728 Proceedings of the Boy at Society 
The Belation of the Ophiuroid Faiina to the Nature of the Bottom. 
While investigating the “Triton” collection, it occurred to me 
that results of some interest might he obtained by attempting to 
trace the manner in wl^ich the Ophiuroids are distributed with 
respect to the nature of the bottom. It was obvious at the outset 
that such an inquiry would be beset with great difficulties, owing to 
the impossibility of entirely eliminating the influeuce of the depth 
and other conditions. 
As a preliminary step, the distribution lists of Mr Lyman’s 
“Beport on the Challenger Ophiuroidea were analysed, the indi- 
cations as to the nature of the bottom being taken from a revised 
list of stations which hae been prepared for publication in the 
“I^arratiye of the Cruise of JI.M.S, ^Challenger.’” The results 
are expressed in the acppmpanyiug table, in which are given the 
number of dredgings which were made upon each deposit, the number 
of cases in which Ophiuroids were obtained, and the relation of the 
latter number to the former expressed as a percentage— 
Red 
clay. 
Glob. 
ooze, 
Red 
niud. 
Pterop. 
ooze. 
Vol- 
canic 
mud. 
Coral 
mad, 
Blue * 
and 
green 
mud. 
Total. 
Ophiuroids 
found, . . . 
5 
1,4 
3 
4 
14 
11 
46 
120 
Bumher of 
dredgings, 
38 
65 
11 
10 
30 
19 
79 
276 
Percentage, . 
13 
25 
27 
40 
47 
58 
58 
43 
The most striking fact presented by this table is that Ophiuroids 
are not commonly met with on those deposits which are charac- 
teristic of great depth, such as the red clay and Globigerina ooze ; 
while they are frequent npon the shallower bottoms made up of 
coral mud and the blue and green muds which are composed of 
continental detritus ; in other words, it shows (especially when 
taken in connection with the elaborate bathymetrical tables given 
in Mr Lyman’s Beport) that, as a rule, the abundance of Ophiuroids is 
* Zool, Chall, Exp,, part xiv. , 1882, 
