NARRATIVE. 53 



pora, and Cribrilina). Most of the Polyzoa are strongly calcareous and brightly 

 coloured (scarlet) forms ; 



Crabs (porcelain white, two species (i) on the white branches of Chironvphthya), 

 and other small Crabs ; 



A new species of Chiton. (Tonicia pectinoides, Sykes), Harpa conoidalis, Strombus 

 succinctus, Murex tenuispinus, Murex haustellum, Conus betulinua, Natica mammilla, 

 Malleus vulgaris, Philine aperta (?) ; 



LeptocUnum sp., Rhodosoma sp., Styela sp., Molgula sp., Cynthia ('. n. sp.) ; 



A small banded Sole (Synaptura cornuta). 



Tow-net gatherings taken during the day were notable for the abundance of 

 Radiolaria, colonial as well as solitary Collozoum and others, also Trichodesmium 

 erythrceum, some pelagic planarians, Syllids, Halobates, Tornaria, and the Copepoda- 

 Centropages furcatus, C. gracilis and C. tenuiremis, n. sp., Calocalanus plvmosus, 

 Mecynocera clausi, Oithona plumifera, and about 20 others. 



Although the depths were greater than that of the paars further north, it is 

 important to note that the bottoms at several of these localities off Mount Lavinia 

 and elsewhere south of Colombo were hard, clean, and apparently very suitable for 

 the attachment of pearl oysters, being largely formed of the same balls of Nullipore 

 (IAthoihamnion fruticulosum) which characterise the paars in the Gulf of Manaar. 

 It is very probable that this bottom extends into shallower water, and that suitable 

 spots may be found nearer shore upon which the pearl oyster might be cultivated. 

 It is said that a pearl oyster bank once existed off Mount Lavinia. 



On the evening of February 19th we arrived at Colombo. In this first cruise in 

 the s.s. " Lady Havelock," in addition to making a preliminary survey of the more 

 important pearl oyster banks, we had sampled the bottom conditions and the fauna at 

 various points round the island, and had made a special examination of the several 

 localities (Palk Bay, Trincomalee and Galle) to which our attention had become 

 directed. We had also considered these last and other localities very carefully with 

 the view of choosing the best site for a small marine laboratory in which to carry on 

 investigations and experiments with the pearl oyster. Our conclusion at the end of 

 the cruise was that of all the places seen in coasting round the island only two would 

 be at all suitable for this purpose, viz., Trincomalee and Galle. 



Of these, Trincomalee has the distinct advantages of (1) complete shelter from the 

 monsoons, and (2) natural beds of pearl oysters living in the harbour; but on the 

 other hand the following may be noted as more or less serious objections : 



(1.) The specific gravity of the water is low, between 1"019 and I "021 as compared 



with T023, the usual reading in the Gulf of Manaar ; 

 (2.) The plankton at the time of our observations seemed sparse compared with 



that at Galle and in the Gulf of Manaar ; 

 (3.) The distance, and therefore the time necessary in taking live oysters round, 



from the Gulf of Manaar is much greater. In the case of Trincomalee a 



