274 THE VOYAGE OF H.M.S. CHALLENGER. 



or sandy mud, but those from deep water are found on various kinds of deposit, including 

 " grey ooze," " globigerina ooze," " red clay," and " hard ground." 



Temperature also appears to have little influence upon the distribution of the 

 Ascidise Simplices, as the temperatures of their localities range from nearly freezing point 

 upwards. 



