COE: NEMERTEANS OF WEST AND NORTHWEST COASTS. 247 



Proboscis very long and large, of a pale, slightly jjinkish color. 

 Central stylet slender and acutely pointed, having a very slender 

 basis of about the same length as stylet (Text-fig. 12). Basis 

 peculiar in that it is no wider, and is often narrower posteriorly 

 than at attachment of stylet. It is often irregular in shape (Text- 

 fig. 52) and about five or six times as long as its average width. 

 Measurements vary from 0.07 to 0.1 mm. in length and O.Olo to 

 0.017 in ^^ddth. Two pouches of accessory stylets contain from 

 two to four slender stylets each. Proboscis sheath reaches very 

 nearly to posterior end of body. Retractor muscle of proboscis 

 composed of about six strong fibers, attached in two groups to wall 

 of sheath. 



Blood system, as in related species. In every individual of a large 

 number of specimens the dorsal, or proboscis sheath vessel origi- 

 nated anteriorly from the right lateral vessel (Text-fig. 20) . 



58. Amphiporus imparispinosus Griflin. 

 Ann. New York Acad. Sci., 11, p. 210, 1898. 



Amphiporus leuciodus Coe, Proc. Wash. Acad., 3, p. 51, PI. 7, fig. 



6, 1901 ; Harriman Alaska Expedition, 11, p. 51, 1904. 

 Amphiporus leuciodus Punnett, Proc. Zool. Soc. London, p. 95, 



1901. 



PI. 16, figs. 99, 100; PI. 25, figs. 195-197 ; Text-fig. 53. 



This abundant and widely distributed species may be recognized 

 by the following characters : — Body small, usually 25 to 50 mm. in 

 length, remarkably slender, slightly flattened posteriorly. 



Color opaque white, sometimes with a pale reddish or yellowish 

 tinge, sometimes pale yellow, or flesh-color ; brain is pinkish ; intes- 

 tinal canal often has brownish tinge. 



Ocelli. — There are two groups of ocelli on each side of liead ; an 

 elongated, anterior, marginal group of 6 to 15 ocelli, and an irregu- 

 lar, posterior group of about the same number, or, rarely, up to 30 

 or more lying internal and posterior to marginal groups and imme- 

 diately anterior to brain (PI. 16, fig. 99; PI. 25, figs. 195-197; 

 Text-fig. 53). Smaller and evidently younger individuals have 

 much fewer ocelli. 



