600 BRITISU ORIBATID^. 



side of the back part of the labium, and its hinder edge 

 practically curves round the lower portion of the en- 

 trance to the pharynx, into which it doubtless conveys 

 the food. It is usually triangular or spoon-shaped, 

 when taken as a single organ, and is strongly concave 

 upward in transverse section. In some species the 

 transverse bands of muscle which characterise the 

 oesophagus are continued on the hind portion of the 

 lingua. 



The lingua really consists of two paired halves ; it 

 is not a single azygous organ, although the two 

 halves generally meet at their inner edges and have 

 that appearance. In prepared specimens the two 

 halves generally separate, and become quite distinct 

 from one another ; each half then forms a more or less 

 right-angled triangle, the straight sides being inward. 

 In many species, e. g. Cepheus latus, each half of the 

 lingua terminates anteriorly in two strong setae or 

 hooks (PL LIII, fig. 7), which curve upward, and it 

 may be otherwise provided with hairs. The lingua is 

 shown in PI. LIII, figs. 5 and 6. 



The Epipharynx is also a delicate, membranous, 

 triangular or spoon-shaped organ ; but it arises from 

 around the upper edge of the pharynx, and stands 

 straight outward into the mouth-cavity ; where it forms 

 a sort of hood overhanging the entrance to the 

 pharynx ; it is concave downward in transverse section, 

 and appears not unlike the lingua turned upside down, 

 although the two are not really of the same shape in any 

 species that I have dissected. The epipharynx, in all 

 instances known to me, is a single azygous piece, not 

 two paired halves ; and I have not seen it terminated 

 by any setse or hooks. It can usually only be seen in 

 dissections ; it is shown in PI. LIII, figs. 5, 6, 8. 



