coe: nemerteans of west and northwest coasts. 23^ 



of a deep green color, and these impart the characteristic coloring 

 to this portion of the body. The pigment is in this instance quite 

 insoluble in alcohol, ether, xylol, cedar oil, or any of the commonly 

 employed clearing reagents. 



In many forms very numerous highly refi-active globules, appar- 

 ently similar to fat or oil drops, are encountered, and other vacuoles 

 of fluid suggest food materials being stored up or in process of 

 assimilation. Other cells contain various concretions and sometimes 

 crystals. The body of the cell is so crowded with these apparently 

 non-living substances that there seems to be but little space for the 



YiG. 6.— ParonemeHes calif ornica. Transverse section of body a short distance 

 behind brain, showing stomacli (e), proboscis sheath {re), and the two distinct 

 layers of longitudinal muscles (Im and hn') of body walls separated by a thick 

 layer of parenchyma {por). 



cytoplasm. The nucleiis is usually extremely minute and is situated 

 near the base of the cell. 



The rectum is similar to the intestine proper in histological struc- 

 ture. 



The lining of the mouth, esophagus and stomach is, so far as is 

 known, always dei-ived from the ectoderm of the embryo, while the 

 epithelium of the intestine proper and rectum is entodermic in origin. 



B. Hoplonemertea. — In this order the mouth is compara- 

 tively small and usually closely connected with the rhynchodaeum, 

 although in Drepanopiiorus it is situated a little behind the open- 



