106 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



the ship " Wansfell." In 1864 she passed into the reef through an 

 unknown opening about latitude 20° 30' S., and came out opposite 

 Port Denison. 



As we proceed northward, corals become more and more abundant, 

 skirting parts of the islands from which too great quantities of detritus 

 are not washed down in the rainy season, or wherever a locality presents 

 itself, favorably placed as regards the food supply or the purity and 

 depth of the water. 



On our way north from Keppel Bay we could only examine the 

 numerous islands we passed in the most superficial manner. The state 

 of the sea prevented us from landing either at any of the Northum- 

 berland Islands, or the Percy Islands, or the southern group of the 

 Cumberland Islands. It was only when we reached the southern 

 extremity of Whitsunday Passage (Plate XXX.) that we were able to 

 examine the small reefs which skii't part of the shores of the greater 

 number of the larger islands forming the eastern belt of the passage. 



The bank in Cid Harbor (Whitsunday Island) to the north of our 

 anchorage, which slopes gradually from the shore to two or three 

 fathoms, was covered by fine masses of coral. They apparently did 

 not stretch into deep water, for near our anchorage, which was in only 

 six fathoms, there wei'e no corals, the bottom being mud and broken 

 shells. The corals formed a belt (a kind of plateau) of a certain width 

 on the slope. The Astrreans were marked for their size. Huge masses 

 of whitish Alcyonaria were very active, the long-stemmed individuals 

 of the colony twisting and bending in all directions. The abundance 

 of soft masses of Alcyonaria seems to be a characteristic of the coral 

 reefs of Australia, where they replace the Gorgonians of the West 

 Indian reefs. The masses of Astrzeans, of Mseandrinas, and of Porites 

 were also uniformly larger than we find them on the West Indian coral 

 reefs. Between the heads were buried Tridacnas of varying sizes, and 

 sponges were also far more common than is the case in the West 

 Indian reefs. 



At Langford Island (Plate XVIII.), a small island at the northern 

 extremity of Whitsunday Passage, we examined the coral reef which 

 extends for about a mile to the south and east of the island. The two 

 extremities of Langford Island arc connected by a sandbar, and on the 

 slopes of the reef flat, which is bare at low water, corals flourish in 

 from two to three fathoms. At the southern extremity of the reef flat 

 are two low islands, the remnants of the spit which once connected 

 them with the higher island at the other end of the reef flat. The 



