spec, USNM 86970), 4/II-6 7/76 (1 spec, USNM 86971); IXTOC S51-3 12/79 

 (1 spec, USNM 86967), S54-5 11/79 (1 spec, USNM 86968). 

 DESCRIPTION: 



Length, 19.0+ mm (previously reported to 40 mm); width, to 0.68 mm 

 (previously reported to 2.0 mm). Largest specimen incomplete with about 

 85 setigers. Prostomium (Figure 29-8a) with long, smooth, filiform 

 antennae; median antenna extending back, to about setiger 12. Palps with 

 small button-like palpostyles. Dorsal and ventral tentacular cirri 

 about equal in length. Dorsal cirri of setiger 1 extremely long, fili- 

 form (Figure 29-8a); subsequent ones shorter, tapering to pointed tips 

 (Figure 29-8a,b). Ventral cirri absent on setiger 2. Body with smooth 

 integument. Hooked acicular notosetae (Figure 29-8c) beginning on seti- 

 gers 10-15, accompanied by internal aciculum (Figure 29-8b) and occa- 

 sionally an emergent simple seta. Neurosetae tapering to fine tips, 

 serrate along one margin (Figure 29-8d); shorter neurosetae located 

 anteriorly within the neuropodial fascicle, with more distinct serra- 

 tions (Figure 29-8e). Pygidium with pair of long, filiform anal cirri. 

 REMARKS: Specimens from Gulf of Mexico BLM-0CS material fit quite well 

 the descriptions of Sigambra bassi by Hartman (1947b:501) and Pettibone 

 (1966:186). The only variation noted is that the hooked notosetae may 

 begin as early as setiger 10. 



PREVIOUSLY REPORTED HABITAT: Intertidal to 55 m; sand, sand mixed with 

 mud and shell fragments. 



GULF OF MEXICO BLM-OCS OCCURRENCE: Off Florida and Texas (Figure 29-7); 

 10-40 m; medium to fine-very fine sand, clayey sandy silt, sandy and 

 silty clay. 



DISTRIBUTION: North Carolina to Florida, Gulf of Mexico, southern 

 California. 



Genus Ancistrosyllis Mcintosh, 1879 



TYPE SPECIES: Ancistrosyllis groenlandica Mcintosh, 1879. 



REFERENCE: 



Pettibone, 1966:164. 



DIAGNOSIS: Palps not fused; palpostyles present. Two or three antennae 



present, each shorter than palps. One or two pairs of tentacular cirri. 



Acicular notosetae hooked. Neurosetae serrate, with minutely bifid 



tips. Pygidium papillose, with pair of anal cirri. Integument sparsely 



to heavily papillose. 



Key to the Gulf of Mexico BLM-OCS Species of Ancistrosyllis 



la. Ventral cirri present from setiger 1 (Figure 29-12a) 2 



lb. Ventral cirri present from a more posterior setiger 3 



2a. Notopodial hooks present from setiger 3 



Ancistrosyllis sp. A, p. 29-14 



2b. Notopodial hooks present from setiger 6 



Ancistrosyllis sp. B, p. 29-17 



3a. Ventral cirri present from setiger 2; median antenna absent. . . . 

 Ancistrosyllis carolinensis, p. 29-17 



29-12 



