564 Transactions, 



Sargassum Belt. — The lowest, tract of the emerging belt being exposed 

 only at low spring tides, and constantly bathed by wave-action, is included 

 in the belt of large brown algae extending to 1 m. or more below low-tide 

 mark. This rocky belt, having a maximum quantity of light, supports a 

 rich fauna and flora of a distinctly hydrophilous character. A number 

 of large molluscs in no way protected against desiccation are found here. 

 Such are Polypus oliveri, Umbraculum umbella, and many Aplysioids ; to 

 which should be added those molluscs which cannot draw into their shell 

 behind an operculum, as Conus kermadecensis, Siphonaria cheesemani, and 

 Cypraea. The large limpet Scutellastra kermadecensis, which must require 

 a constant supply of food, is characteristic of this belt, in places almost 

 covering the rocks. Its massive shell is rather a protection against pre- 

 dacious fishes than desiccation. Other large species found in this belt 

 are Charonia lampas. Argobuccinum australasia, Neothais succincta, Eudoxo- 

 chiton perplexus, and occasionally Tectus royanus. The dominant algae 

 are Sargassum fissifolium and Pterocladia capillacea, the latter supporting 

 in great abundance the small bivalve Philobrya meleagrina. 



Under Stones. — With light absent or weak, and the presence of mud and 

 sand, this habitat supports a distinctive fauna, composed of sponges, sea- 

 anemones, worms, echinoderms, and molluscs. No algae were collected 

 on the underside of rocks, except near the edges. The molluscs include 

 four species of Amphineura, some small Gastropods (Columbella versicolor, 

 Gadinea conica, Vanikoro wallacei, Rissoina angasi, Clanculus atypicus, and 

 others), and the bivalves Area reticulata and Codakia bella. 



Sea-bottom. 



Rocks near Shore. — In this belt, which extends from the Sargassum belt 

 down for a few fathoms, the dominant fixed animals are corals and com- 

 pound Ascidiaris. This is a difficult tract to investigate, as a dredge cannot 

 be used. It is extremely rich in many kinds of animal life, and through a 

 water-telescope presents a magnificent sight. Tectus royanus is abundant, 

 while on coral Magilus antiquus and Quoyula madreporarium are plentiful. 

 There can be little doubt that the large number of species of shells recorded 

 in this paper as dredged on gravelly bottom and as found washed up on 

 the beaches live among rocks below low-water mark. 



Sand and Gravel.— A few live shells were dredged near Sunday Island 

 on sand and gravel in 10 m. to 30 m. They include Xenophora corrugata, 

 Fusinus toreuma, Terebra circumcincta, Pecten medius, Protocardia pulchella, 

 and, attached to pumice, Spondylus raoulensis. 



Surface of Ocean. 



Plankton. — Situated in a vast expanse of ocean, Sunday Island, as might 

 be supposed, frequently has cast up on its shore pelagic animals. Some- 

 times, as with Ianthina, Spirula, Velella, and Physalia, they are washed 

 up in large numbers. Pelagic molluscs recorded in the present list include 

 four species of Ianthina, Recluzia lutea, fourteen species of Pteropods, and 

 several Cephalopods. 



Floating Logs. — Besides numerous stalked cirripedes, crabs, and worms, 

 there were found in logs cast up on the beaches Saxicava arctica and Nausi- 

 toria aurila, while Uperotis clava was taken from coconuts. 



