NO. 6 ECHINOID DISTRIBUTION AND HABITS KIER, GRANT 21 



are classed as separate species. For purposes of this paper they are 

 considered separate, following Mortensen (1943, p. 365). 



The one specimen that was found at the depth of 40 feet was in an 

 elongate hole in the edge of a spur on the offshore side of the main 

 reef (station 37). Although the specimen was difficult to remove from 

 its niche, the aperture of the hole appeared to be sufficiently large to 

 allow the animal to enter and leave freely. 



Genus LYTECHINUS Agassiz 

 LYTECHINUS VARIEGATUS (Lamarck) 



Plate 3, figure 1 ; text figure 5 



The color of the test and spines of this species ranges from green, 

 to red, purple, or white. An adult is approximately 90 mm. in hori- 

 zontal diameter with spines. The bare test is high domed with 

 smoothly curving sides, and a relatively small peristome. The ambu- 

 lacra are moderately wide with the pore-pairs arranged in two series 

 in each ambulacrum ; each series with the pore-pairs in units of three. 

 The pedicellariae are very conspicuous on a living specimen. The 

 tubercles in the interambulacra are small and arranged in horizontal 

 rows with approximately four in each half-interambulacrum. This 

 species is distinguished from Tripneustes ventricosus, a species asso- 

 ciated with it and somewhat similar in appearance, by its generally 

 smaller test, variable color, more conspicuous pedicellariae, more 

 numerous and shorter spines, and more compactly arranged pore-pairs 

 in each poriferous zone. 



Occurrence. — Lyt echinus variegatus was abundant in areas of 

 turtle grass, rare on bare sand near turtle grass and on alga encrusted 

 rock along the shoreline, and absent from broad expanses of clean, 

 grassless sand. It occurred in water ranging in depth from about 4 to 

 35 feet (fig. 5). Sharp and Gray (1962, p. 309) report its presence 

 on shelly sand bottom off the coast of North Carolina, and its absence 

 from grassy areas. Our findings are more similar to those of Clark 

 (1933) who found this species in grass off Puerto Rico, and Moore, 

 et al. (1963) who also found it in grass and absent from clean sand 

 or gravel off Key Largo. Clark (1933) found juveniles living under 

 and among rocks outside of grassy areas. We found them living 

 similarly, along with juveniles of Tripneustes ventricosus, in sandy 

 areas near grass patches, clustered together in aggregates of shells, 

 algae, and especially small sponges. Extensive search of the adjacent 

 grassy areas revealed only one juvenile L. variegatus. 



