29 



traced outwards tliroiicyli tlio thitdaiess of tlie frop wall. 

 The transverse folds are iufoldinp^s of the side walls 

 between the long-itiidiual folds just mentioned. They 

 oonnect with the single divided longitudinal fold, but 

 not with the pair of longitudinal f(dds. Each of these 

 fohls has secondary foldings on itself, and these run 

 approximately along lines radiating from the centre of 

 thei crop. Xear the inner and free edge of the fold are 

 , smaller papilla-like outgrowths (fig. 18). 



The stomach is lined by (■olnmnar epithelium, with 

 subjacent connective tissue which is not very abundant. 

 The epithelium is fairly even all round except along a 

 line on the internal wall where we find a groove formed 

 by the upgrowth of two ridges. The height of these 

 ridges is due mainly to the unusual height of the 

 epithelium along them, while the cells lining the groove 

 are very short (fig. 20). This description is correct 

 for a young limpet, but as the animal grows older the 

 groove deepens. 



Much of the intestine has ridged walls. The rectum 

 shows two ventro'-lateral folds, wlii(di are covered by 

 fairly high ccdumnar epithelium, growing into its cavity 

 and forming a gutter between them. These folds become 

 much more distinct on the anal papilla (fig. 21), and here 

 they branch into secondary foldings. Fieces seem to be 

 extruded only from the upper sectiou of the rectum, 

 doisal to the " gutter " and folds. 



The buccal glands are made up of much branched tubes 

 which are imbedded in connective tissue, and the ghmds, 

 for this reason, have the aj)pearance of one large mass. 

 The cells lining the gland tubules are large and contain 

 numerous graniiles, they are fairly equal in size and liave 

 large and distinct basal nuclei. The cells near the apices 

 of the tubules appear not to be ciliated, l)ut those furtlier 



