Review of Labroides — Randall 
333 
might be termed roving carnivores and ap- 
pear to move over considerable distances. Yet 
they seemed to know the Labroides site, for 
they would come up to it from deeper water 
of the bay. At the atoll of Takaroa in the 
Tuamotus a four-foot moray eel ( Gymnothorax 
javanicus ) was seen to leave a hole in the 
coral, swim 15 feet over the bottom to a small 
coral head where a Labroides dimidiatus was 
located. There it was picked over the head and 
body by the labrid, after which it returned to 
the hole. Other fishes, such as Ctenochaetus 
striatus (Quoy and Gaimard), which were 
commonly seen being nibbled at by L. dimidi- 
atus , could not be distinguished from one 
another or identified as having come from a 
certain area; nevertheless, it is expected that 
some means of marking many such fishes in 
the area, such as with different colored tags, 
would demonstrate that these fish are aware 
of the place where the Labroides can be found 
and swim there, perhaps under the stimula- 
tion of being irritated by ectoparasites. Indi- 
vidual L. dimidiatus are not wholly dependent 
on fishes bearing parasites coming directly to 
them. Often the species has been observed 
swimming over the reef for distances as great 
as 60 feet "servicing” fishes on the way. This 
was especially true in areas where the highly 
territorial damsel fish Pomacentrus nigricans 
(Lacepede) was common. As one damsel fish 
was being tended, another nearby would as- 
sume a stationary pose with fins erect and the 
Labroides would move on to the latter with 
little hesitation. For further discussion of the 
subject of restricted "home” sites of Labro- 
ides , as applicable to L. phthirophagus , see the 
account of this species. 
The habit of feeding on ectoparasites is not 
unique to the genus Labroides , as might be 
surmised from the reference above to the 
labrid Iridio ( = Halichoeres) bivittatus of the 
Atlantic. Longley (in Longley and Hilde- 
brand, 1941: 129) reported that small pork- 
fish, Anisotremus virginicus (Linnaeus), nibble 
and peck at the surfaces of larger fishes at 
Tortugas. I was fortunate to observe one in- 
dividual of this species pecking at the body 
of the Nassau grouper, Epinephelus striatus 
(Bloch), in Florida, and can thus corroborate 
Longley’s observation. In addition, I saw a 
juvenile of the pomacentrid Microspathodon 
chrysyrus (Cuvier and Valenciennes) picking 
over the fins and body of an angel fish, 
Pomacanthus arcuatus (Linnaeus), which re- 
mained nearly motionless during the process. 
Also suspected of feeding on ectoparasites 
of fishes by Longley are the goby Llacatinus 
oceanops Jordan (p. 226) and the young of the 
labrid Thalassoma bifasciatum (Bloch) (p. 198). 
Of the former he wrote, "Wherever found, 
these small fish slip out from shelter, attach 
themselves by their ventral disks to other 
fishes, and 'creep’ over them, presumably to 
look for parasites. As many as 6 have been 
seen together on a Mycteroperca venenosa about 
% yard long. . . . The boldness of these tiny 
fish is almost incredible. They will creep over 
the teeth of the great Pseudoscams , or enter 
the mouths of grunts and groupers and ex- 
plore them with unhurried movements. . . . 
Their attentions usually continue until the 
larger fishes grow restless, start up abruptly, 
or move away and leave them, whereupon 
they return to their original stations.” 
Interestingly, the color of this goby is simi- 
lar to that of Labroides dimidiatus. E. oceanops 
which I observed in Florida were blue with 
a black longitudinal band running from the 
snout through the lower part of the eye, 
broadening on the body, and ending on 
ventral half of caudal fin. 
A recent paper by Eibl-Eibesfeldt (1955) 
is devoted in a large part to the detailed 
observation of the behavior of fishes which 
"cleanse” larger fishes. He observed the fol- 
lowing species in the Caribbean in symbiotic 
association with larger fishes: Elacatinus oce- 
anops , young Thalassoma bifasciatum , young 
Anisotremus virginicus , young Bodianus rufus 
(Linnaeus) (Labridae), and Gramma hemichry- 
sos Mowbray (Pseudochromidae). He noted 
that the larger fishes do not merely accept the 
cleansing but invite it by taking special posi- 
