PERIPATUS GUTANENSIS. 151 



On the folds of the skin two kinds of papillce are found : 

 first, the primary papillae, large in size, and differentiated to 

 apical and basal portions ; and secondly, the accessory papillae, 

 smaller in size and undifferentiated. As a rule, the basal 

 portion of the primary papillae slopes very gradually, and 

 has an extensive outline which stretches across the entire 

 fold (PL 14, figs. 1 and 2) . The basal outline of the primary 

 papillae is far more distinct near the mid-dorsal line than it 

 is lower down on the sides where the bases of the papilla) 

 run into one another. On the limbs the basal portion may 

 assume an almost cylindrical form. The apical portion when 

 fully extended is almost invariably cylindrical in shape, and 

 carries a spine on its top. The basal portion is covered by 

 short broad scales, but the apical one by long narrow ones. 

 The accessory papilla) present a considerable amount of 

 variation, according to the position which they occupy. 

 Near the mid-dorsal line they stretch across the entire fold, 

 and, as a rule, only one is found between the primary papilla) 

 (PI, 14, fig. 1) ; but near the appendages they are small, and 

 do not cover the fold from side to side, for several of them 

 occupy the space between the primary papilla) (PL 14, fig. 2). 

 It seems that the accessory papillae situated on the sides 

 have been produced by the breaking up of larger ones, 

 similar to those found in the vicinity of the mid-dorsal line. 



The Mouth. — The mouth has the usual shape and posi- 

 tion, and is surrounded by large papilhc which are yellowish 

 white in colour. Half a dozen of these papillae form a 

 horseshoe, situated in front of the mouth, the remainder 

 being disposed in a ring outside. When the mouth is in a 

 contracted condition the complete ring seems to be inside, 

 and the horseshoe outside. The appearance the papilla) 

 surrounding the mouth present depends on the degree of 

 contraction. 



The Genital Aperture. — This opening is situated be- 

 tween the penultimate pair of appendages, and is surrounded 

 by papillce which are slightly enlarged. In some of the 

 specimens the area round the genital aperture is raised, so 



