(•.\i,iI''()i;ma KriuMi.in.K. 



than the cirriilar museiiliir layer, and this again is thinner than tlie longitndinal 

 mnsonlar layer. The clitelhim is perfect, bnt somewhat thicker on (he npper part. 

 The glandular layer is very thirk, lieing about ten times thicker than the two nnis- 

 cular layers combint'd. The longitndinal fibres are nowhere arranged in such 

 I'eatlier-like bunches as in Lumbricus, liul niiicli more irregidar, with a faint ten- 

 dency to feathcr-likc bunching. This is th(> rule both in the clitelluni and elsewhere. 

 This stratum of haigiludinal Hbres i.s, as usual, interrupted in four places by the setal 

 grooves, though there are also fibres between the seta'. In the center, between 

 these grooves, the layer is thickest, frdui lluic gradually tapering towards the setic. 

 The under side, or the ventral part, of tiie layer is soujewliat thicker tiian tiic dorsal 

 part. 



The clitellar glands are less regularly paired than in Ijumbricus (hough 

 the general arrangement is that of two or three rows of glandular cells together. The 

 clitellum is veiy thick and developed all around the body. 



Alimentary canal (fig. 1). The buccal cavity is eversible to a remarkable de- 

 gree, so much so that it is often projected like a large sac or bladder, covering hiore 

 or less perfectly the ]irostomium and part of the peristomium. Its walls are very 

 thin and transparent. The pharynx commences with the prostomium and covers 

 somites i, ii, iii, but is only dorsally developed. It is much and irregularly folded, the 

 sinuses being sac-like and not parallel, the largest ones being in somites ii and iii. 

 The muscles of the pharnyx are thickly covered with salivary glands. Ru[)eriorly 

 these glands project along the under side of the muscular bands, which extend back- 

 ward, thus forming three rows of parallel projections tapering from base to apex. The 

 anterior of these salivary glandular masses is the largest, the third, or the most posterior 

 one, the shortest (figO). The jjosterior half of the salivary glandular mass forms one 

 single projection equal to all the anterior ones together. This gland is connected with 

 and partially rests on two muscular bands attached to the body-wall between somites 

 vii and viii. 



GSsnphayus commences between iii and iv, extending backward to somite xvi, 

 being slightly differentiated in xiv, xv, and part of xvi, as a tubular intestine (fig. 1). 

 ffisophagus is much sacculated, first rising upward and forming a sigmoid jdexus in 

 somite vii, after which it lowers itself somewhat in viii and then extends gradually 

 backward to the sacculated intestine, at the same time gradually diminishing in size. 

 The tubular pait in xv or between xv and xvi is the narrowest part of the oesophagus. 

 The glandular ejiithelium of the (jesophagus is very narrow in the anterior somites, or 

 those in front of the clitellum, and the blood sinuses in them are narrow. In the 

 anterior part of the clitelluni the epithelial villi become greatly elongated with in- 

 creased blood sup])ly, while in the central part of the clitellum these blood sinuses be- 

 come very large, occujiying the largest part of the epithelial lobes. The nuclei in those 

 epethelial cells are everywhere round. 



The sa cat 1(1 ted infedini', fig. 1, .s. i., commences in xvi, is generally al)out four or 

 lU'v times wider than the tubular intestine. It does not increase gradually, but at 



