No. (Mf>] 



77//-; 7/J/i? OF MAMMALS 



515 



creasing acuminateness, while Figs. 18 to 20 show curious 

 anomalous varieties. 



In Figs. 1S1 and 182 are shown two isolated acuminate 

 scales of characteristic outline. 



The elongate type of cuticular scale (Figs. 21 to 35) 

 is one least often met with, especially in its typical form, 

 as shown in Figs. 29 to 31. The simplest variety (Fig. 

 21) possesses a longitudinal axis only a trifle greater 

 than the transverse one. Figs. 29 to 31 are the typical 

 varieties, and Figs. 32 to 35 show forms difficult to group. 

 They are, however, tentatively put with the elongate 

 forms. A single dissociated elongated scale is shown in 

 Fig. 183. 



By far the commonest types of scale which one encoun- 

 ters are the eremite ami flattened types. The former are 

 illustrated by Figs. 36 to (57. In this form of scale the 

 transverse axis is much greater than the longitudinal, 

 and the free ectal, or outermost edge of the scale is ir- 

 regularly waved or crenulated. < )f this type, a confusing 

 multiplicity of variations occur. Some of the plainest 

 and most easily interpreted of these are shown. Fig. 36» 

 is considered to represent the simplest form. Scales 

 like those shown in Figs. 57 to 67 are usually associated 

 with the hairs of the greatest diameter, i.e., the coarse, 

 or stiff hairs, or bristles. This form is also character- 

 istic of the majority of the spines. Two typical crenate 

 scales, dissociated from the cortex, are represented by 

 Figs. 185 and 186. 



The flattened type is equally common and differs from 

 the crenate only in exhibiting an ectal edge smooth and 

 comparatively free from sudden irregularities. The 

 longitudinal axis, however, is frequently but little greater 

 than the transverse one, as can be seen in such hairs as 

 are represented by Figs. 69 and 70. Pig. 6S represents 

 the simplest form, and Fig. 184 a single scale of the same 



