COE: NEMERTEANS OF WEST AND NORTHWEST COASTS. 145 



habits, and internal anatomy, and indicates these peculiarities by- 

 two varietal names. Careful study of his preparations, however, 

 and a comparison with specimens collected in California, show such 

 a close intergradation that it seems certain that all the forms of the 

 genus thus far collected on the Pacific coast belong to a single 

 variable species. The apparent amount of gelatinous tissue, or 

 parenchyma, is largely dependent on the state of contraction of the 

 parts. 



After preservation the natural colors are completely lost; the 

 body becomes nearly cylindrical and is flattened only towards its 

 posterior extremity ; head is not usually distinctly marked off from 

 body, and in only a few specimens is it broadened as in life. 



In internal organization the species agrees closely with the descrip- 

 tions and figures which Burger has ])ublished for G. armancU ('95) 

 and C. patagonica ('96). Bergendal has recently (:02, :03, and 

 : 04) furnished additional observations on G. armandi. In many 

 details, however, the present species presents such interesting ana- 

 tomical pecuUarities that a rather extended description of the inter- 

 nal anatomy seems to be warranted. 



Integutnent and body icalls. — 1. The outer integument, Avith its 

 superficial layer of columnar ciliated cells and deeper layers of gland 

 cells, is much as in G. armandi. About the middle zone of this 

 epithelial layer we meet an irregular network of slender fibers, cor- 

 responding to the muscular layers described by Burger ('95) . Ber- 

 gendal (: 02, p. 14) has also described these epithelial muscles in 

 detail. In the species at hand, both circular and longitudinal layers 

 are readily distinguished. 



2. The basement layer (PI. 12, fig. 79 ; PI. 13, figs. 81, 82) of 

 fine connective tissue fibrils and gelatinous tissue is far more highly 

 developed than in any of the other species of the genus. In the 

 esophageal region it is about equal in thickness to the integument 

 itself, but decreases greatly farther back. 



3. Beneath the thick basement layer, and not sharply demar- 

 cated from it, is a comparatively loose sheet of circular muscular 

 fibers (PI. 12, fig. 79). These fibers are more slender and scattered 

 than those of the other muscles of the body, and are intimately con- 

 nected Avith the surrounding connective tissue. The layer varies 

 greatly in thickness in different portions of the body, but is never 

 very strong. It extends throughout the length of the body. 



