106 "ALBATROSS" TROPICAL PACIFIC EXPEDITION. 



The surface hauls made inside the lagoon proved comparatively poor: 

 a few Copepods, larvae of Macruraiis and Brachiurans, young fishes, a few 

 Appendicularise and Sagittaa, and a small Geryonia, — a mixture of pelagic 

 surface life and of littoral pelagic larvae. 



We examined the rocky shoals to the northward of the ship, — one about 

 two, the other four miles from the anchorage ; we found them both to be 

 fragments of the old ledge. At the first ledge there is, at a distance of from 

 70 to 80 feet from the flat edge of the ledge, a depth of 12 fathoms, which thus 

 slopes very rapidly on all sides. Fragments of the ledge have broken off 

 and rolled down, forming a talus ; and on the slopes thus formed corals of 

 all kinds have established themselves. On the second ledge quite a small 

 island of old ledge is left standing about five feet in height, irregular in 

 shape, with a diameter of ten to twelve feet. The flat part of both these 

 ledges is a shoal of some length, covered with fragments of the old ledge 

 and overgrown with Nullipores covering also masses of dead shells and frag- 

 ments of corals which fill the interstices of the larger masses, so that the 

 whole surface of the shoal presents a highly colored appearance, varying from 

 yellovpish to pink and red, or dark violet, much as the wide reef flat of the 

 south shore was colored by its covering of Nullipores, corallines, and corals. 



On the slopes of these ledges grow masses of corals, of Madrepores, 

 Pocillipores, Goniastrseas, of heads of several species of Porites, with 

 differently colored Astraeans, and masses of algae and corallines growing 

 between the heads, and Nullipores encrusting the smaller fragments and 

 cementing the parts into a solid mass. On the lee side of both these 

 ledges, the boulders and loose material formed a regular talus on the face 

 of which but few corals were growing. The corals extended to about ten 

 fathoms, when they were in great part replaced by Nullipores and corallines, 

 and finally coral and coralline sand and fragments of broken corals occupied 

 the bottom of the lagoon from sixteen fathoms down. 



In eight fathoms, about three fourths of a mile from shore, Alveopora is 

 ver}^ common, growing upon old fragments of corals covered by algae and 

 corallines. On the greater part of the shoals, in rather shallow water, Mille- 

 pores grow in great abundance. In 2^ fathoms we found fragments of beach 

 rock and of old ledge covered by Nullipores and running inshore to connect 



