774 The Siphonophores. [October, 
respect does this axis differ from that of Agalma, with which it is 
morphologically identical. 
The appendages to the axis are few in number, but very im- 
portant. Whatever structures hang from its walls are those only 
which are necessary to the life of an anima! so low in structure 
as Rhizophysa. There are no swimming-bells for propulsion 
through the water. It is a passive agent of wind and tide, and 
like many other pelagic animals, irrespective of itself is help- 
lessly borne along hither and thither as they carry it. Covering: 
scales also fail along the stem, for they likewise are needless i 
an organism of this low kind. The organs necessary to the life 
of the animal, those of digestion and reproduction, cannot fail, 
and these are all which are to be found appended to the walls of 
the body of Rhizophysa. 
At intervals along the stem, when expanded as shown in Fig. 
I1,' there will be noticed flask-shaped bodies, which closely t® 
semble the polypites of the Agalma colony. These are the 
“ feeding-mouths,” and if the distal end of each of these bodies be 
examined, an opening through which the food is taken in will be 
found, while in the cavity of the polypite the half digested fragments 
of small animals betray at once the character of these bodies. 
The cavity of this polypite communicates with that of the body 
extending from one end to the other of the axis, through which !t 
is brought into connection with the interior of every other orga? 
of the animal. 
From the base of each of these feeding-polyps, there hangs 
down a long tentacle, beset along its whole length with saeco? 
or tentacular-knobs of a form very different from that of ad 
Agalma. There are three kinds of these pendants, each of vice | 
has a characteristic shape which is very different from that figuree 
in my former article, as of the tentacular-knob of Agalma eae 
There is no other structure in the organization of the Sipho - 
phore which varies so much and assumes such a variety “6 rae 
as the tentacular-knobs, and upon these differences we rely in ae 
main for generic and specific characteristics among the sai 
phores. Rhizophysa has three kinds of these tentacular el » 
dages, and in that respect differs from most other Siphonopho 
where only one form of pendant is found in the adult. - 
i ; Bos f, SOG” 
* Fig. 11 was taken from a paper by the author of this sketch in Proc. : 
Nat. History, Vol. xx. Boe 
