HYKROZOA. 



59 



II fringe of fiuc tentacles on those invervening portions, the '-•■'- *" 

 the bifid arms now occupying the notches in the rim ami f 

 the lappets of the sense-organs ; the medusa is now recognisahle ob 

 Aurelia. 



The fixed Scyphistoma stage is not common, many Sovpho- 

 medusiii developing direct from the egir. The Scyphometliwa.' art- 

 divided into four Orders. The first Order ineludes the exceptional 

 Lwernarm-Haliclystus {Lucernaria) octorudi<itus * (Fig. 22) is shaf>ed 

 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 



Fi<i. "22. 



Haliclyitus octnnidlatu^, a Luceriiariaii ^rcdusn. ou sea weed, a, mouth 

 and stomach ; h, tentacles; c. ancliors; d, ivprodiictive glands. ( I-'mm 

 JoliDston's British Zoophytes ; tigurea 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, Polagia, Aurelia, Pilema, ('»ty- 

 lorkiza, &c. (see Case 3). In Pilema (Fig. 23) and other " Khizu- 

 stomatous" forms the lips and arms of the manubrium are fuseil 

 together, and the food, consisting of minute marine organisms, is 

 taken in through little suctorial mouths and conveyed up lomr 

 canals. Pilema odojms* is fairly common. Si)eciniens often attain 

 a diameter of two feet. The greenish umbrella has a purple frill- 

 like margin : there are eight tentaculo-cysts with their sjxoial 

 lappets, i)ut there are no tentacles round the margin of th.- 

 umbrella. Tlie large mouthless manubrium breaks up into eight 

 long arms often attaining a length of two feet; the minute. 



I'pright pari. 



