SeRTULARIANS. BAD I ATA. SXPHONOPHORIANa. 
more interesting tlian tlie exliibition of tliis pretty 
form magnified to about fifty diameters. 'I’lie cells 
are pei fect little wine-glasses, both in form and glass- 
like appearance. 
OCEANA languida) measures from one to 
two inches in diameter in the adult, and is so trans- 
parent and delicate that it is not readily seen. It is 
slow and languid in its movements, remaining in deep 
water, except when the sunshine is most intense. Its 
Hydroid source is a Campanularia. 
CLYTIA {Glytia hicophora) measures about half 
an inch in diameter, and is closely allied to Oceana. 
It is nocturnal in its habits, more active than the 
latter, and easily recognized by the black base of its 
tentacles. 
ZYGODACTYLA {Zygodactyla grcenlandica). — 
Bi'andt gives this genus the name of 'I’win-finger; 
hence the Greek term used here. 'I'his species is 
found on our coast, and measures about eight inches 
in diameter. 'I’he disk is of a light-violet color, deli- 
cate and transparent. 
TIMA {Tima formosa). — 'I'he robust and solid nature 
of this genus is peculiar, yet it is as transparent and 
delicate as the other forms. 'I'he adult is about two 
inches in diameter, is veiy active, moving with much 
grace and precision. 
LAOMEDIA {Laomedia amphora). — “'I'he Medusm 
of the Canipanularians are not all free. On the con- 
trary, in many of the species they always remain at- 
tached to the Ilydroid, never attaining so high a 
developmenfr as the free Medusae, and withering on 
the stem after having laid their eggs.” Such is the 
subject of this description. 'I’he species inhabits the 
piers of the bridges over the Charles River, Roston, 
and measures from twelve to eighteen inches in length. 
SER'I’ULARIANS. 
'I’his is another group of Hydroid Polyps closely 
allied to Campanularia, though differing from them in 
the arrangeitient of the sterile Ilydrae upon the stem. 
'I'hey are graceful in form: some are like miniature 
trees, and others hang like streamers from the great 
Laminarian sea-weeds. Dyphasia pumila is very 
abundant on weeds at low-water mark. 'I'ree sertu- 
EARIA (D. rosacea) is the branched species. 'I'he Me- 
dusae of both these species wither upon the stalk. 
Lal'cea cornuta is the only one known in the adult 
state. 
'I’UBULARIANS. 
'I’his is a small group of larger individuals than the 
preceding, and embraces forms whose head has a 
simple wreath of coronal tentacles, and a proboscis 
with simple tentacles around the mouth. Some of 
them grow singly, like the Hybocodon, which grows 
several inches high. 'I’ubuearia (T. couthouyi) re- 
sembles a small palm-tree, with its rings or scars of 
growth on the stalk, and its top of leaf-like organs, 
from whence hangs a bunch of undeveloped buds of 
Medusae. Bourgainviei.ia (B. superciliaris) is bell- 
shaped ; the tentacles are numerous, but fine and 
thread-like. Sarsia (Coryne mirabilis) is a small bell- 
cclxxix 
shaped Medusa, named in honor of Sars, the zoolo- 
gist, which grows in patches on the rocks between 
tides. 'I’he adult is about half an inch in diameter, 
pear-shaped, with along proboscis proti'uding through 
a wide circular opening at the truncated end ; there 
are four long slender tentacles. Memcertum (.M. 
campanula). — 'I’he disk and tentacles are yellowish, 
and the eight ovaries of a darker shade; its diame- 
ter is about one inch. Hydractinia (H. polyclina) 
was long known in little colonies on the shells in- 
habited by Hermit Grabs. 'I’hey have since been 
found attached in great masses, having the appearance 
of soft moss or cut velvet, to rocks in the tide-pools 
of our bays. They are of a rosy color. Hybocodon 
(H. politer) derives its name from its unsymnietrical 
shape, one large tentacle only being developed. Dys- 
morphosa (D. fulgurans). — In this genus the buds 
come from the proboscis ; the species is common, 
aiid produces the bluish phosphorescence noticeable 
occasionally on the sea. Nanomina (N. cara) is when 
young a single Hydra, with an oblong bubble-like 
appendage. It is very simple, being almost wholly a 
digestive cavity. Where the bubble joins the body, 
numerous buds are produced, which rapidly assume 
the shape of separate Medus®. 'I’he bubble acts as 
a float to support the structure in the water. 
SYFHONOBHOIHANS. 
PHYSALIA ; PORTUGUESE MAN-OF-WAR (P. are- 
thusa). — 'I’his belongs to the group Syphonophora, 
which consists of free-moving communities, each 
made up of individuals of different kinds, yet all ap- 
pearing to form one complicated animal. 'I’he species 
is one of the most remarkable of the group. 'I’he rich 
purple and blue which decorates every portion except 
llie crest, renders it the most brilliant and showy ob- 
ject on the ocean. Its most conspicuous i)ortioii is 
a floating bladder, with a delicate ruffle-like crest, 
pearly in lustre and color. Acalephce, Plate 2, fig. 2, 
exhibits a species of Physalia ; but the American one, 
which is common to the shores of the Gulf States 
and along the Gulf Stream to Gape Hatteras, is 
larger, moi'e symmetrical and pleasing in shape. 
During a long residence in Florida we had many op- 
portunities to examine this beautiful object. By 
means of a “ water-box,” which renders the surface 
of the water perfectly smooth, we were able to view 
the action of the tentacles of the Physalia, and lV)und 
to our surprise these dreaded organs surrounded by 
several small Fishes of a blue color, which looked so 
much like the shade of the Hydroid itself that we' 
thought them pai't and j)arcel of it; and indeed 
they are in one sejise. In lifting the animal from the 
water, which can be done with impunity l)y seizing 
it by the crest, the Fishes dart away ; but by carefully 
surrounding the tentacles with a bucket, the Fishes 
can also be secured. It seems remarkable that an 
animal possessed of the power of killing Fishes larger 
than these little companions, allows them to remain 
unharmed and like a part of the establishment, and 
that such a highly organized form as a Fish should 
be a parasite to such a simple creature. 
