ANNELIDS FROM THE N.E. PACIFIC. 
239 
The seta-distribution in these two specimens may therefore be 
summarised thus :— 
Region of body 
Anterior. 
Mid. 
Posterior, 
Notopodial bundle. 
Hom. spins. 
(numerous). 
Hom. spins. (few). 
Hom. fales. (few). 
Hom. fales. (1-2). 
Hom. spins. (rare). 
Upper neuropodial | Hom. spins. |Hom. spins. (fewer). Hom. spins. 
bundle. (numerous). 
Het. falcs. Het. fales. Het. fales. 
(few). 
Lower neuropodial Het. spins. (few). Het. spins. (few). 
bundle. 
Het. fales. | Het. fales. (fewer). Het. fales. 
(numerous). | 
Nereis cyclurus appears to have a considerable range along the 
western sea-board of North America, from Southern California 
(Moore, 12) to Puget Sound. 
Izuka has described WV. shishidoi, a closely allied species, from 
the eastern side of Japan. The description is based on the 
solitary specimen which has been obtained there. 
It is difficult to imagine what reasons Izuka can have had for 
separating the Japanese example as a distinct species. His 
description and figures, which are excellent, agree exactly with 
NV. cyclurus. His only comment on the relationship of the 
Japanese specimen to the American ones is that WV. shishidot 
‘comes nearest” to WV. cyclurus. Harrington’s description of the 
paragnaths of the basal ring (V—VITJ) is a httle difficult to under- 
stand, and this may have led Izuka to separate his specimen. 
Comparison, however, of the present specimens shows that the 
paragnaths agree exactly with those of the Japanese worm. 
Harrington, after summarising the differences between JV. cy- 
elurus and NV. fucata Sav., concluded that these two worms, both 
normally commensal with hermit-crabs, were closely related. 
Moore (11, p. 343) suggests the generic separation of cyclurus 
from other nereids on account of the extraordinary peristomium. 
To the present writer it seems that these authorities are both 
right in their way. cyclurus is possibly more nearly related to 
fucata than to any other species, as the form of the parapods, 
sete, arrangement of paragnaths, etc., would seem to indicate. 
The enlarged bilobed noto-ligule in eyclwrus, bearing the noto- 
cirrus below the upper lobe, is little more than an exaggerated 
form of the noto-ligule of fwcata. On the other hand, the 
development of the peristomium in the full-grown cyclurus is so 
extraordinary that it might be regarded as ample ground for the 
establishment of a new genus, were it not for the close resemblances 
in other respects to certain other members of the genus Verets. 
