COE: NEMEETEANS OF WEST AND NOETHWEST COASTS. 9 



One type of these gland cells stains most deeply with nuclear 

 stains, the cell is flask-shaped and is filled with a more or less 

 coarsely granular or foamy secretion (Text-fig. 1, «, a'), while the 

 other type (Text-fig. 1, c, c') stains chiefly with plasma stains, the 

 cell is rod-like in shape and contains a homogeneous, viscid secre- 

 tion, which is often found pressed out of the cell body and lying 

 among the cilia on the surface of the integument. A third type of 

 gland, found in many species, consists of clustered gland cells which 

 pour their viscid secretion out through a common passage among 

 the more superficial cells. This type of gland cell may lie deep in 

 the integument, as in Carinella, or may sink beneath the base- 

 ment layer to lie among the muscular fibers of the body walls, as 

 in Taeniosoma and the Lineidae. Or, similar glands may sink into 

 or even entirely through the muscular layers of the body w^alls to 

 form the sub-muscular glands of the Hoplonemertea (Text-fig. 3). 

 The glands of this type commonly show a marked affinity for 

 nuclear stains, and their secretions are in many cases distinctly col- 

 ored in the living worm, thereby affecting the natural coloration of 

 the body. 



The arrangement of the ciliated and glandular cells, as well as the 

 thickness of the integument, is decidedly varied in the different 

 orders. For details of these peculiarities, compare Burger's Mono- 

 graph ('95), p. 204-216. 



Among the bases of the glandular and epithelial cells are numer- 

 ous interstitial cells, some of which are of the nature of connective 

 tissue elements, while others are strictly epithelial (Text-fig. 1, d, e). 

 These interstitial cells are commonly profusely branched and serve 

 to bind the other integumental cells together. 



In the species of Zygoxemertes characteristic sickle-shaped or rod- 

 like masses of homogeneous, hardened secretion of pale yellow color 

 are situated among the outer borders of the epithelial cells, while 

 somewhat similar bodies are found in Amphiporus biniaculattis and 

 A. impai'ispinosus. They are e"specially conspicuous in Emplecto- 

 nerna echi)iodermum of Europe, and in all cases appear to originate 

 as secretions in glandular cells of the integument. 



Specialized sensory cells of very slender form and provided with 

 a single flagellum occur at fi-equent intervals among the ciliated and 

 glandular cells (Text-fig. 1, /")• 



Other sensory cells are scattered throughout the integument, and 



