WAGENER^ ON GYRODACTYLUS ELEGANS. 201 



attached to it two strongs striated^ fibrous bundles, which 

 proceeding towards the centre of the disc are there lost. 

 How this appendage is connected with the wing is not ap- 

 parent. If we suppose the peduncle to be protruded, and 

 the appendage drawn backwards, the point of the hook, which 

 is somewhat moveable upon botb, is elevated; whilst if the 

 stem be retracted, the hook is withdrawn. 

 ;- The transverse oral fissure, which is placed on the ventral 

 side of the animal, close to the roots of the cephalic lobes, 

 leads to the digestive apparatus. 



The oral opening forms the lower termination of the 

 shallow groove between the cephalic points, and leads into a 

 short pyriform sac, with very thin walls, in which a longitu- 

 dinal striation may sometimes be perceived. 



Attached to the bottom of this sac, exactly as in Diplozoon 

 or Diporpa, lies a protrusile pharyngeal organ, which, if the 

 examination be awkwardly conducted, may even be forced 

 altogether out of the oral orifice. This turban-shaped 

 pharynx consists of two parts. 



The upper, which projects free into the oral cavity, has 

 eight points, which, as remarked by Von Siebold, can be 

 moved against each other, like jaws. The conical summits 

 of these eight divisions of the pharyngeal organ is finely 

 striated longitudinally. The small jerking movements which 

 take place in these parts give them the aspect of hard 

 bodies. But when they are protruded beyond the mouth, 

 they expand into an eight-rayed star ; the fine longitudinal 

 striae disappear, and they rather resemble a structureless, 

 tough substance. 



The lower portion of the pharynx, upon which the eight 

 cones are seated, is of a flattened spheroidal form. It is 

 composed of eight cell-like segments, separated from each 

 other by as many meridional grooves. Upon each is placed 

 a pointed process, which is also separated from it by a 

 groove. These transverse grooves, forming a circle around 

 the pharynx, divide it into a superior and an inferior 

 portion. The eight cellseform bodies have fine granular con- 

 tents, in the centre of which may be "perceived a very clear 

 spherical cavity filled with fluid, and containing a globular 

 opaque nucleolus. 



The pharynx of many Distomata is formed in a similar 

 manner, except as regards the conical processes. Within 

 the longitudinal and transverse strise, which are usually re- 

 garded as belonging to a muscular structure, may also be 

 noticed transparent, nuclear, sharply defined spaces, inclosing 

 each a nucleolar corpuscle. 



