30 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Murray, who visited Kandavu in the ‘ Challenger,” considers the 
banks of Fiji surrounding the extremities of volcanic islands as banks 
formed from the loose material of the islands spread out laterally by 
wave action, the extensive banks extending much farther seaward 
there in one direction than in another. Murray has also called attention 
to the North Astrolabe Reef, which, if its present condition with Solo 
Rock in the centre is due to subsidence, should have a very much deeper 
lagoon, instead of the comparatively shallow one characterizing that 
reef. 
Great Astrolabe Reef. 
Plates 11, 11°, Figs. 10-13, and Plates 51, 52. 
To the northward of the eastern extremity of Kandava (Plate 11) ex- 
tends the Great Astrolabe Reef. Its eastern face is the extension of 
the reef to the eastward of Tomba ni Soso (Plate 10), an irregularly 
shaped bay, the mouth of which is protected by a barrier reef. This 
barrier reef extends as a fringing reef along the southern coast as far 
as Kandavu Bay, where it becomes separated from the island and forms 
stretches of barrier reef patches, with passages leading into the bays 
protected by the reef. 
West of the entrance to Ngoala Harbor a broad fringing reef extends 
along the southern coast nearly to the western spit of Kandavu. Sev- 
eral reef harbors are cut out from it, one of which, Tomba Yauravu, is of 
considerable size (Plate 10). From Naingoro Pass the outer reef of the 
Great Astrolabe Reef runs unbroken in a northerly direction for a dis- 
tance of 25 miles round its northern horn, as far as Usborne Pass, which 
is an entrance into the lagoon on the western side, about a mile from the 
apex of the Great Astrolabe Reef. Off Mbulia, the easternmost of the 
islands inside the Great Astrolabe Reef, the eastern encircling reef 
makes a sharp elbow, and then forms a double curve in a northwesterly 
direction to the narrow apex, from which the reef turns sharply south 
as far as Alacrity Rocks in a great narrow are broken in many places. 
North of Ono Island there are three well defined passages, but south of 
Alacrity Pass the reef becomes much broken up into small patches, 
and finally, from Ono Island south the lagoon is open, and has a steep 
slope towards the 100 fathom line. 
The depth of the lagoon north of Ono is not more than twenty-two 
fathoms ; the bottom is most uneven, often passing rapidly from five 
1 Nature, July 4, 1889, p. 222. 
