F.CHINOIDEA 



333 



good ; this view can at most be true to a limited extent for 

 the species Uving in soft mud. Very probably it does not 

 lie for a long time in its hole, but must leave it now and 

 then (during night probably) and dig itself a new hole ; otherwise 

 it is hardly conceivable that it could get sufficient food, as the 

 surface round the hole in the area within reach to the tube-feet 

 could hardly avoid being soon exhausted of food particles.^ 

 The species fives rather gregariously and is one of the character- 

 istic forms of some marine animal communities. 



Fig. 195. — 1. Valve of tridentate pedicellaria ; 2. Globiferous pedicellaria 

 of Echinocardium cordatum. 3. Globiferous pedicellaria ; 4. Triden- 

 tate pedicellaria of Echinocard. flavescens. 5. Valve of tridentate 



pedicellaria of Echinocard. pennatifidum. 

 Th. Mortensen, " Ingolf "" Ech., ii.) 



1-4, x27 



o. 



36. (After 



The breeding season is in the summer-time. The larva 

 (Fig. 3, 4) has strongly thorny postero-lateral rods ; the posterior 

 process exceedingly variable in length, sometimes a mere short 

 stump, sometimes as long as the postoral arms. Point of arms 

 and of posterior process conspicuously red. The larvae are 

 sometimes found in enormous numbers and likewise the 

 young, newly metamorphosed young may be found in enormous 

 numbers in some places, and thus may be of importance as fish 

 food, as young Spatangoids in general are eaten by various 

 kinds of fishes. — The different species of Echinocardium may be 



1 This is 

 observations. 



merely a suggestion, as yet not supported by direct 



