FOLYCHjETOUS annelids from FLORIDA, PORTO RICO. 

 BERMUDA, AND THE BAHAMAS. 



By Aaron L. Treadwell. 



INTRODUCTION. 



In 1911 the present author published a paper entitled "Polychsetous 

 ,\nnelids from the Dry Tortugas, Florida."^ This was the first of a 

 proposed series of systematic papers on the polychsetous annelids of the 

 West Indian region, collected under the auspices of the Department of 

 Marine Biology of the Carnegie Institution of Washington, my main 

 object having been the preparation of a monograph of the West Indian 

 Leodicidffi. It has seemed best, since the final pubUcation must be 

 deferred, to publish a preliminary description of some new species 

 belonging to this family, as well as new species of other families which 

 have been collected incidentally in this work. I have included also a 

 description of a new sabellid belonging to the collection of the American 

 Museum of Natural History. 



FAMILY SYLLID^. 



Odontosyllis octodentata n. sp. 



A relatively large species, approximately 40 mm. long and 2.5 mm. in width. 



The prostomium (plate 1, fig. 1) is broader than long, with the anterior 

 margin broader than the posterior, the lateral angles rounded. The posterior 

 margin has a slight depression which is not shown in the figure because a 

 lobe from the anterior margin of the peristomium extends over it. The palps 

 are separate from one another, and prominent, not sharply separated from 

 the prostomium, so that they seem almost to be forward prolongations of it. 

 Eyes 2 pairs, brown, anterior pair the larger and farther apart than posterior 

 pair. The median tentacle was noticeably more slender than the lateral and 

 none of these extends much beyond the tip of the palp. None of the tentacles 

 were well preserved and I am uncertain as to their normal appearance. 



Pharynx short, with ventrally a row of 8 subequal teeth. The peristomium 

 is prolonged dorsally into a broad lobe which covers the posterior surface of 

 the prostomium. Tentacular cirri are slender, the dorsal ones being the largest. 

 Dorsal cirri of later somites similar in form but successively smaller. 



Parapodium (plate 1, fig. 2), with its end prolonged into equal anterior and 

 posterior lobes and with an acicula with its apex coming to the surface just 

 dorsal to these. Ventral cirrus ovate in outline, shorter than setigerous lobe. 

 Dorsal cirrus long and slender. The setae (fig. 3) with a very long basal joint, 

 the longest reaching nearly halfway to the end of the dorsal cirrus. Terminal 

 joint with a very short terminal and a single subapical tooth. Apex of basal 

 portion with minute denticulations. 



Type in American Museum of Natural History. 



Collected at the Dry T ortugas in 1914. 



^Bulletin of the American Museum of Natural History, vol. 30. 



2.57 



