SEA SQUIRTS. 245 



Some of the primeval 

 squirt-larvae are supposed 

 to have cultivated these 

 possibilities, and the 

 LARVA OF A TUNICATE. grand vertebrate division 



of the animal kingdom 



is said to be the result ; but others went in for the status quo 



and inglorious ease. No developments for us, said they. 



They may even be supposed to have anticipated the prayer 



formerly taught to rural school children : 



" God bless the squire and his relations, 

 And keep us in our proper stations." 



Then they gave up wandering at random through the waters, 

 and settled down to a quiet and retired life on a piece of rock 

 at the root of a branching weed. Taking hold with theii 

 suckers, they soon discovered that tails and sense organs 

 were of no use to those who had forsworn wandering, 

 so they threw them off, and gradually assumed the wine-skin 

 shape that has ever since been the ruling fashion among 

 Ascidians. All that remains of the tail is a few fatty cells in 

 the posterior part of the trunk. The suckers by which it was 

 attached disappear, and the test grows over surrounding 

 objects; the auditory organ disappears, the eye retrogrades 

 into a mere pigment spot, and the nervous system degenerates 

 into the solitary ganglion to which we have already referred. 

 It will thus be seen that the life history of the Tunicates is a 

 dismal story of degeneration instead of development ; but it is 

 none the less interesting on that account. 



