Metazoa L umbricus. 



237 



of the oesophagus are three (or in some worms two) pairs of 

 glands, known as calciferous glands. These glands contain 

 crystals or granules of carbonate of lime. They appear to 

 communicate with the oesophagus, but their function has not 

 as yet been determined. The crop is, like the pharynx, an 

 extensible muscular organ, and in it the food matter is no 

 doubt stored before it passes into the drum-shaped gizzard, 

 whose powerful muscular walls and thick horny lining crush 



FIG. 121. LONGITUDINAL SECTION THROUGH THE ANTERIOR PORTION [OF 

 Lumbricus terrestris. (Hurst.) 



BC, buccal cavity ; c, crop ; cu, cuticle ; D, thickened cuticle of the gizzard ; 

 E, epithelium of the alimentary canal ; EP, epidermis ; G, gizzard ; IN, in- 

 testine ; M, retractor muscles of the anterior part of the oesophagus ; MC, 

 circular muscles of the body-wall ; MG, muscular wall of the gizzard ; ML, 

 longitudinal muscles of the body-wall ; MV, posterior median vesieula semi- 

 naiis ; N, dorsal portion of the nerve collar cut across ; NC, ventral nerve- 

 chain ; NP, nephndium : OD, oviduct ; OE, oesophagus ; OG, aperture of cal- 

 ciferous gland ,'ov, ovary ; PH, pharynx ; P.M, retractor muscles of pharynx ; 

 PS, prostomium ; SF, mouth of vas deferens ; T, anterior testis ; TY, typhlo- 

 sole ; VD, vas deferens. 



any foodstuffs that require mastication or grinding. The 

 posterior portion (third) of the gizzard has thinner walls, 

 and leads into the long glandular and sacculated intestine. 

 Down the dorsal surface of the intestine, and hanging free in 

 its interior, runs a curious fold, the typhlosole, a structure 

 which is found in a large number of animals. It no doubt 

 serves to greatly increase the area over which absorption of 

 the food takes place, for it is in the intestine that that pro- 

 cess especially goes on. The numerous folds and saccula- 



