780 The Siphonophores. [ October, 
terminal filament on each knob, but there is no involucrum such 
as we have already shown covers the “sacculus,” or body of the 
knob in Agalma. Moreover, these knobs do not hang from 
tentacles, but each one is suspended separately from the base of 
the polypite, and what appear to be tentacles are in reality their 
pedicels very much elongated. 
All the genera mentioned in the previous pages constitute a 
natural group of float-bearing jelly-fishes. They are closely 
allied to one another, and all possess an air bladder or float. 
‘There remains one: more genus to be described, which is 
doubly interesting from its great size and its relationship to a 
group of tubular jelly-fishes which has little in common with 
Agalma. This genus is called Apolemia, and is known to the 
Italian fishermen, on whose shores it is most abundant, as the 
“Jana di mare,” or wool of the sea. It often reaches, when 
extended, a length of from twenty to thirty feet, and is seldom 
found entire, but generally in the form of broken fragments like 
that figured in Fig. 14} 
The main difference between Apolemia and Agalma lies in the 
fact, that while in the latter the covering-scales are fastened along 
the whole length of the polyp-stem, and no visible break occurs 
where these structures are not found, in Apolemia the feeding- 
polyps and covering-scales are united together in clusters at inter- 
vals on the stem, separated from each other by a bare portion (a) 
of the axis, which is destitute of appendages of any kind. The 
fragment figured above gives a general view of a portion of such 
an Apolemia, but if the whole colony were figured and the 
remainder of the axis shown, upon one end would be found a 
float just as in Agalma, and four or five pairs of swimming-bells, 
arranged in a like biserial manner. There is, however, this pecl- 
liarity of the portion of the stem, which bears the nectocalyces 
in Apolemia, that from it also hang bodies closely resembling 
“ tasters,” yet destitute of tentacular filaments. This 1s, as far as 
I know, the only instance among the Physophorida where the 
nectostem has tasters arising from it. They are not as a conse 
quence found along the polyp-stem as in most other genera. 
If now we turn our attention to an examination of the clusters 
of bodies arranged at intervals along the polyp-stem as in Fig. 13, 
we find each cluster of peculiar shape, differing greatly from 
‘The figure (Fig 14) was copied from the Bull. Mus. Comp. Zool., Vol. V1; No.7: 
