NOTE ON SOME POST-PLIOCENE MOLLUSCS FKOM THE BYCULLA FLATS. 189 



a muddy bottom, surrounded by coral reefs, on the island of Battoo, 

 near Sumatra, which was exposed by a violent earthquake. The 

 largest was 5 feet 4 inches in length and 9 inches in circumference at the 

 base, tapering upwards to 2£ inches. Most of them were covered with 

 small Oysters and Serpulae for about a foot from their upper extremity, 

 showing that they must have protruded that distance from the 

 muddy bottom upwards into the water. But owing either to the 

 depth or the muddiness of the water, they had escaped notice till the 

 natural convulsion which laid bare the bottom of the bay. 

 Mr. Griffiths remarked that the large end was completely closed, and 

 had a rounded appearance and was very thin, while the small end was 

 very brittle and divided by a longitudinal septum running down 

 for 8 or 9 inches. Many of the shells he described as nearly straight, 

 while others were crooked and contorted. The substance of the shell 

 he described as having a fibrous and radiated appearance. And 

 herein lies the only essential difference between his specimens and 

 these before you, which for the most part present a concentric, not 

 radiated, appearance.* In all other particulars they approach very 

 nearly to Mr. Griffiths' Battoo Shells, except in their smaller size. 



Godfrey Sellius had been the first in 1733 to recognise a true 

 bivalve mollusc in Teredo. But it was reserved for Sir Everard 

 Home, R. N., in 1806 to discover a species of Teredo in the shells 

 Mr. Griffiths had found at Battoo. He bestowed on it the name of 

 Teredo gigantea. He published his discovery in a paper entitled 

 " Observations on the Shell of the Sea-worm found on the Coast of 

 Sumatra, proving it to belong b to a species of Teredo," and presented 

 the specimens from Battoo, as well as others found in " Another inlet 

 of the sea, sticking out from rather hard mud mixed with sand and 

 small stones from 8 to 10 inches or more and from 1 to 3 fathoms 

 underwater," to the Museum of the Royal College of Surgeons. 

 Unfortunately these have now all disappeared, except two marked 

 E348 and E 349c. They are thus described in the Catalogue :— 

 "E348. — Teredo (Furcella) arenaria — Rumph. sp. (Teredo gigantea. 

 Home). Habitat : Indian Ocean. Presented by Capt. Sir E. Home, 

 R. N. E349. — Specimens marked a to i. c. — The terminal portion 

 of the shell and the double tube." 



* In some instances the outer and inrer layers are shelly and those in the centre dis- 

 tinctly crystalline. In a few the texture of the shell is crystalline throughout. The animal 

 could not h*ve formed a crystalline shell. But by the action ef the mud or water in 

 which it was depisited the shell may have been cystallized, as I have pointed out is com- 

 mon with those found near the brick-fields on the west of the Flats ; and the crystals may 

 have been subsequently decomposed by some other inflnence on the surfaces exposed to it. 



