162 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



provided with numerous minute ocelli, often arranged in a single 

 row on each side of the head. A caudal papilla or cirrus, a diagonal 

 muscular layer, and neurochord cells are all wanting. The pro- 

 boscis sheath is often short in comparison with the length of the 

 body. 



This genus is represented in the region covered by this report by 

 at least seven species, of which but one (X. viridis) has been 

 found in other parts of the world. 



15. Lineus viridis (Fabr.) Johnston. 



Planaria viridis Fabricius, in O. F. Miiller, Zool. Dan. Prod., 



1776; Fauna Groenlandica, p. 324, 1780. 

 Planaria gesserensis Miiller, Zool. Danica, 2, p. 32, 1788. 

 N'emertes ohscura Desor, Boston Journ. Nat. Hist., 6, pp. 1 to 12, 



1848. 

 Lineus viridis Johnston, Catalogue British Non-parasitical Worms, 



pp. 27, 296, London, 1865. 

 Lineus viridis Coe, Proc. Washington Acad. Sci., 3, p. 65, 1901 ; 



Harriman Alaska Expedition, 11, p. 65, 1904. 



Body moderately slender, rounded throughout, but slightly flat- 

 tened posteriorly ; head slightly wider than the parts immediately 

 following ; cephalic slits long and deep, with pale margins above and 

 below, reaching anteriorly close to the proboscis pore. The anterior 

 end of the mouth does not reach quite so far forward as the pos- 

 terior end of the cephalic slits. Length usually 100 to 200 mm. 



On each side of the head in front of the brain and close to the 

 lateral borders is a single row of minute ocelli. The number of 

 these is commonly from four to six on each side, though some 

 individuals have as many as eight, and very young specimens but a 

 single pair. 



Color. — The x\laska specimens were dusky or brownish green, 

 becoming dark brown anteriorly, and commonly paler on the ven- 

 tral surface, especially posteriorly. The species is extremely vari- 

 able in color, and in other parts of the world green, olive colored, 

 brown, red, and smoky black varieties have been described. The 

 head is very pale on lateral margins and in front. The brain is 

 large, reddish, and shows distinctly through the pigment of the 



