REPOET ON THE HYDROIDA. 
21 
Campanularia ptychocyathus is a minute creeping form and is rendered specially 
remarkable by the difference of texture in the walls of the hydrothecse. These for about 
the distal third of their height become so thin and collapsible that during the retracted 
state of the hyclranth they are generally seen to have fallen towards one another and 
become thrown into irregular plicae which obscure the true form of the hydrotheca, 
withdrawing from view- its regularly dentate margin, a condition, however, which must 
not be confounded with that of the opercular segments which crown the hydrothecse in 
Campanulina and some allied forms. The proximal two-thirds of the hydrothecse 
possess on the contrary the usual firmness of these parts, and the hydrotheca here 
retains at all times its true form. The peduncle presents two or three annulations just 
below the hydrotheca, and several at its origin from the stolon, while a group of rings 
near the mi ddle of its length is also generally present. 
The gonangia are developed from the creeping stolon between the peduncles of the 
hydrothecse. They are rendered striking by their nearly cylindrical form, and the 
constriction which exists immediately below the broad truncated summit. On one 
or two occasions gonangia were found springing from the peduncle of the hydrotheca. 
The gonangia in the specimen are those of a female colony. 
Campanularia retrojlexa, n. sp. (PI. XI. figs. 1, la). 
Trophosome. — Hydrocaulus a creeping, filiform, reticulated stolon from which the 
peduncles of the hydrothecse are sent off at short intervals. Hydrothecse deep, 
cylindrical, with the margin divided into about fourteen blunt teeth and abruptly 
everted. Peduncles either quite continuous or divided by transverse joints into long 
clavate internodes. 
Gonosome not known. 
Locality. — Honolulu ; depth, 20 to 40 fathoms. 
The abruptly everted margin of the deep cylindrical hydrothecse gives to this little 
Campanularian , which attains a height of about tw r o-tenths of an inch, a well-marked 
character. The margin is everted in a plane at right angles to the axis of the hydrotheea, 
and the teeth into which the rim is divided stand up from it parallel to the axis, 
thus suggesting the form of the escapement-wheel of a watch. 
The peduncles of the hydrothecse are in most instances intersected by rather distant 
constrictions, and thus divided into a series of segments. Each of these has a somewhat 
clavate form, being slightly thicker at its distal than at its proximal end. This con- 
dition, how T ever, notwithstanding its rather striking character, is not universally present, 
some of the peduncles being of uniform thickness and destitute throughout of con- 
strictions. 
The specimen occurs growing over the surface of a Millepore. 
