ANATOMY AND DEVELOPMENT OF PERIPATUS CAPENSIS. 223 



however, the behaviour of the two blades is very different. 

 The epithelial ridge bearing the outer blade is continued back 

 for a short distance behind the blade, but the cuticle covering 

 it becomes very thin, and it forms a simple epithelial ridge 

 placed parallel to the inner blade. The cuticle covering the 

 epithelial ridge of the inner blade is, on the contrary, prolonged 

 behind the blade itself as a thick rod, which, penetrating back- 

 wards along a deep pocket of the buccal epithelium, behind the 

 main part of the buccal cavity for the whole length of the 

 pharynx, forms a very powerful lever, on which a great part 

 of the muscles connected with the jaws find their insertion. 

 The relations of the epithelial pocket bearing this lever are 

 somewhat peculiar. 



The part of the epithelial ridge bearing the proximal part 

 of this lever is bounded on both its outer and inner aspect by 

 a deep groove. The wall of the outer groove is formed by 

 the epithelial ridge of the outer blade, and that of the inner 

 by a special epithelial ridge at the side of the tongue. Close to 

 the hinder border of the buccal cavity (as shown in PI. XVI, 

 fig. 12, on the right hind side), the outer walls of these two 

 grooves meet over the lever, so as completely to enclose it in 

 an epithelial tube, and almost immediately behind this point 

 the epithelial tube is detached from the oral epithelium, and 

 appears in section as a tube with a chitinous rod in its interior, 

 lying freely in the body cavity (shown in PI. XVI, figs. 13 — 

 16 le). This apparent tube is the section of tlie deep pit 

 already spoken of. It may be traced back even beyond the end 

 of the pharynx, and serves along its whole length for the 

 attachment of muscles. 



The greater part of the buccal cavity is filled with the tongue 

 and jaws just described. It opens dorsally and behind by the 

 mouth into the pharynx, there being no sharp line of demarca- 

 tion between the bnccul cavity and the pharynx. Behind the 

 opening into the pharynx there is a continuation of the buccal 

 cavity shown in transverse section in fig. 13, and in longitudi- 

 nal and horizontal section in fig. 17, into which there opens 

 the common junction of the two salivary glands. This diver- 



