SYNELMIS SIMPLEX. 177 



Parapodia biramous, with notopodial as well as neuropodial aciculum 

 strongly developed, and the notopodium proper but weakly elevated. Neuro- 

 cirri as well as notocirri well developed throughout; swollen proximally and 

 abruptly narrowed distad, smooth and undivided. 



A single seta in each notopodiiun, this simple and very stout. Neuropodial 

 setae numerous and all simple. 



Genotype. — S. simplex, sp. nov. 



This genus stands apart in the character of its eyes, in the absence of com- 

 posite setae throughout, and in the distinct notopodial development with an 

 aciculum, as indicated for the pecuhar genus AncistrosyUis of Mcintosh. In 

 the subgenus Haplosyllis of Sylhs the setae are similarly all simple though of a 

 type quite different from those characterizing Synelmis. In the shortness and 

 simplicity of the tentacles it is hke Rhopalosylhs described by Augener from 

 Australia (Fauna Siidw.-Austr., Polych., 1, 1913, 4, p. 245), though these in the 

 latter appear very different from the presence of the numerous papillae. The 

 form of the cirri suggests that characterizing the species of Sphaerosyllis. The 

 general relations of the genus are sufficiently shown in the key (p. 16-1). 



Synelmis simplex, sp. nov. 

 Plate 28, fig. 1-5. 



Body in general yellow, in parts brownish or somewhat reddish brown. 

 Setae and acicula all colorless. 



Body elongate and slender, almost thread-like. Essentially uniform in 

 width excepting at the caudal end, where it narrows to a point, and at the extreme 

 anterior end, where it widens somewhat clavately. The number of somites 

 in a type-specimen is one hundred and sixty-three. The length is 56 mm. and 

 the greatest width, exclusive of the parapodia, 1.2 mm. 



The prostomium projects from the dorsal side of the anterior surface of the 

 broad, anteriorly tnincate peristomium as a short piece widely convex in front 

 or nearly rounded, triangular and rapidly shorter laterad. It bears two stout, 

 two-jointed palps, wliich are but slightly separated at base and project almost 

 directly forwards. The terminal article in each palpus is much shorter and nar- 

 rower than the other, and is rounded. There are three tentacles, all shorter 

 than the palps and slenderly conical, constricted at level of attachment, and 

 colorless and translucent. The median tentacle is attached on the median 



