PVGET SO UND NEMERTEANS. 213 



Length in alcohol, 4-7 cms. Breadth, 5-6 mms. Color 

 (in life) a reddish purple on dorsum, white ventrally. Head 

 with prominent marginal white spots at neck. 



Internal Anatomy. Cephalic gland fairly well developed ; 

 proboscis-pore sub-terminal and anterior to cephalic commis- 

 sure. Cephalic canals enter ventrally and run caudad for some 

 distance in the epithelium. In the region of the mouth they 

 break through the circular muscles to reach the cephalic 

 organs.^ 



Cephalic organs large, considerably in front of brain. Mouth 

 opens into rhynchodeum. Dorsal commissure fairly large. In- 

 testinal caeca short, do not extend near to brain. Anteriorly 

 the integumentary glands are very abundant ventrally, sparsely 

 distributed dorsally. Rhynchoccel surrounded by thin sheath 

 of outer circular and inner longitudinal muscles. In visceral 

 region gonidial pockets are numerous ; a single section shows 

 several, distributed dorsally and laterally to the intestine. 



Habitat and Distribution. Under stones near lowest low 

 water mark. Sitka Harbor and Redout Bay, Alaska. 



Besides A. brunneiLs there are several other forms that bear a 

 more or less general resemblance to A, angttlatus^ and are to be 

 classed among the boreal species. Stimpson's CosmocepJiala 

 BeringianiLS and C. Japoniais are both believed by Verrill ('92) 

 to be varieties oi A. angulatus. At Sitka the present writer ob- 

 tained three quite similar forms (sizes quite different) which seem 

 to approach A. ajiguiatus. When studied under a lens they 

 were seen to possess two paired white lines between which, in 

 two of the forms, the cervical white patches were situated, so 

 characteristic of A. angulatus. In the third these angular 

 patches seem to have been absent or represented by a faint 

 paling of the ground color. Each of the three, with A. angu- 

 latus seemed to characterize a particular zone of the beach be- 

 tween high and low water mark. 



^ The one specimen sectioned showed an interesting abnomiality in the cephalic 

 canal and organ of one side (left?). On this side the cephalic organ lay much 

 further caudad so as to be opposite to the ventral commissure, while its canal forked in 

 the epithelium, one branch opening dorsally, the other more ventrally. The cephalic 

 organ of the right side lay considerably in front of brain. 



Annals N. Y. Acad. Scl, XI, August 13, 1898 — 15. 



