PRESIDENT'S ADDRESS. 5 



observation of the larvae of Echinodermata and other 

 allied marine groups has been successfully carried on at the 

 Plymouth Marine Station, and this has now been extended 

 to the Copepoda, which enables their development to be more 

 carefully studied than by isolated observations on them in 

 their natural state. In the cruise of the Albatross in 1906, 

 great quantities of Crinoids were met with, and a monograph 

 has recently been published on this group, shewing it to be 

 much richer and more important, as regards living species, 

 than had hitherto been thought to be the case, though the 

 fossil series is, of course, very extensive. In the Philippine 

 Islands it has been observed that the Crustaceans Atya and 

 Caridina have their chelse furnished with long hairs. Atya, 

 when feeding in a running stream, rests with these hairs 

 projecting up the stream so that they may catch any 

 organisms that are carried along in the water. Caridina 

 uses them as brushes to brush up any food on the bottom. 

 In regard to the number of growth rings on the shell of an 

 oyster as a sign of its age it has been lately shown that an 

 oyster of 18 months may have from two to five rings, one of 

 2J years the same, or six rings, one of 3| years (4 summers) 

 from three to eight. The test is not therefore very reliable. 

 It is to be regretted that two oyster-parasites, introduced 

 originally from America with oysters, a Venus shell, Petricola 

 pholadiformis, and a slipper-limpet, Crepidula fornicata, are 

 spreading considerably, the former having now reached 

 the Dutch Coast. A good deal of information on the subject 

 of determining the age of fish by means of the growth rings 

 on their scales has been obtained from experiments near 

 Iceland and the Faroe Isles, in which marked cod were 

 liberated and more than half of them captured again a year 

 or more later. Fish have been scarce owing to the war, but 

 a record catch for a single boat has been made of 280,000 

 herrings. In the Lake of Tiberias it has been found that 

 there are a certain number of genera and species which 

 are identical with Ethiopian forms, showing a former 

 connection. These forms are all fish, and none of them the 



