32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



(fig. 7). The observed range extends from the shoreward edge of the 

 White Bank to the sand patches just shoreward of the main reef (the 

 area termed the interreef deep channel). Depths at which living speci- 

 mens were found range from 10-25 feet, although dead tests were 

 found on banks as shallow as 3 feet, and in the sand offshore from the 

 reef at station 17a at 85 feet. 



This species was found at stations 11a (dead), 17a (dead), (20) 

 (dead), 23, 30, 39 (dead), 44, 45, 49, 55, 56, and 57. 



Behavior. — Leodia sexiesperforata moves anteriorly through the 

 sand at a depth of about 1 inch below the surface, just slightly deeper 

 than the observed depth of burrowing of Encope michelini. Goodbody 

 (1960, p. 80) observed the species near Jamaica at times burrowing 

 so shallowly that its outline was discernible from above, and at other 

 times burrowing somewhat deeper. The individual moves forward 

 by means of locomotor spines which occur around the periphery of 

 the test and in concentrations in the interambulacral areas of the 

 ventral surface. The dorsal surface is covered with numerous short, 

 club-shaped spines, and slightly shorter mucus-secreting spines 

 (Goodbody, 1960, p. 83). These are used to pass sand grains up onto 

 the dorsal surface. When a specimen is excavated from the sand it 

 reburies itself in 5 to 7 minutes, normally accomplishing complete 

 burial before having moved anteriorly more than one-half its own 

 length. Burial is achieved partly by pushing forward into the sand, 

 but mostly by passing sand grains onto the dorsal surface by the two 

 kinds of spines. The grains are moved up along the anterior and the 

 anterolateral edges, and passed backward over the test in two sheets 

 which coalesce over the middle of the test (pi. 7, figs. 6-8). A few 

 grains appear to be passed upward through the lunules, but these do 

 not seem to play a large part in covering the test with sand. 



Leodia sexiesperforata rights itself after being overturned by mov- 

 ing anteriorly or slightly anterolateral^ into the sand. Locomotor 

 spines are most densely concentrated along the anterior peripheral 

 edge and in the two anterolateral interambulacral areas of the ventral 

 surface (Goodbody, 1960, fig. 1). Action of these spines tends to move 

 the oral surface into the sand at an increasingly steep angle until the 

 test is vertical. Then the animal continues its forward motion and, by 

 the aid of gravity, it is rapidly righted from the vertical position, and 

 buried almost concurrently. 



Goodbody (1960) described the mechanism by which food particles 

 are moved toward the mouth of this species. Cilia at the bases of the 

 club-shaped and the mucus-secreting spines on the dorsal surface set 



