276 A NATURALIST ON THE "CHALLENGER.' 



Delightful though it was at Sydney to make so many friends 

 amongst one's countrymen, after so long a voyage from home, 

 and to enjoy their far-famed hospitality, one could not as a 

 naturalist, help feeling a lurking regret that matters were not 

 stiii in the same condition as in the days of Captain Cook, and 

 the colonists replaced by the race which they have ousted and 

 destroyed, a race far more interesting and original from an 

 anthropological point of view. 



Whilst we were at Sydney, the ship's steam pinnace was 

 constantly employed in dredging for Trigonia shells in Port 

 Jackson. These shells, in shape very like cockles, are imme- 

 diately known by their brilliant pearly lustre within, and curious 

 complicated hinges. They vary very much in the tint of the 

 nacre inside. Some are orange-tinted, others pink or purple, 

 some without colour. The shells are worn very much by the 

 ladies of Sydney, as earrings and other ornaments, being set in 

 gold. 



The shell is especially interesting to the naturalist, because 

 it occurs fossil in secondary deposits in Europe, and was long 

 supposed entirely a thing of the past, until discovered living 

 in Sydney Harbour. Moreover, with it occurs in the harbour a 

 most remarkable fish, the Port Jackson Shark (Cestracion Phi- 

 lippi) which is also closely allied to fish, remains of which are 

 found in the deposits together with the Trigonias. 



It was believed for some time that the modern Trigonias 

 were very restricted in their distribution. A species occurs 

 however at Cape York, and Mr. S. C. J. W. van Musschenbrook, 

 Governor of Ternate in the Moluccas, told me that he had 

 obtained specimens of the genus from the coast of Halmahera 

 (Gilolo). A Port Jackson Shark is also found far away from 

 Australia, in the Japanese seas, and at intermediate localities. 



