HYDKOZOA. 
59 
a fringe of fine tentacles on those invervening portions, the ends of 
the bifid arms now occupying the notches in the rim and forming 
the lappets of the sense-organs ; the medusa is now recognisable as 
Aurelia. 
The fixed Scyphistoma stage is not common, many Scypho- 
medusse developing direct from the egg. The Scyphomedusse are 
divided into four Orders. The first Order includes the exceptional 
Lucernarice-Haliclystus ( Lucernaria ) octoradiatus * (Fig. 22) is shaped 
like a vase with a short stem. The upper edge is produced into 
eight arms each crowned with a tuft of tentacles. The animal, 
which fixes itself by its stalk, can creep along or swim. On the 
margin, between the tufts of tentacles, are peculiar modified tentacles 
known as anchoring bodies, which assist progression by sticking to 
and grasping the surface of the sea-weeds or stones. The mouth 
Fig. 22. 
Haliclystus octoradiatus , a Lucernarian Medusa, on sea weed, a , mouth 
and stomach ; b, tentacles ; c, anchors ; d, reproductive glands. (From 
Johnston’s British Zoophytes; figures slightly altered.) 
and stomach (manubrium) are in the centre. Haliclystus , which is 
commonly found adhering to sea-weeds, varies in colour, being olive- 
brown, green, or pink. The second Order (Discomedusae) includes 
the commoner kinds of Jelly-Fish, Pelagia , Aurelia , Pilema, Goty- 
lorhiza , &c. (see Case 3). In Pilema (Fig. 23) and other “ Rhizo- 
stomatous ” forms the lips and arms of the manubrium are fused 
together, and the food, consisting of minute marine organisms, is 
taken in through little suctorial mouths and conveyed up long 
canals. Pilema octopus * is fairly common. Specimens often attain 
a diameter of two feet. The greenish umbrella has a purple frill- 
like margin ; there are eight tentaculo-cysts with their special 
lappets, but there are no tentacles round the margin of the 
umbrella. The large mouthless manubrium breaks up into eight 
long arms often attaining a length of two feet ; the minute, 
Case 3, 
Upright part. 
Case 3, 
Upright part. 
