ALASKA NEMERTEANS 



65 



23. LINEUS VIRIDIS (Fabr.) Johnston. 



Plafiaria viridis 0. Fabricius in 0. F. Miiller, Zool. Dan. Prod., 1776 ; Fauna 



Groenlandica, p. 324, 1780. 

 Planaria gesserensis Muller, Zool. Danica, u, p. 32, 1788. 

 Ntmertes obscura Desor, Boston Journ. Nat. Hist., vi, pp. 1 to 12, 1848. 

 Linens viridis Johnston, Catalogue British Non-parasitical Worms, pp. 27, 



296, London, 1865. 



As stated by Verrill, 1 there seems little doubt that the description of 

 this species sent by Fabricius to Muller and published by him in the 

 Zoologica Danica, is entitled to retain priority in nomenclature instead 

 of Muller's gesserensis of later date, which has been adopted by most 

 recent European writers. 



Characteristic individuals of this species were found under stones at 

 low water at New Metlakahtla, on Annette Island. 



Body moderately slender, rounded throughout, but slightly flattened 

 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 posterior 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 (fig. 16). 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 Alaska specimens were dusky or brown- 

 ish green, becoming dark brown anteriorly, and com- 

 monly paler on the ventral surface, especially posteriorly. 

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

 The brain is large, reddish, and shows distinctly 

 through the pigment of the body. Cerebral sense or- 

 gans paler but easily distinguished in life, with con- portion of body 

 spicuous canals leading to the posterior ends of the of Lineus viri- 

 cephalic slits (fig. 16). dis showing ar- 



Habitat. This species, besides being found in Alas- H. men , 



ocelli, and posi- 

 ka, is widely distributed in northern waters. On the tion of brain ce _ 



east coast of America it occurs from Long Island Sound phalic sense or- 

 to Greenland. It is found on nearly all the coasts of gans and mouth, 

 northern Europe. It has also been found in the Medi- X . 

 J Trans. Connecticut Acad., viii, p. 421, 1892. 

 Wash. Acad. Sci., March, 1901. 



Fig. 16. Out- 

 line of anterior 



roc. 



