ALASKA NEMERTEANS 23 



tending into the cavity of the blood space nearly so far as in the former, 

 but are much more profusely branched than in the latter species. The 

 single pair of efferent ducts lies in the same region as the posterior 

 ends of the series of ' nephridial glands.' Posteriorly to this point a 

 single unbranched duct of large size runs backward on each side for 

 a considerable distance, and then bends sharply and runs forward to 

 the efferent duct, always lying close beside, and just external to that 

 limb of the duct which is passing backward. The efferent ducts open 

 on the dorso-lateral surfaces of the body at the posterior end of the 

 enormously thickened internal circular muscular layer. 



The blood vascular system, brain, buccal nerves, lateral nerves, and 

 dorsal and ventral median nerves are much as in C patagonica. 



Specimens collected in August had just discharged their sexual 

 products. In one individual a very few genital sacks still retained 

 their mature ova. 



EMPLECTONEMA Stimpson. 



Emplectonetna Stimpson, Proc. Philadelphia Acad., p. 163, 1857. 

 Nemertes McIntosh, British Annelids, Part I, Nemerteans, Ray Society, 



1872-1873. 

 Eunemertes Vaillant, Hist. Nat. des Anneles, Tome 3, Paris, 1890. 



Body very long and slender, varying greatly in thickness according 

 to state of contraction, but most commonly considerably flattened ; 

 often sharply bent and folded into an irregular mass ; integument pro- 

 vided with an unusual abundance of mucous secretion ; proboscis and 

 mouth opening together on subterminal portion of snout ; proboscis 

 sheath limited to anterior third of body ; proboscis slender and very 

 short, often not more than yi the length of body ; a large number of 

 minute eyes usually present ; cerebral sense organs situated well in front 

 of brain, and usually very small. The species are of sluggish move- 

 ment, and many of them are found very near high water mark among 

 mussels, barnacles, rockweeds, etc. 



Of the genus Emplectonema two species, of which only one (^E. gra- 

 cile) had previously been described, were found on the Harriman ex- 

 pedition. 



6. EMPLECTONEMA GRACILE (Johnston) Verrill. 



p1. viii, fig. 3. 



Nemertes gracilis ]on^S'Y:oii, Mag. Zool. and Bot. London, vol. i, 1837-38. 

 Emplectofiema viride Sti^fso'S, Proc. Philadelphia Acad., p. 163, 1857. 

 Eunemertes gracilis Vaillant, Hist. Nat. des Anneles, Tome 3. Paris, 1890. 

 Eunemertes gracilis Burger, Fauna u. Flora des Golfes von Neapel, 



Monogr. 22, Nemertinen, p. 543, 1895. 

 Emplectonema gracilis W^KKl'LL,, Trans. Connecticut Acad., vili, p. 413, 1892; 



ix, p. 146, 1895. 



