500 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1956 



constantly patrolling it for food. Certain surgeonfishes also are char- 

 acteristic of the surf zone, among them Acanthurus lineatus, a yellow 

 and neon-blue striped fish that loves turbulent, surging water. Their 

 relatives, the fan-finned zebrasomas, hide under the spreading table 

 corals. Huge parrotfishes, six or more feet in length, graze like 

 cattle upon the corals, producing a noisy chorus as they crunch their 

 limy meals in large, gregarious schools. Moray eels (Gynmothorax) 

 lie in wait in their holes, their malicious eyes alert for any unwary 

 fish that may pass within striking distance. The butterflyfishes 

 (Ghaetodon), so named because of their brilliant coloration, are 

 especially numerous and are endowed with an insatiable curiosity. 

 They seem unafraid of divers and will approach very close in order 

 to get a good look. On many occasions they have startled us by a 

 quick nip or a tug on some especially attractive hair. This has an 

 electrifying effect upon swimmers already fearful of a surprise attack 

 by prowling sharks, and the sheepish feeling combined with relief 

 upon seeing these small challengers, is more amusing now than it 

 was on the reef. 



The spiny lobsters (Panulirus) that lurk in crevices of the outer reef 

 are different species from those found in the lagoon. So are the coral 

 crabs (Trapezia) among the massive branches of pocilloporas, veri- 

 table giants by comparison with their relatives in more protected 

 waters. 



Any specimens taken from the surf zone are collected only through 

 great exertion, for it is one of the most difficult habitats to sample. 

 Swift currents rapidly dissipate the rotenone and sweep away the speci- 

 mens killed by it. The collector himself may be picked up by the 

 swell and dropped 15 or 20 feet away, as likely as not on a jagged 

 coral. "When explosives are used instead of rotenone, all the nearby 

 sharks materialize as if from nowhere, considering its sound a dinner 

 bell inviting them to a free meal. Needless to say, we used this explo- 

 sive technique infrequently, so as to avoid becoming the piece de 

 resistance of some shark's luncheon. 



Near the reef passes and in the deeper waters offshore the corals 

 flourish in stony gardens of eerie and awesome beauty. Some species 

 of Acropora produce towering spires and antlers (pi. 7, fig. 1) that 

 bring to mind the reefs made by the same genus of corals in the West 

 Indies, and others form great, spreading disks and platforms com- 

 posed of tiny branchlets, a growth form peculiar to the Indo-Pacific 

 area (pi. 13). The sea gardens of swaying alcyonarians (sea-fans 

 and sea- whips) that give the West Indian reefs their color and fluid 

 beauty are nowhere to be seen, for the alcyonarians here are nearly all 

 massive, rubbery kinds (pi. 13, fig. 2) that have not the elegance of 

 their Caribbean relatives. The few species of sea-fans that do occur 



