126 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



undulating elongated ridge with conspicuous summits (volcanic 1), one of 

 which is over six hundred feet high ; it is a little over six miles in 

 length, and situated at the northwestern extremity of an elongated 

 plateau extending fifteen miles in a southeasterly direction, with an av- 

 erage depth of thirty to over forty fathoms. The western extremity of 

 Thikombia, as well as the southern half of the island, is bordered by a 

 fringing reef, which extends in a long spit made up of patches and 

 detached rocks for two and a half miles in a southeasterly direction. 

 Gardiner states that parts of Thikombia are terraced. 



Ono i lau. 



Plate 17", Figs. 13-16, and Plate 33% Figs. 1-4. 



We did not visit the islands to the south of Ongea. Among them 

 are the Ono i lau Islands (Plate 1), of which some are volcanic and 

 others composed of elevated coralliferous limestone, the highest island 

 being 370 feet high. These islands are surrounded by an outer reef 

 flat, elliptical in outline, about seven miles by four, which is dotted 

 with islets, rocks, and coral patches. To the south of these islands are 

 the small islands of Tuvana i tholo and Tuvana i ra (Plate 17% Fig. 

 13, and Plate 23% Fig. 27), situated on the northern edges of the 

 circular barrier reef which surrounds them. To the southwest of the 

 Ono cluster lies Vuata Ono (Plate 17% Fig. U, and Plate 23%Fig. 3), 

 an oblong reef nearly three miles long and always awash. Turtle 

 Island to the northeast of Ono is a narrow ridge of elevated limestone, 

 rising to over two hundred feet, with a barrier reef about four miles 

 long off the west face, enclosing a narrow lagoon with six fathoms of 

 water and passing into a barrier reef on the east face. Yuata Yatoa 

 (Plate 23% Fig. 4) is a detached reef somewhat over two miles in its 

 greatest length, enclosing a tidal basin into which there is a boat passage 

 through the reef. This reef lies about two miles to the south of Yatoa, 

 with two hundred and forty-six fathoms in mid-channel. Yatoa and 

 Yuata Yatoa are probably the summits of a short ridge. The presence 

 of elevated coralliferous limestone in this part of Fiji shows that the 

 area of elevation of the group extended to the southernmost islands. 



Viti Levu and Vanua Levu. 



Plates 3, 3", 4, 18. 



Although there are large stretches of the shores of Viti Levu and of 

 Vanua Levu (Plates 3, 3% 4) which I have not examined, we may per- 



