66 Hobert E. Coker. 



they shade off into furrows, the furrow is mesial, and the seam most ' 

 distinct at the periphery. Further, in Malaclemniys, as has already 

 been shown ('05a, p. 14 ff.), the successive concentric rings of 

 growth give a sure means of determining that the incomplete seams 

 noted in that species are of subsequent development. This seems 

 sufficient to make "partial division" acceptable. It may be added that 

 the incomplete seams would be quite inexplicable on the supposition 

 of fusion. Gadow's hypothesis may presuppose fusion of scutes, but 

 these cases could not fall in line with his hypothesis.^ We would 

 have scutes fusing that were not supposed by the hypothesis to fuse 

 (cf. Figs. 81, 82, 91). On the other hand, as expressions of laws 

 of growth that are not complied with until these seams appear, the 

 late appearance of the seams is quite explicable. It is evident that, 

 instead of suggesting arrest of development as the explanation of 

 supernumerary scutes, they would point in a contrary direction. 

 If they have a significance as to ontogenetic development they point 

 to perfection of adjustment as opposed to perfection of number of 

 elements. See also Fig. 101 (specimen 210, not listed). 



Finally, whether the blind seams represent division in process, as 

 suggested, or merely broken seams in stable condition, their positions 

 and their peculiar association with other abnormalities are too sug- 

 gestive to go unremarked. 



We speak of supernumerary scutes, although it may be more a 



matter of seams than of scutes. We have to do merely with the 



subdivision by seams of a given horny area. What determines the 



plan of the seams, to what extent it is dependent on vasculation or on 



the relations to the bones and other organs beneath, we do not know, 



but it is quite conceivable that the laws of growth and of adaptation 



to diverse environmental conditions are adequate to account for the 



diverse plans of scutes. The evidence points very directly to the 



conclusion that the development of asymmetrical seams in the neural 



region takes place in accord with laws of growth as distinguished 



from laws of heredity, and this may well be the case with other 



abnormalities. 



'Gadow's figures are not reviewed liere, since, though showing a high degree 

 of multiplication of scutes in the several series, the supernumerary scutes are 

 hardly comparable to those dealt with in this section ; supernumerary scutes 



