226 PROCEEDINGS OF THE ACADEMY OF [April, 



The prostomium and somite II are apodoiis, short simple rings. 

 All others bear parapodia, but are not otherwise more complicated in 

 structure. Up to about the fifteenth they increase in size, but remain 

 uniannular throughout. The body is strongly arched above and 

 nearly flat below, and terminates in a simple ring-like pygidium bear- 

 ing a pair of small ventral anal cirri as long as the diameter of the 

 pygidium. 



Parapodia'are small, slender and strictly lateral in position. Except 

 that they correspond in size with the segment bearing them and are 

 consequently largest at the middle of the body, they are quite similar 

 throughout. The neuropodium (fig. 13) is slender, nearly cylindrical 

 and slightly enlarged distally, where it terminates in a presetal lobe 

 divided into a larger ventral and a minute acicular process, and a 

 postsetal lobe which begins just below the aciculum and runs to a 

 rather prominent dorsal angle. Its dorsal surface bears a group of 

 long cilia. The neuropodial cirrus is a simple finger-like papilla arising 

 in or near the distal third of the ventro-posterior siu"face of the 

 neuropodium and reaching nearly to the end of the latter. 



The dorsal cirrus arises immediately above the base of the neuro- 

 podium and consists of a slender, elongated cirrophore nearly as long 

 as the latter and slightly diverging from it. Usually but not always 

 it is slightly constricted about the middle and the end is a little thick- 

 ened. Probably it represents the notopodium, as what appears to be 

 a slender aciculus penetrates about half of its length. A tuft of long 

 cilia resembling that on the dorsal surface of the neuropodium is 

 usually present on its ventral and sometimes on its dorsal surface also. 

 On the end of this basal piece is borne a terminal style of about half 

 its length and of a slender, conical form. The first parapodium 

 altogether lacks a dorsal cirrus. 



Setse are numerous and of four forms, all very delicate, transparent 

 and colorless. They are arranged in well differentiated supra- and 

 subacicular fascicles, each comprising two kinds, and'all of which occur 

 throughout the body, except perhaps in a few anterior segments, where 

 the long compound setse have not been found. 



All of the supraacicular setae are simple ; those most numerous being 

 very delicate but stiff capillary bristles, tapered to very acute tips, 

 slightly curved and rather strongly serrated in an antrorse manner 

 along one side (fig. 20). Their exposed parts are fully three times as 

 long as the entire neuropodium. The other form has generally stouter 

 stems, straight and tapering until near the end (fig. 19), where they 

 present a gentle ventral curvature and at the same time become 



