of the suprascapular, which is a 

 flattened process lying in a vertical plane, rests against the posterior 

 surface of the parietal part of the ridge, the ventral edge of the arm 

 resting partly on the parietal, posterior to the ridge, and partly on 

 the adjoining and underlying epiotic (exoccipitale). The parietal thus 

 here has a position that would fully warrant the name, "dermo-epiotic", 

 given by Bridge [19, p. 609] to a bone that he considered as the 

 parietal in Clarias. This bone of Clarias is not particularly described 

 by Bridge, but that author could not possibly have given the name, 

 dermo-epiotic, to a bone that had the position of the one marked 

 parietal by Pollard in his figures of Clarias \60, pi. 35, fig. 1). This 

 parietal bone of Pollard's figure is, moreover, most certainly the 

 supraoccipital, and as such it was considered by Huxley [48, p. 451], 

 that author showing the parietal of Clarias fused with the squamosal 

 and epiotic to form a single bone. As Bridge refers to a dermo- 

 supraoccipital, in Clarias, in addition to the bones that he considered 

 as parietal and dermo-sphenotic, it would seem as if the bone identi- 

 fied by him as the parietal must have had, in his specimen, a position 

 similar to that of the bone that I find in Ameiurus. But, however this 



