PHARYNGEAL GLAND OF THE EARTHWORM 57 
belong to the intestinal epithelium but are amoebocytes of the 
haematic system which fulfil an excretory function. 
(c) Reserve substance vn Oligochaetes. 
From the work of Gegenbaur, Beddard, and Cuénot it is known 
that the usual nutrient reserve substance of Oligochaetes is 
glycogen, which is localized in the special peritoneal cells which 
surround the nephridia. These authors have also mentioned 
that in some earthworms the glycogen is replaced by fat. 
TEXT-FIG. 7. 
Coelomic cells containing droplets of fat (cf. Text-fig. 1, f.c., p. 40 
of this paper). x 1,100. 
More recently Willem and Minne (1899 a), who have made 
complete analyses of earthworms, found that their reserve 
substance is composed of fat and glycogen, the first being 
localized in the ciliated cells of the intestinal epithelium, 
while the second is found in the peritoneal cells.* 
1 The following is a quotation from the paper of these authors: ‘On 
rencontre chez les lombrics, comme produits de réserve, de la graisse et du 
glycogéne ; la premiére, constituée surtout par de Voléine, est localisée 
dans des cellules ciliées de épithélium intestinal ; le glycogene s’observe 
dans des cellules péritonéales et fournit, comme dérivé, de la dextrine ° 
(pp. 42-3). 
