EUPAGURUS. 553 



a suitable time and method for catching them is 

 chosen, they can be obtained in large numbers. Like the 

 fresh- water My sis, they spend the day at the bottom of 

 the sea and rise to the surface at night. The Glaucothoe 

 has a carapace, of adult shape, but the branchiostegite is 

 not bent down at right angles to the cephalic shield. 

 Pleopods are present on all but the first abdominal 

 somite, and the right uropod is smaller than the left. 

 The otocysts have now appeared. It is during this stage 

 that the animal first seeks a moveable residence and the 

 larvae spend their time in alternately prowling on the 

 bottom and swimming about. The stage usually lasts 

 four or five days, and in that period the livers, excretory 

 bladder and gonadial organs shift to the abdomen, while 

 the more superficial structures undergo degeneration. 

 The abdominal muscles become modified, the right 

 pleopods disappear, and those on the left side degenerate. 

 The metamorphosis is not dependent on a body covering, 

 but completes itself even if the animal is kept naked, 

 although the stage lasts much longer (up to six or eight 

 days) and the mortality is very high. 



"The anatomical modifications that appear during 

 the Glaucothoe stage are, with but one exception, 

 uninfluenced by either the presence, absence or form of 

 the shell. The exception is found in the retention of 

 rudimentary pleopods on the right side of the body in 

 the sixth stage, though typically at this period appen- 

 dages should be absent from this side." — (Thompson.) 



Adolescent phase. — In this stage the typical 

 adult structure is attained. The organs develop com- 

 pletely and the pleopods definitely show the sex of the 

 animal, but Thompson finds that sexual maturity is not 

 reached till a year or more after the moult from the 

 Glaucothoe stage to the young adult. 



