796 THE VOYAGE OF H.M.S. CHALLENGER. 
systems has been dredged by the U.S.S. ‘ Blake.’ Flctbellum apertum (fig. 285) is 
interesting because it was dredged at two very distant localities, viz., off* Portugal in 
900 fathoms, and off Prince Edward Island in 310 fathoms. 
Pis. 286 . — Lophohelia prolifera, M.-Echv. and Haime ; three-fourtlis the natural size. 
Fig. 285 Flctbellum apertum, Moseley ; natural size. Off Prince Edward Island, 310 fathoms. 
“ The most abundant of the very few compound Madreporarian corals which inhabit 
deep waters is Lophohelia prolifera (fig. 286). It varies very much in form and mode of 
growth, and sometimes forms bushes of considerable size. It occurs in the Mediterranean 
with Precious Coral ( Cor allium rubrum), off the English and Norwegian coasts in 100 
fathoms or so, and all over the Atlantic, off Tristan da Cunha in the south, off 
