CRUSTACEA OF THE DEEP SEA 129 



Some species have been found to have the food- 

 canal filled with Globigerina ooze, which they no 

 doubt swallow, as earth-worms do the soil in which 

 they burrow, for the purpose of extracting the nutri- 

 ment that it contains. In one species of deep-sea 



FIG. 44Thaumastocheles zaUucus. REDUCED. (After Spence Bate.) 



Cumacea (Platycuma holti), which appears to feed in 

 this manner, the food-canal is coiled, a condition 

 very rare in Crustacea ; in all probability this is due 

 to the necessity for an increase of the absorptive 

 surface, since it is common to find such an increase, 

 either by lengthening and consequent coiling of the 

 9 



