CHARACTERISTIC DEEP-SEA TYPES. — WORMS. 57 
It is interesting to find that the Serpulidee (Fig. 272) also 
occur at great depths, because Ehlers, in working up the an- 
nelids of the “Porcupine” expedition, had no- 
ticed their absence in deep water, and left it 
undecided whether they were excluded by the 
peculiar nature of the bottom or by the Low tem- 
perature of the deep sea. But it 
is not uncommon in the deep water 
of the Gulf of Mexico to bring up 
rocky fragments which, judging from 
the amount of mud brought up by 
the trawl at the same time, must 
Vic. Si — Persio form isolated patches, and in these 
stegus stellatus. 2. undoubtedly the Serpule thrive. 
(Fig. 273.) Terebellide and Serpu- 
lide have been obtained by the “Challenger ” at 
depths of nearly 3,000 fathoms. Of course, where 
the tubes are composed of secretions, as in Hyali- 
neecia, they are independent of their surroundings 
and of the character of the bottom. But the Fig. 273. 
majority of the tube builders depend upon the Hyalopomatus 
material at their disposal, using, to strengthen their € €. 
tubes, either sand, or mud, or larger solid particles, such as 
foraminifers, bivalves, sponge spicules, and the like. 
