260 bulletin: museum of comparative zoology. 



Glyceridae. 



20. Glycera robusta Ehlers. 



Borstenwiirmer, 1868, p. 656, pi. 24, fig. 31, 32. 



Ehlers based this species upon four specimens forming part of this 

 collection and coming from San Francisco and Mendocino. These 

 types cannot now be found in the collections of the M. C. Z. to which 

 Ehlers states they belong. In the Museum, however, are some finely 

 preserved topotypes from Mendocino (A. Agassiz). Other specimens 

 of the species are simply labeled "California, Capt. Brown." I have 

 found this species not uncommon on Monterey Bay. 



Ariciidae. 



21. Nainereis longa Moore. 



Proc. Acad. nat. sci. Philad., 1909, p. 264. 



Several specimens taken at Crescent City (A. Agassiz). 



22. Nainereis nannobranchia, sp. nov. 



Plate 2, fig. 10; Plate 3, fig. 1. 



This form differs from the others known from the coast of California in 

 having the branchiae begin much farther caudad, the first ones appearing on 

 XX to XXIII, and in the marked reduction of the branchiae in the posterior 

 region. The first ones are small and tubercle-like. The others soon increase 

 caudad to stout conical forms, which curve mesad but with those of opposite 

 sides always well separated by a wide mid-dorsal space, and then, in posterior 

 region, again becoming more slender and much shorter. In structure and 

 arrangement of setae most resembling A'', hespera Chamberlin; but, aside 

 from the very different branchiae, readily distinguishable from that species in 

 the different form of the prostomium, this lacking the anterior median emargi- 

 nation, being simply rounded and as a whole semicircular in outline with 

 anterior end, however, a little narrowed. Postsetal lobe of anterior notopodia 

 larger, subconical, becoming smaller caudad. Postsetal lobe of thoracic 

 neuropodia vertically elongate, but low with edge broadly convex, decreasing 



