ANATOMY AND LIFE HISTORY OP MOLLUSCA. 109 



contribute to modify its separate character. These are the fauna 

 of the Indian Ocean and that of the Pacific. According to 

 Mr. Woodward's map of the Molluscan provinces, the Australian 

 and New Zealand Marine Mollusca are united together ; but with 

 the exception perhaps of one genus named on the map (Rotella), 

 all of the genera mentioned are equally common on the east 

 Australian coast. While admitting the difficulty of entering into 

 detail upon a small map, or indeed any map, it must be said that 

 the information generally given on these subjects has been hitherto 

 misleading. 



On the north coast the fauna is that of the Indian Archipelago, 

 into which the Australian element enters very slightly. By 

 North Australia I understand the north-east and north-west coast 

 within the tropics. On the coral reefs of the Great Barrier Reef 

 one sees the same, or nearly the same shells that are exposed for 

 sale in the sampans of Singapore or Penang. The relative 

 proportions seem to be the same. In North Borneo and the 

 adjacent islands one sees the same Marine Molluscan fauna. In 

 fact, it would be very difficult for even an accomplished expert to 

 say whether a collection of shells was made on the Barrier Reef, 

 on the coast of Borneo, or in the Straits of Malacca. Indeed, the 

 differences between North Australia and the Philippine Islands 

 in the fauna we are dealing with, are mostly to be seen in the 

 small or minute shells, and one or two species. The large and 

 showy cones, Trochus, Turbos, Nautilus, Olives, Thorny Woodcocks, 

 Clams, Pearl-oysters, &c.j are the same in both places and all 

 through the intermediate region. A very few species are local, 

 and probably all but the professional conchologist would regard 

 them as no more than varieties. This Indo-Malayan fauna may 

 be said to extend on the eastern coast as far south as Cape Byron, 

 the most easterly point in Australia, which is considerably outside 

 the tropics. The reason for this is the warm current which 

 extends along the coast from the equator. I am judging by the 

 fauna alone when I say that I believe this warm current is 

 deflected from the land gradually outside the tropics ; but it must 

 make a sudden turn to the eastward, for, at Lord Howe's Island, 

 which is almost due east from Sydney, a tropical marine fauna 

 flourishes, with reef -building corals such as are not found anywhere 

 south of Cape Byron, on the East Australian coast. 



But even as far as Port Jackson and to the south of it 

 considerably, some few characteristically tropical species are found. 

 Thus Typhis arcuatus, Hinds,* Nassa coronata, Lamarck, Mitra 

 pacifica, Reeve, Turbo squamosus, Gray, Buccinulus coccinatits, 

 Reeve, Tellina striatula, Lamarck, Chione marica, L., all distinctly 



*This is found as far south as Tasmania. 



