104 "ALBA.TROSS" TROPICAL PACIFIC EXPEDITION. 



over the highest point of the beach and rolls inland (PI. 59, fig. 1). At the 

 base of the beach the shingle has been ground to fine coral sand. From the 

 base of this extends the rather narrow reef flat from 50 to 75 feet wide ; 

 this is somewhat dished, forming an irregular ditch flanked on the sea face 

 by a wall of Nullipore and Pocillipore knolls in places fully four feet higher 

 than the reef flat sink (PI. 60, fig. 3). The large island on the north side of 

 Makemo Pass is from 1000 to 1200 feet in width. 



A line of soundings was made in the lagoon by one of the officers (Mr. 

 Kempff). He brought back a number of samples of the bottom ; they are 

 most uniform in character, consisting of coral sand, coral fragments, broken 

 shells, plates and spines of sea urchins, fragments of Nullipores, corallines, 

 Orbitolites, and other Foraminifera. The greatest depth thus far found while 

 surveying in the lagoon is 16 fathoms. A great many islets, shoals, bars, 

 and ledges are to be seen cropping out in all directions.' 



We went in the steam launch acro.ss the lagoon towards the nearest point 

 of the south side ; we made a few soundings, going over, in from eight 

 to ten fathoms ; we usually found hard bottom, with Nullipore and coralhne 

 patches or corals, extending from the slopes of the numerous shoals we found 

 on the way. On shoals having from two to three feet of water at low tide 

 we found the top covered with dead coral heads more or less overgrown with 

 Nullipores, while on the edges of the slopes began to grow Madrepores and 

 Millepores, with heads of Pocillipores extending into deep water. The top 

 of one of the largest shoals we found, fully a mile in length, was covered 

 with dead corals encrusted by Nullipores and overgrown with algae and coral- 

 lines, with scattered patches of thriving corals dotted over the surface and 

 extending over the slopes towards the bottom of the lagoon. 



The approach to the lagoon edge of the south shore reef flat is very grad- 

 ual from the ten-fathom line, which is at a distance of from 1000 to 1500 



• An Ecliinoneus of a pinkish color, varying to light chestnut, was collected on the outer reef ; the 

 smallest specimen, measuring one fourth of an inch, was pinkish. The peiiicellariae and tentacles are of 

 a (lark violet. The pigmented rows of suckers stand out ijrominentl)- from the rest of the test as dark 

 violet lines. The covering of the glassy tubercles is only a continuation of the epithelial surface, similar 

 to that on the base of the spines, only without pigment spots. The tentacles near the apical system have 

 a rudimentary sucker, which is more developed on the actinal face. The genital openings are protected 

 by small spines. The plates of the anal system are somewhat imbricated ; those of the mouth very- 

 much so. 



