1172 JOVRNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XX. 



as rapid as that of the stalked forms. Professor Herdman found specimens 

 of Balanus amphitrite (perhaps the commonest Indian species) on May 9th 

 on baskets which had been placed in the sea off Galle (Ceylon) on April 

 17th. These specimens measured from 3 to 8mm. in basal diameter, and 

 some of them were sexually mature (see Herdman's " Report on the 

 Ceylon Pearl Oyster Fisheries/' part v, p. 147). Balanus amphitrite is a 

 widely distributed species, the size of which varies greatly in different 

 circumstances ; on the East Coast of India the basal diameter of fully 

 grown specimens is usually about 14mm. B. tintinnabulum, also a common 

 species in all warm seas, usually reaches a larger size than B. amphitrite. 

 The base of the largest of the three specimens sent me by Mr. Millard 

 measures 56 X 59mm. These specimens were taken from the bottom of a 

 light-ship in Bombay Harbour and must have been less than nine months 

 old. I have examined another specimen of this species, the base of which 

 measured 60 X 65mm. It was known to be not more than a year old, and 

 was from the Gulf of Manaar (" Mem. As. Soc. Bengal," i, p. 79, footnote). 

 Darwin puts on record a statement that specimens of B. tintinnabulum, 

 measuring from 5 to 6 inches in diameter, have been found on ships that 

 had been to sea for not more than a year, while he himself found, on the 

 Coast of Chile, a specimen of a somewhat similar species (B. psittacus) that 

 had attained a basal diameter of 1-3 of an inch on a chain that had been 

 six months under water. 



These observations, scattered and incomplete as they are, give some idea 

 of the rapid growth of barnacles on ships' bottoms and in similar situations, 

 but valuable observations of a more precise nature might be made without 

 much difficulty in a sea-port provided like Bombay with an extensive 



harbour. 



N. ANNANDALE, 

 Indian Museum, Calcutta. 

 December 16th, 1910. 



