REPORT ON THE CRINOIDEA. 139 
much wider geographical range than Metacrinus, also extends to a greater depth ; while 
the same contrast, including also thermal range, may be noticed between Antedon and 
the stalked Crinoids generally. It is somewhat singular that this widely distributed 
genus, which was dredged at 2900 fathoms in the Pacific and at 2600 fathoms in the 
Southern Sea, should not have been met with between the latter depth and 1600 
fathoms. 
C. Tur AssocraTION OF THE GENERA AT PARTICULAR STATIONS. 
The mode of grouping of the various genera of Crinoids, both stalked and free, which 
have been obtained at different Stations and by the exploring expeditions of various 
countries, presents some points of interest. The Challenger dredged Comatulz at forty-five 
Stations, and stalked Crinoids at sixteen. If the different North Atlantic expeditions of 
the British and Norwegian Governments be also reckoned, this last number rises to 28. 
A single species of stalked Crinoid was found at several Stations, unaccompanied by 
any Comatulze, as shown in the following Table. 
Taste 1V.—Showing the number of times that Isolated Species of Stalked Crinoids 
have been Dredged. 
Rhizocrinus, | Bathyecrinus. Hyocrinus. Pentacrinus. | Metacrinus. 
Challenger— 3 1 u 1 
2 (young? jide C.W.T.) 
North Atlantic Expe- 
ditions— 
1. British. 7 1 ae 1 
2. Norwegian. 8 4 
At eleven Stations during the Challenger and “Porcupine” Expeditions which yielded 
stalked Crinoids, there were either more than one species, or if only one was obtained it 
was associated with one or more species of Comatulz (see Table V.). Pentacrinus has 
been found associated with all the Comatulid genera except Thaumatocrinus, which was 
only obtained once in the Southern Sea, considerably beyond the most southern limit 
of Pentacrinus. 
The ‘ Blake,” however, dredged Pentacrinus in shallower water than was worked by the 
Challenger; and found it associated with Actinometra at nine out of the fifty-four Stations 
at which stalked Crinoids were obtained (see Table VI.). As in the case of the Challenger 
and ‘“ Porcupine,” the two species of Rhizocrinus were never found at the same Station, 
