relative blade lengths of anterior composite falcigers appear to be a 

 more reliable character for separating these species. 



PREVIOUSLY REPORTED HABITAT: To 20 ra; coarse calcareous sand; sand, 

 broken shell. 



GULF OF MEXICO BLM-OCS OCCURRENCE: Two stations off northwestern Flori- 

 da (Figure 30-25); 19-45 m; coarse sand, silty fine sand. 

 DISTRIBUTION: North Carolina, Florida, Gulf of Mexico. 



Genus Exogone Oersted, 1845 



TYPE SPECIES: Exogone naidina Oersted, 1845. 



REFERENCES: 



Imajima, 1966:395. 



Day, 1967:271. 



Fauchald, 1977a:82. 



DIAGNOSIS: Prostomium with three antennae; palps fused dorsally 



throughout most or entire length. One pair of tentacular cirri. Nuchal 



organs inconspicuous. Tentacular, dorsal, and ventral cirri ovoid. 



Pharynx armed with single dorsal tooth. Developing young attached 



caudally to ventrum of medial segments of female. 



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



la. Median antennae same length as lateral antennae (Figure 30-28a); 



dorsal cirri absent on setiger 2. . . .Exogone atlantica, p. 30-34 

 lb. Median antenna longer than lateral antennae; dorsal cirri present 



or absent on setiger 2 2 



2a. Long-bladed composite setae with minutely bidentate tips (Figure 



30-30c); superior simple seta aristate (Figure 30-30b) 



Exogone sp. A, p. 30-37 



2b. Long-bladed composite setae with entire tips; superior simple seta 

 sharp- or blunt-tipped, not aristate 3 



3a. Dorsal cirri absent on setiger 2; short-bladed composite falcigers 

 unidentate (Figure 30-32d) Exogone sp. B, p. 30-39 



3b. Dorsal cirri present on setiger 2; short-bladed composite falci- 

 gers bidentate (Figure 30-34e) 4 



4a. Composite spinigers of setiger 2 with greatly enlarged shaft-heads 

 (Figure 30-34d) Exogone lourei, p. 30-39 



4b. Composite spinigers of setiger 2 without enlarged shaft-heads 

 (Figure 30-36c) Exogone dispar, p. 30-43 



Exogone atlantica Perkins, 1981 

 Figures 30-27, 28a-e 



Exogone atlantica Perkins, 1981:1097, fig. 7a-i. 



MATERIAL EXAMINED: 



Gulf of Mexico BLM-OCS: 



SOFLA 16B-11/80 (3 spec, USNM 75282), 16A-4/81 (5 spec, USNM 75281), 



30-34 



