244 TONGATABU. 



In this case, Mr. Lankester accounts for the presence of the 

 HceDioglobin in the dorsal fin muscles only by the special 

 activity of the fin in question, but such an explanation fails in 

 the case of the shark, the skin of which is apparently immov- 

 able ; moreover, the structure of the skin precludes the idea of 

 the red matter beneath it having a respiratory function. 



Mr. Lankester has shown that Hczmoglobin is entirely wanting 

 in one fish at least, the white transparent oceanic surface 

 fish Leptocephahis ; and I believe that small oceanic Flat-fish, 

 {Pleuronectid), will prove also to be devoid of red-blood 

 colouring. 



I was extremely vexed that no landing on the Kermadec 

 Islands was arranged. Further information concerning the 

 flora of the islands is very much wanted, and it seemed hard 

 to be dredging off the islands and not to be able to land. 



Tongatabu, July 19th to July 22nd, 1874.— Our approach to 

 the Friendly Islands group was heralded by the appearance of 

 a Tropic Bird, which was seen flying behind the ship, although 

 we were as yet 150 miles distant from Tongatabu. 



We sighted the island of Eua in early morning, and passed 

 to the north of it. It is elevated in its highest point 600 

 feet above the sea, and is volcanic, with coral rock at its 

 base. An ancient, now upraised sea-cliff of the coral rock, 

 is conspicuous from the distance, forming a line above the 

 present coast-cliff, as described by Dana.* 



The island appears covered with bushes, with very few trees, 

 and isolated palms on the summits of the high ground. The 

 bushes on the higher land appear to be all bent over in the 

 direction of the trade wind. 



The sky was dull, covered with grey clouds, and the air even 

 somewhat chilly, so the islands did not look bright and sun- 

 shiny, as I had expected these, the first South Sea Islands I 

 had seen, to look. At the base of the Eua, the surf in places 

 raised jets of spray, looking from a distance like thin white 

 smoke. 



Tongatabu was seen seven miles distant from the small Eua, 

 stretched along the horizon as a long narrow neutral tint band, 

 with an indented upper margin : towards the northern end 

 the band thinned out into isolated rows and groups of palm- 

 trees, which looked like dots on the watery horizon. As we 

 approached nearer, the forms of the cocoanut-trees became 

 more and more distinct. At length we shortened sail and 

 steamed through the reefs with a long stretch of palm-covered 

 land on the one hand, and numerous islets on the other, some 

 bearing many cocoanut palms, others with few. 



* J. D. Dana, " Coral Rctfs and Islands," p. 30. 



