398 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
acicular fascicle, from 13 to 20 setae in each. Anal cirri wanting 
in all the specimens. 
Length of largest specimen, 25 mm.; width, 3.8 mm. 
A few specimens from Alki Point, collected by Miss Robertson, 
Aug. 3, 1898. None are perfect, the tentacular and dorsal cirri, in 
particular, being very caducous. The species occurs also at Pacific 
.Grove. 
Nereidae. 
13. Nereis virens M. Sars. PI. 3, figs. 26-30. 
Nereis virens Grube. Middendorff’s Reise in den aussersten nor- 
-den und osten Siberiens, bd. 2, Zool., th. 1, 1851, p. 6. Taf. 1, figs. 
2 - 6 . 
Alitta hrandti Malmgren. Ofversigt af k. vet. akad. forhand- 
lingar, Stockholm, 1865, p. 183. 
N. foliata Baird. Appendix to John Iveast Lord’s “Naturalist 
in Vancouver Island and British Columbia,” vol. 2, 1866, p. 347. 
N hrandti Elders. Die borstenwtirmer, 1868, p. 563. 
I cannot agree with Elders (’68) and Malmgren (’65) that this 
North Pacific Nereid is distinct from N virens of the coasts of 
Northeast America and of Northern Europe. I have compared 
specimens from the two oceans, and fail to find any differences that 
can be considered of specific value. It is apparently an interesting 
instance of discontinuous distribution, since the species seems not 
to attain high northern latitudes. The coast of Norway, the 
Gulf of St. Lawrence, and the Sea of Ochotsk (Grube) are the 
northern limits of its known distribution. It is likely to be found, 
however, on the more southern shores of Alaska. I have not found 
it on the California coast further south than Bolinas, about ten miles 
north of San Francisco. 
The species attains a much greater size in the Pacific than in the 
Atlantic. Whereas an Atlantic N virens of a length of 26 cm. in 
the contracted condition would be considered large, a length of 50 
cm. and a diameter of 25 mm. under the same conditions are not 
infrequent dimensions on the western shores of North America 
(Fig. 26). 
The Heteronereis of this species I have not seen, but as usual 
among Nereids, individuals attain sexual maturity in the ordinary 
or “ atokous” form. 
