coe: nemerteans of west and northwest coasts. 21 



a2;us vnih greatly convoluted walls, the epithelium of which is several 

 times as thick ventrally as dorsally. The epithelium of the lips is 

 very thick and closely packed with gland cells. In the mouth and 

 esophagus two more or less distinct varieties of glands can be dis- 

 tinguished, due to the different nature of the secretion in each 

 varietv. Both kinds are slender, the nucleus of each cell being 

 placed beneath the cell body in a narrow stalk wliich attaches the 

 cell to the underlying basement membrane. One variety shows a 

 homogeneous, often deeply staining secretion and is more or less 

 rod-like in form. The other variety is characterized by goblet- 

 shaped cells with a much more granular secretion. 



The ciliated cells are superficially placed ; they are likewise goblet- 

 shaped with a slender stalk for attachment, and with the nucleus at 

 the base of the cell-body, but yet not far from the surface of the 

 epithelium, because the ciliated cells are situated above the gland 

 cells. The cilia in this i-egion are short but very numerous. 



In the mouth certain glands often sink beneath the others, or may 

 form a distinct ring about the lips. They form a secretion with 

 peculiar staining proi:)ert'es, which is poured into the buccal cavity ; 

 they are known as salivary or buccal glands. 



In 3ficrnra alaskensis similar glands sink inward beneath the 

 adjacent miisculature and become situated in the outer longitudinal 

 muscular layer, although they nevertheless pour their secretions into 

 the buccal cavity. These have been called accessory buccal glands 

 (Coe, :01, p. 72). 



Stomach. — The stomach is usually decidedly different in its his- 

 tological structure from the esophagus proper, and in Lineus rubes- 

 ce?is, L. flavescens, and other forms, is separated fi'om the latter by 

 a strong muscular constriction, forming a conspicuous sphincter. In 

 Carinoma mutahilis (PI. 12, fig. 76) there is a similar boundary 

 line between esophagus and stomach. In such cases the histological 

 change is very abrupt ; in others it is more gradual. In the stomach ^ 

 a comparatively small proportion of the cells are ciliated ; the cilia 

 are longer but fewer in number, and their nuclei are much fartlier 

 removed fi'om the surface, being situated in the very slender basal 

 stalk which attaches the cell to the underlpng basement membrane. 

 The gland cells are usually packed full of secretion which is com- 



* Compare Miss Thompson's description of Zygeupolia, :02, p. 709. 



