PREVIOUSLY REPORTED HABITAT: II ra; coarse calcareous sand. 



GULF OF MEXICO BLM-OCS OCCURRENCE: Widespread in northeastern Gulf and 



one station off Texas (Figure 30-95); 10-168 m; coarse to very fine 



sand, silty fine to very fine sand. 



DISTRIBUTION: East coast of Florida, Gulf of Mexico. 



Genus Opisthosyllis Langerhans, 1879 



TYPE SPECIES: Opisthosyllis brunnea Langerhans, 1879. 



REFERENCES: 



Imajima, 1966:223. 



Day, 1967:252. 



Fauchald, 1977a:83. 



DIAGNOSIS: Prostoraiura with three antennae. Occipital flap present or 



absent. Nuchal organs as small, ciliated lobes between prostomium and 



peristoraium. Two pairs of tentacular cirri. Antennae, tentacular and 



dorsal cirri articled. Pharynx with smooth margin, middorsal tooth 



located medially. 



Opisthosyllis sp. A 



Figures 30-97, 98a-f 



MATERIAL EXAMINED: 

 Gulf of Mexico BLM-OCS: 



SOFLA 4B-7/81 (1 spec, USNM 75295); MAFLA 2211G-8/77 (1 spec), 2211F- 

 2/78 (1 spec, USNM 65678; 1 spec). 

 DESCRIPTION: 



Length, to 22.8 mm; width, to 0.6 mm. Body long, slender; complete 

 specimen with 106 setigers. Prostomium rounded, with four lentigerous 

 eyes, and 1-2 ocular spots at base of palps (Figure 30-98a). Median 

 antenna with 11-13 articles, lateral antennae with 8-12 articles. Palps 

 moderately long, triangular, fused basally. Dorsal tentacular cirri 

 with 12-17 articles, ventral ones with 9-11 articles. Dorsal cirri 

 long, slender, with 8-24 articles; alternating slightly in length. 

 Ventral cirri digitiform, usually extending beyond parapodia. Composite 

 falcigers with bidentate blades having fine to coarse serrations, and 

 distal teeth set close together (Figure 30-98b-d); blade-length ratios 

 1.7-2:1 anteriorly, 1.9-2.2:1 medially, 2:1 posteriorly. Superior sim- 

 ple seta minutely bifid (Figure 30-98e); inferior simple seta bidentate 

 (Figure 30-98f); both present only on far posterior setigers. Pharynx 

 extending to setigers 7-8, with massive, acutely pointed, middorsal 

 tooth located medially. Proventricle extending from setigers 8-9 to 10- 

 11, with 23-27 muscle cell rows. Ventricle long, convoluted (Figure 30- 

 98a), occupying 6-8 setigers. Pharynx 1.3-1.9 times length of proven- 

 tricle; proventricle 2.5-2.9 times longer than wide. 



REMARKS: Opisthosyllis sp. A was confused with Syllides in BLM-MAFLA 

 collections. 



GULF OF MEXICO BLM-OCS OCCURRENCE: Two stations off central Florida 

 (Figure 30-97); 43-56 m, coarse to medium sand. 



30-103 



