THE ROCK-BARNACLE 71 



It was necessary to put the results of the two naturalists 

 together in order to attain the complete life-history, and 

 this can now be readily done. Thompson had described 

 the last larval stage of the rock-barnacle and the first 

 larval stage of the stalked barnacle. Burmeister had de- 

 scribed both stages of the stalked barnacle. Has the 

 rock-barnacle as well as the stalked barnacle a first larval 

 stage, differing from that which undergoes the transfor- 

 mation ? Thompson never put or answered this question, 

 but it was not long before Harry Goodsir (at Edinburgh 

 in 1843) discovered that the rock-barnacle has an earlier 

 stage quite distinct from the late larva with bivalve shell. 



I have not yet finished the story of barnacle-develop- 

 ment, but we will break off here, and wait for an oppor- 

 tunity of examining fresh larvae of the barnacles. 



This bright April afternoon is capital for tow-netting. 

 There is so little wind that we have often to put out the 

 oars in order to keep the net extended. Sometimes we 

 are content to lie motionless for half an hour together, 

 and then all is still except for the chuckling of little waves, 

 which leap up against the sides of the boat. The water 

 is absolutely clear, such water as we only get on our 

 western shores ; and looking over the side I can see 

 groves of sea-weed and corallines, with here and there a 

 sea-urchin, a star-fish, or a sea-slug. A large fish sculls 

 himself gently in and out of the weedy recesses, and crabs 

 clamber over the rocks. Now and then I pull in the 

 tow-net, turn its long cone of muslin inside out, and wash 

 it in a beaker of sea-water. 1 There are many small crea- 



1 The tow-net has a long cone of muslin attached to its hoop, and this 

 is held by a cord. After being towed for some time by a slow-moving 

 boat, the net is hauled in, and its contents examined. 



It is a good plan now and then to send to the Marine Laboratory at 

 Plymouth for a supply of what is called " Plankton," an assemblage of 

 minute life from the surface of the sea. A bottle will be received, con- 

 taining nauplii, crab-larvae, medusae of Obelia, the worm Sagitta, and many 

 more pelagic animals. Early summer is a good season for these things. 



