122 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
feet. It resembles Naiau on a smaller scale. It is surrounded as is 
Tuvuthé by a narrow outer reef flat, becoming a fringing reef at several 
points of the shore, and enclosing a narrow and shallow lagoon full of 
rocks and patches. 
There are also a number of atolls presenting no special features. To 
the westward of Ngele Levu are two reefs, Thakau Vutho Vutho 
and Thakau Mata Thuthu (Plate 17). The former is separated from 
Ngele Levu by a channel eight miles wide, with 145 fathoms in mid- 
channel. The latter is separated from Thakau Vutho Vutho by a 
channel 171 fathoms deep and three miles wide. The lagoons have 
respectively a greatest depth of 15 and 19 fathoms. They both have 
navigable entrances, and the outer reef flats are studded with negro- 
heads and coral patches, and there are no islands on the rim. These 
atolls resemble Ngele Levu, but are not more than one third of its size. 
It is interesting to note that to the westward of Thakau Mata Thuthu 
(Plate 17) there is an isolated bank with 74 and 76 fathoms of water, 
but separated from it by a narrow channel; it may be a spur of the 
bank upon which the atoll of Thakau Mata Thuthu is situated, similar 
to Cock’s Bank, which is close to the southwestern edge of the 100 
fathom line. 
Similar atolls and varying greatly in shape are Duff’s Reef (Plate 18) 
to the west of Wailangilala, and to the south Dibble’s Reef (Plate 19), 
to the east of Vanua Mbalavu, Nuku Thikombia (Plate 19), and Male- 
vuvu Reef (Plate 19) ; farther south Thakau Tambu, Yaroua, and the 
smaller reefs Thakaun Nokeva and Thakau Lasemarawa (Plate 20). 
As we steamed from Tuvuthé to Naiau we saw the sandbank in the 
centre of Tavanuku i vanua Reef surrounded by a fringing reef somewhat 
more than a third of a mile in width (Plate 20). To the southwest of 
Tuvuthaé is also situated a small circular atoll, Tavanuku i wai, with 
an outer reef of about half a mile in diameter enclosing a small shallow 
lagoon. 
To the east of Mothe are Thakau Motu (Plate 22), a large atoll open 
to the west, with 24 fathoms in the deepest part of the lagoon (Plate 
23*, Fig. 6), and Thakau Vau (Plate 22), a small circular reef with a 
shallow lagoon of impounded water. Neither of these did we visit. West 
of Komo, Thakau Vuite (Plate 22), in a line running north and south, 
east of the Yangas4 cluster, lies Thakau Levu, and southwest of Vanua 
Vatu and to the northeast of Totoya the Tova or Na Vatu Reef (Plate 
23*, Fig. 5, and Plate 20%, Figs. 13, 14). Tova has been well surveyed 
(Plate 20%, Figs. 15, 14, and Plate 23%, Fig. 5) ; unfortunately we were 
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